Spring全栈式轻量级开源框架③

本文介绍Spring框架中JdbcTemplate的基本使用方法及Spring事务管理的相关配置,包括编程式事务和声明式事务的实现方式,并详细讲解了基于XML和注解的声明式事务控制。

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Spring全栈式轻量级开源框架之Spring JDBCTemplate & 声明式事务

一 Spring的JdbcTemplate

1.1 JdbcTemplate是什么

  • JdbcTemplate是spring框架中提供的一个模板对象,是对原始繁琐的Jdbc API对象的简单封装。

核心对象

JdbcTemplate jdbcTemplate = new JdbcTemplate(DataSource dataSource);

核心方法

int update(); // 执行增、删、改语句

List<T> query(); // 查询多个

T queryForObject(); // 查询一个

new BeanPropertyRowMapper<>(); // 实现ORM映射封装

举个栗子

  • 查询数据库所有账户信息到Account实体中
public class JdbcTemplateTest {
    @Test
    public void testFindAll() throws Exception {
        // 创建核心对象
        JdbcTemplate jdbcTemplate = new JdbcTemplate(JdbcUtils.getDataSource());
        // 编写sql
        String sql = "select * from account";
        // 执行sql
        List<Account> list = jdbcTemplate.query(sql, new BeanPropertyRowMapper<>(Account.class));
    }
}

1.2 Spring整合JdbcTemplate

需求

  • 基于Spring的xml配置实现账户的CRUD案例

步骤分析

1. 创建java项目,导入坐标
2. 编写Account实体类
3. 编写AccountDao接口和实现类
4. 编写AccountService接口和实现类
5. 编写spring核心配置文件
6. 编写测试代码

在这里插入图片描述

1)创建java项目,导入坐标

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.myProject</groupId>
    <artifactId>spring_jdbctemplate</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>

    <dependencies>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.47</version>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.1.15</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>5.1.5.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjweaver</artifactId>
            <version>1.8.13</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>5.1.5.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-tx</artifactId>
            <version>5.1.5.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-test</artifactId>
            <version>5.1.5.RELEASE</version>
        </dependency>
    </dependencies>

</project>

2)编写Account实体类

package com.myProject.domain;

public class Account {
    private Integer id;
    private String name;
    private Double money;

    @Override
    public String toString() {
        return "Account{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", money=" + money +
                '}';
    }

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Double getMoney() {
        return money;
    }

    public void setMoney(Double money) {
        this.money = money;
    }
}

3)编写AccountDao接口和实现类

package com.myProject.dao;

import com.myProject.domain.Account;

import java.util.List;

public interface AccountDao {
    /**
     * 查询所有账户
     */
    public List<Account> findAll();

    /**
     * 根据ID查询账户
     */
    public Account findById(Integer id);

    /**
     * 添加账户
     */
    public void save(Account account);

    /**
     * 更新账户信息
     */
    public void update(Account account);

    /**
     * 根据ID删除用户账户
     */
    public void delete(Integer id);
}

package com.myProject.dao.impl;

import com.myProject.dao.AccountDao;
import com.myProject.domain.Account;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.stereotype.Repository;

import java.util.List;

@Repository
public class AccountDaoImpl implements AccountDao {
    @Autowired
    private JdbcTemplate jdbcTemplate;

    // 查询所有用户
    @Override
    public List<Account> findAll() {
        String sql = "select * from account";

        // 需要用到jdbcTemplate
        List<Account> list = jdbcTemplate.query(sql, new BeanPropertyRowMapper<>(Account.class));
        return list;
    }

    // 根据ID查询用户
    @Override
    public Account findById(Integer id) {
        String sql = "select * from account where id = ?";
        Account account = jdbcTemplate.queryForObject(sql, new BeanPropertyRowMapper<>(Account.class), id);
        return account;
    }

    // 添加用户
    @Override
    public void save(Account account) {
        String sql = "insert into account values(null, ? ,?)";
        jdbcTemplate.update(sql, account.getName(), account.getMoney());
    }

    // 更新用户
    @Override
    public void update(Account account) {
        String sql = "update account set money = ? where name = ?";
        jdbcTemplate.update(sql, account.getMoney(), account.getName());
    }

    // 根据ID删除账户
    @Override
    public void delete(Integer id) {
        String sql = "delete from account where id = ?";
        jdbcTemplate.update(sql, id);
    }
}

4)编写AccountService接口和实现类

package com.myProject.service;

import com.myProject.domain.Account;

import java.util.List;

public interface AccountService {
    /**
     * 查询所有账户
     */
    public List<Account> findAll();

    /**
     * 根据ID查询账户
     */
    public Account findById(Integer id);

    /**
     * 添加账户
     */
    public void save(Account account);

    /**
     * 更新账户信息
     */
    public void update(Account account);

    /**
     * 根据ID删除用户账户
     */
    public void delete(Integer id);
}

package com.myProject.service.impl;

import com.myProject.dao.AccountDao;
import com.myProject.domain.Account;
import com.myProject.service.AccountService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

@Service
public class AccountServiceImpl implements AccountService {
    @Autowired
    private AccountDao accountDao;

    @Override
    public List<Account> findAll() {
        List<Account> all = accountDao.findAll();
        return all;
    }

    @Override
    public Account findById(Integer id) {
        Account account = accountDao.findById(id);
        return account;
    }

    @Override
    public void save(Account account) {
        accountDao.save(account);
    }

    @Override
    public void update(Account account) {
        accountDao.update(account);
    }

    @Override
    public void delete(Integer id) {
        accountDao.delete(id);
    }
}

5)编写spring核心配置文件

  • applicationContext.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
                          http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd
">
    <!--IOC注解扫描-->
    <context:component-scan base-package="com.myProject" />

    <!--引入properties文件-->
    <context:property-placeholder location="classpath:jdbc.properties" />
    <!--配置DataSource-->
    <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">
        <property name="driverClassName" value="${jdbc.driverClassName}"/>
        <property name="url" value="${jdbc.url}"/>
        <property name="username" value="${jdbc.username}"/>
        <property name="password" value="${jdbc.password}"/>
    </bean>

    <!--配置jdbcTemplate-->
    <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
        <constructor-arg name="dataSource" ref="dataSource" />
    </bean>
</beans>
  • jdbc.properties
jdbc.driverClassName=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql:///spring_db
jdbc.username=root
jdbc.password=root

6)编写测试代码

package com.myProject.test;

import com.myProject.domain.Account;
import com.myProject.service.AccountService;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

import java.util.List;

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration({"classpath:applicationContext.xml"})
public class AccountServiceImplTest {
    @Autowired
    private AccountService accountService;

    // 测试保存
    @Test
    public void testSave() {
        Account account = new Account();
        account.setName("lucy");
        account.setMoney(1000d);
        accountService.save(account);
    }

    // 测试查询
    @Test
    public void testFindAll() {
        List<Account> all = accountService.findAll();

        all.forEach(System.out::println);
    }

    // 测试根据ID查询
    @Test
    public void testFindById() {
        Account account = accountService.findById(2);
        System.out.println(account);
    }

    // 测试更新
    @Test
    public void testUpdate() {
        Account account = new Account();
        account.setName("lucy");
        account.setMoney(1000d);
        accountService.update(account);
    }

    // 测试删除
    @Test
    public void testDelete() {
        accountService.delete(4);
    }
}

1.3 实现转账案例

步骤分析

1. 创建java项目,导入坐标
2. 编写Account实体类
3. 编写AccountDao接口和实现类
4. 编写AccountService接口和实现类
5. 编写spring核心配置文件
6. 编写测试代码

1)创建java项目,导入坐标

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.myProject</groupId>
    <artifactId>spring_transfer_tx</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>

    <dependencies>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.47</version>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.1.15</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>5.1.5.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjweaver</artifactId>
            <version>1.8.13</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>5.1.5.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-tx</artifactId>
            <version>5.1.5.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-test</artifactId>
            <version>5.1.5.RELEASE</version>
        </dependency>
    </dependencies>
</project>

2)编写Account实体类

package com.myProject.domain;

public class Account {
    private Integer id;
    private String name;
    private Double money;

    @Override
    public String toString() {
        return "Account{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", money=" + money +
                '}';
    }

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Double getMoney() {
        return money;
    }

    public void setMoney(Double money) {
        this.money = money;
    }
}

3)编写AccountDao接口和实现类

package com.myProject.dao;

public interface AccountDao {
    /**
     * 转出操作
     */
    public void out(String outUser, Double money);

    /**
     * 转入操作
     */
    public void in(String inUser, Double money);
}

package com.myProject.dao.impl;

import com.myProject.dao.AccountDao;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.stereotype.Repository;
@Repository
public class AccountDaoImpl implements AccountDao {
    @Autowired
    private JdbcTemplate jdbcTemplate;

    @Override
    public void out(String outUser, Double money) {
        String sql = "update account set money = money - ? where name = ?";
        jdbcTemplate.update(sql, money, outUser);
    }

    @Override
    public void in(String inUser, Double money) {
        String sql = "update account set money = money + ? where name = ?";
        jdbcTemplate.update(sql, money, inUser);
    }
}

4)编写AccountService接口和实现类

package com.myProject.service;

public interface AccountService {
    /**
     * 转账方法
     */
    public void transfer(String outUser, String inUser, Double money);
}

package com.myProject.service.impl;

import com.myProject.dao.AccountDao;
import com.myProject.service.AccountService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

@Service
public class AccountServiceImpl implements AccountService {
    @Autowired
    private AccountDao accountDao;

    @Override
    public void transfer(String outUser, String inUser, Double money) {
        // 调用dao的out方法和in方法
        accountDao.out(outUser, money);

        accountDao.in(inUser, money);
    }
}

5)编写spring核心配置文件

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
                          http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd
">

    <!--IOC注解扫描-->
    <context:component-scan base-package="com.myProject"></context:component-scan>

    <!--引入properties文件-->
    <context:property-placeholder location="classpath:jdbc.properties"></context:property-placeholder>

    <!--配置dataSource-->
    <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">
        <property name="driverClassName" value="${jdbc.driverClassName}" />
        <property name="url" value="${jdbc.url}" />
        <property name="username" value="${jdbc.username}" />
        <property name="password" value="${jdbc.password}" />
    </bean>

    <!--jdbcTemplate-->
    <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
        <constructor-arg name="dataSource" ref="dataSource" />
    </bean>
</beans>

6)编写测试代码

package com.myProject.test;

import com.myProject.service.AccountService;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration({"classpath:applicationContext.xml"})
public class AccountServiceImplTest {

    @Autowired
    private AccountService accountService;

    @Test
    public void testTransfer() {
        accountService.transfer("tom","jerry", 100d);
    }
}

二 Spring的事务

2.1 Spring中的事务控制方式

  • Spring的事务控制可以分为编程式事务控制和声明式事务控制。

编程式

  • 开发者直接把事务的代码和业务代码耦合到一起,在实际开发中不用。

声明式

  • 开发者采用配置的方式来实现的事务控制,业务代码与事务代码实现解耦合,使用的AOP思想。

2.2 编程式事务控制相关对象【了解】

2.2.1 PlatformTransactionManager

  • PlatformTransactionManager接口,是spring的事务管理器,里面提供了我们常用的操作事务的方法。
方法说明
TransactionStatus getTransaction(TransactionDefinition definition);获取事务的状态信息
void commit(TransactionStatus status);提交事务
void rollback(TransactionStatus status);回滚事务

注意:

* PlatformTransactionManager 是接口类型,不同的 Dao 层技术则有不同的实现类。

* Dao层技术是jdbcTemplate或mybatis时:
	DataSourceTransactionManager
	
* Dao层技术是hibernate时:
	HibernateTransactionManager
	
* Dao层技术是JPA时:
	JpaTransactionManager

2.2.2 TransactionDefinition

  • TransactionDefinition接口提供事务的定义信息(事务隔离级别、事务传播行为等等)
方法说明
int getIsolationLevel()获得事务的隔离级别
int getPropogationBehavior()获得事务的传播行为
int getTimeout()获得超时时间
boolean isReadOnly()是否只读
1)事务隔离级别
  • 设置隔离级别,可以解决事务并发产生的问题,如脏读、不可重复读和虚读(幻读)。
* ISOLATION_DEFAULT 使用数据库默认级别

* ISOLATION_READ_UNCOMMITTED 读未提交

* ISOLATION_READ_COMMITTED 读已提交  
	Oracle默认的事务隔离级别,只解决了脏读
	
* ISOLATION_REPEATABLE_READ 可重复读
	MySql默认的事务隔离级别,解决了脏读、不可重复读
	
* ISOLATION_SERIALIZABLE 串行化
	级别最高,效率最低,解决了脏读、不可重复读和虚读(幻读)
2)事务传播行为
  • 事务传播行为指的就是当一个业务方法【被】另一个业务方法调用时,应该如何进行事务控制。
参数说明
REQUIRED如果当前没有事务,就新建一个事务,如果已经存在一个事务中,加入到这个事务中。一般的选择(默认值)
SUPPORTS支持当前事务,如果当前没有事务,就以非事务方式执行(没有事务)
MANDATORY使用当前的事务,如果当前没有事务,就抛出异常
REQUERS_NEW新建事务,如果当前在事务中,把当前事务挂起
NOT_SUPPORTED以非事务方式执行操作,如果当前存在事务,就把当前事务挂起
NEVER以非事务方式运行,如果当前存在事务,抛出异常
NESTED如果当前存在事务,则在嵌套事务内执行。如果当前没有事务,则执行REQUIRED 类似的操作

在这里插入图片描述

* read-only(是否只读):建议查询时设置为只读

* timeout(超时时间):默认值是-1,没有超时限制。如果有,以秒为单位进行设置

2.2.3 TransactionStatus

  • TransactionStatus 接口提供的是事务具体的运行状态。
方法说明
boolean isNewTransaction()是否是新事务
boolean hasSavepoint()是否是回滚点
boolean isRollbackOnly()事务是否回滚
boolean isCompleted()事务是否完成

可以简单的理解三者的关系:事务管理器通过读取事务定义参数进行事务管理,然后会产生一系列的事务状态

2.2.4 实现代码

1)配置文件
<!--事务管理器交给IOC-->
<bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
	<property name="dataSource" ref="dataSource"/>
</bean>
2)业务层代码
@Service
public class AccountServiceImpl implements AccountService {
    @Autowired
    private AccountDao accountDao;
    @Autowired
    private PlatformTransactionManager transactionManager;
    @Override
    public void transfer(String outUser, String inUser, Double money) {
        // 创建事务定义对象
        DefaultTransactionDefinition def = new DefaultTransactionDefinition();
        // 设置是否只读,false支持事务
        def.setReadOnly(false);
        // 设置事务隔离级别,可重复读mysql默认级别
        def.setIsolationLevel(TransactionDefinition.ISOLATION_REPEATABLE_READ);
        // 设置事务传播行为,必须有事务
        def.setPropagationBehavior(TransactionDefinition.PROPAGATION_REQUIRED);
        // 配置事务管理器
        TransactionStatus status = transactionManager.getTransaction(def);
        try {
            // 转账
            accountDao.out(outUser, money);
            accountDao.in(inUser, money);
            // 提交事务
            transactionManager.commit(status);
        } catch (Exception e) {
            e.printStackTrace();
            // 回滚事务
            transactionManager.rollback(status);
        }
    }
}

2.2.5 知识小结

  • Spring中的事务控制主要就是通过这三个API实现的
* PlatformTransactionManager 负责事务的管理,它是个接口,其子类负责具体工作

* TransactionDefinition 定义了事务的一些相关参数

* TransactionStatus 代表事务运行的一个实时状态

理解三者的关系:事务管理器通过读取事务定义参数进行事务管理,然后会产生一系列的事务状态

2.3 基于XML的声明式事务控制【重点】

  • 在 Spring 配置文件中声明式的处理事务来代替代码式的处理事务。底层采用AOP思想来实现的

声明式事务控制明确事项:

  • 核心业务代码(目标对象) (切入点是谁?)
  • 事务增强代码(Spring已提供事务管理器))(通知是谁?)
  • 切面配置(切面如何配置?)

2.3.1 快速入门

需求

  • 使用spring声明式事务控制转账业务。
    步骤分析
1. 引入tx命名空间
2. 事务管理器通知配置
3. 事务管理器AOP配置
4. 测试事务控制转账业务代码

在这里插入图片描述

1)引入tx、aop命名空间
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:aop="http://www.springframework.org/schema/aop"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
                          http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd
                          http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd
                          http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd
	">
</beans>
2)事务管理器通知配置
<!--事务管理器对象-->
<bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
    <property name="dataSource" ref="dataSource" />
</bean>

<!--配置通知增强-->
<tx:advice id="txAdvice" transaction-manager="transactionManager">
    <!--定义事务的一些属性 * 表示挡墙任意名称的方法都是默认值-->
    <tx:attributes>
        <tx:method name="*"/>
    </tx:attributes>
</tx:advice>
3)事务管理器AOP配置
<!--aop配置:配置切面-->
<aop:config>
    <!--配置声明事务 使用的是aop:advisor-->
    <aop:advisor advice-ref="txAdvice" pointcut="execution(* com.myProject.service.AccountService.*(..))"></aop:advisor>
</aop:config>
4)spring核心配置文件
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:aop="http://www.springframework.org/schema/aop"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
                          http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd
                          http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd
                          http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd
">

    <!--IOC注解扫描-->
    <context:component-scan base-package="com.myProject"></context:component-scan>

    <!--引入properties文件-->
    <context:property-placeholder location="classpath:jdbc.properties"></context:property-placeholder>

    <!--配置dataSource-->
    <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">
        <property name="driverClassName" value="${jdbc.driverClassName}" />
        <property name="url" value="${jdbc.url}" />
        <property name="username" value="${jdbc.username}" />
        <property name="password" value="${jdbc.password}" />
    </bean>

    <!--jdbcTemplate-->
    <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
        <constructor-arg name="dataSource" ref="dataSource" />
    </bean>

    <!--事务管理器对象-->
    <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <property name="dataSource" ref="dataSource" />
    </bean>

    <!--配置通知增强-->
    <tx:advice id="txAdvice" transaction-manager="transactionManager">
        <tx:attributes>
            <!--
                name: 切点方法名称
                isolation: 事务的隔离级别
                propagation: 事务的传播行为
                read-only: 是否只读
                timeout:超时时间
            -->
            <tx:method name="transfer" isolation="REPEATABLE_READ" propagation="REQUIRED" read-only="false" timeout="-1" />
            <!--CRUD常用配置-->
            <!--save*:添加-->
            <tx:method name="save*" propagation="REQUIRED" />
            <!--delete:删除-->
            <tx:method name="delete" propagation="REQUIRED" />
            <!--update:修改-->
            <tx:method name="update" propagation="REQUIRED" />
            <!--find*:查询-->
            <tx:method name="find*" read-only="true" />
            <!--定义事务的一些属性 * 表示当前任意名称的方法都走默认配置-->
            <tx:method name="*" />
        </tx:attributes>
    </tx:advice>

    <!--aop配置:配置切面-->
    <aop:config>
        <!--配置声明事务 使用的是aop:advisor-->
        <aop:advisor advice-ref="txAdvice" pointcut="execution(* com.myProject.service.AccountService.*(..))"></aop:advisor>
    </aop:config>
</beans>
5)编写Account实体类
package com.myProject.domain;

public class Account {
    private Integer id;
    private String name;
    private Double money;

    @Override
    public String toString() {
        return "Account{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", money=" + money +
                '}';
    }

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Double getMoney() {
        return money;
    }

    public void setMoney(Double money) {
        this.money = money;
    }
}

6)编写AccountDao接口和实现类
package com.myProject.dao;

public interface AccountDao {
    /**
     * 转出操作
     */
    public void out(String outUser, Double money);

    /**
     * 转入操作
     */
    public void in(String inUser, Double money);
}

package com.myProject.dao.impl;

import com.myProject.dao.AccountDao;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.stereotype.Repository;
@Repository
public class AccountDaoImpl implements AccountDao {
    @Autowired
    private JdbcTemplate jdbcTemplate;

    @Override
    public void out(String outUser, Double money) {
        String sql = "update account set money = money - ? where name = ?";
        jdbcTemplate.update(sql, money, outUser);
    }

    @Override
    public void in(String inUser, Double money) {
        String sql = "update account set money = money + ? where name = ?";
        jdbcTemplate.update(sql, money, inUser);
    }
}

7)测试事务控制转账业务代码
package com.myProject.service;

public interface AccountService {
    /**
     * 转账方法
     */
    public void transfer(String outUser, String inUser, Double money);
}

package com.myProject.service.impl;

import com.myProject.dao.AccountDao;
import com.myProject.service.AccountService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

@Service
public class AccountServiceImpl implements AccountService {
    @Autowired
    private AccountDao accountDao;

    @Override
    public void transfer(String outUser, String inUser, Double money) {
        // 调用dao的out方法和in方法
        accountDao.out(outUser, money);

//        int i = 1/0;

        accountDao.in(inUser, money);
    }
}

8)编写测试代码
package com.myProject.test;

import com.myProject.service.AccountService;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration({"classpath:applicationContext.xml"})
public class AccountServiceImplTest {

    @Autowired
    private AccountService accountService;

    @Test
    public void testTransfer() {
        accountService.transfer("tom","jerry", 100d);
    }
}

2.3.2 事务参数的配置详解

<tx:method name="transfer" isolation="REPEATABLE_READ" propagation="REQUIRED" timeout="-1" read-only="false"/>

* name:切点方法名称

* isolation:事务的隔离级别

* propogation:事务的传播行为

* timeout:超时时间

* read-only:是否只读
2.3.3 CRUD常用配置
<!--配置通知增强-->
<tx:advice id="txAdvice" transaction-manager="transactionManager">
    <tx:attributes>
        <!--
            name: 切点方法名称
            isolation: 事务的隔离级别
            propagation: 事务的传播行为
            read-only: 是否只读
            timeout:超时时间
        -->
        <tx:method name="transfer" isolation="REPEATABLE_READ" propagation="REQUIRED" read-only="false" timeout="-1" />
        <!--CRUD常用配置-->
        <!--save*:添加-->
        <tx:method name="save*" propagation="REQUIRED" />
        <!--delete:删除-->
        <tx:method name="delete" propagation="REQUIRED" />
        <!--update:修改-->
        <tx:method name="update" propagation="REQUIRED" />
        <!--find*:查询-->
        <tx:method name="find*" read-only="true" />
        <!--定义事务的一些属性 * 表示当前任意名称的方法都走默认配置-->
        <tx:method name="*" />
    </tx:attributes>
</tx:advice>

2.3.4 知识小结

* 平台事务管理器配置

* 事务通知的配置

* 事务aop织入的配置

2.4 基于注解的声明式事务控制【重点】

2.4.1 常用注解

步骤分析

1. 修改service层,增加事务注解
2. 修改spring核心配置文件,开启事务注解支持
1)修改service层,增加事务注解
package com.myProject.service.impl;

import com.myProject.dao.AccountDao;
import com.myProject.service.AccountService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Isolation;
import org.springframework.transaction.annotation.Propagation;
import org.springframework.transaction.annotation.Transactional;

@Service
@Transactional
public class AccountServiceImpl implements AccountService {
    @Autowired
    private AccountDao accountDao;

    @Override
//    @Transactional(propagation = Propagation.REQUIRED, isolation = Isolation.REPEATABLE_READ, timeout = -1, readOnly = false )
    public void transfer(String outUser, String inUser, Double money) {
        // 调用dao的out方法和in方法
        accountDao.out(outUser, money);

//        int i = 1/0;

        accountDao.in(inUser, money);
    }
}
2)修改spring核心配置文件,开启事务注解支持
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:aop="http://www.springframework.org/schema/aop"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
                          http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd
                          http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd
                          http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd
">

    <!--IOC注解扫描-->
    <context:component-scan base-package="com.myProject"></context:component-scan>

    <!--引入properties文件-->
    <context:property-placeholder location="classpath:jdbc.properties"></context:property-placeholder>

    <!--配置dataSource-->
    <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">
        <property name="driverClassName" value="${jdbc.driverClassName}" />
        <property name="url" value="${jdbc.url}" />
        <property name="username" value="${jdbc.username}" />
        <property name="password" value="${jdbc.password}" />
    </bean>

    <!--jdbcTemplate-->
    <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
        <constructor-arg name="dataSource" ref="dataSource" />
    </bean>

    <!--事务管理器对象-->
    <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <property name="dataSource" ref="dataSource" />
    </bean>
    <!--开启事务的注解支持-->
    <tx:annotation-driven />
</beans>

2.4.2 纯注解

在这里插入图片描述

1)纯注解替换Spring的核心配置文件
  • 被纯注解替换,就可删除该核心配置文件
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:aop="http://www.springframework.org/schema/aop"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
                          http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd
                          http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd
                          http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd
">

    <!--IOC注解扫描-->
    <!--纯注解替换:@ComponentScan("com.myProject") // 包扫描-->
    <!--<context:component-scan base-package="com.myProject"></context:component-scan>-->


    <!--引入properties文件-->
    <!--纯注解替换:@PropertySource("classpath:jdbc.properties") // 引入properties文件-->
    <!--<context:property-placeholder location="classpath:jdbc.properties"></context:property-placeholder>-->

    <!--配置dataSource-->
    <!--纯注解替换:@Bean // 会把当前方法的返回值对象放进IOC容器中-->
    <!--<bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">-->
    <!--    <property name="driverClassName" value="${jdbc.driverClassName}" />-->
    <!--    <property name="url" value="${jdbc.url}" />-->
    <!--    <property name="username" value="${jdbc.username}" />-->
    <!--    <property name="password" value="${jdbc.password}" />-->
    <!--</bean>-->

    <!--jdbcTemplate-->
    <!--纯注解替换:@Bean-->
    <!--<bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">-->
    <!--    <constructor-arg name="dataSource" ref="dataSource" />-->
    <!--</bean>-->

    <!--事务管理器对象-->
    <!--纯注解替换:@Bean-->
    <!--<bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">-->
    <!--    <property name="dataSource" ref="dataSource" />-->
    <!--</bean>-->
    <!--开启事务的注解支持-->
    <!--纯注解替换:@EnableTransactionManagement // 事务的注解驱动-->
    <!--<tx:annotation-driven />-->
</beans>
2)核心配置类
package com.myProject.config;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Import;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;
import org.springframework.transaction.PlatformTransactionManager;
import org.springframework.transaction.annotation.EnableTransactionManagement;

import javax.sql.DataSource;

@Configuration // 声明该类为核心配置类
@ComponentScan("com.myProject") // 包扫描
@Import(DataSourceConfig.class) // 导入其他配置类
@EnableTransactionManagement // 事务的注解驱动
public class SpringConfig {
    @Bean
    public JdbcTemplate getJdbcTemplate(@Autowired DataSource dataSource) {
        JdbcTemplate jdbcTemplate = new JdbcTemplate(dataSource);
        return  jdbcTemplate;
    }

    @Bean
    public PlatformTransactionManager getPlatformTransactionMannger(@Autowired DataSource dataSource) {
        DataSourceTransactionManager dataSourceTransactionManager = new DataSourceTransactionManager(dataSource);
        return dataSourceTransactionManager;
    }
}

3)数据源配置类
package com.myProject.config;

import com.alibaba.druid.pool.DruidDataSource;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.PropertySource;

import javax.sql.DataSource;

@PropertySource("classpath:jdbc.properties") // 引入properties文件
public class DataSourceConfig {
    @Value("${jdbc.driverClassName}")
    private String driver;

    @Value("${jdbc.url}")
    private String url;

    @Value("${jdbc.username}")
    private String username;

    @Value("${jdbc.password}")
    private String password;

    @Bean // 会把当前方法的返回值对象放进IOC容器中
    public DataSource getDataSource() {
        DruidDataSource druidDataSource = new DruidDataSource();
        druidDataSource.setDriverClassName(driver);
        druidDataSource.setUrl(url);
        druidDataSource.setUsername(username);
        druidDataSource.setPassword(password);

        return druidDataSource;
    }
}

4)编写测试类
package com.myProject.test;

import com.myProject.config.SpringConfig;
import com.myProject.service.AccountService;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

@RunWith(SpringJUnit4ClassRunner.class)
//@ContextConfiguration({"classpath:applicationContext.xml"})
@ContextConfiguration(classes = SpringConfig.class)
public class AccountServiceImplTest {

    @Autowired
    private AccountService accountService;

    @Test
    public void testTransfer() {
        accountService.transfer("tom","jerry", 100d);
    }
}

2.4.3 知识小结

* 平台事务管理器配置(xml、注解方式)

* 事务通知的配置(@Transactional注解配置)

* 事务注解驱动的配置 <tx:annotation-driven/>、@EnableTransactionManagement

三 Spring集成web环境

3.1 ApplicationContext应用上下文获取方式

  • 应用上下文对象是通过 new ClasspathXmlApplicationContext(spring配置文件) 方式获取的,但是每次从容器中获得Bean时都要编写 new ClasspathXmlApplicationContext(spring配置文件) ,这样的弊端是配置文件加载多次,应用上下文对象创建多次。

解决思路分析:

3.2 Spring提供获取应用上下文的工具

  • 上面的分析不用手动实现,Spring提供了一个监听器ContextLoaderListener就是对上述功能的封装,该监听器内部加载Spring配置文件,创建应用上下文对象,并存储到ServletContext域中,提供了一个客户端工具WebApplicationContextUtils供使用者获得应用上下文对象。

所以我们需要做的只有两件事:

1. 在web.xml中配置ContextLoaderListener监听器(导入spring-web坐标)
2. 使用WebApplicationContextUtils获得应用上下文对象ApplicationContext

3.3 实现

在这里插入图片描述

1)导入Spring集成web的坐标

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.myProject</groupId>
    <artifactId>spring_web</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>

    <packaging>war</packaging>
    <dependencies>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>5.1.5.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-web</artifactId>
            <version>5.1.5.RELEASE</version>
        </dependency>
    </dependencies>
</project>

2)配置ContextLoaderListener监听器

  • web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">
    <servlet>
        <servlet-name>AccountServlet</servlet-name>
        <servlet-class>com.myProject.servlet.AccountServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>AccountServlet</servlet-name>
        <url-pattern>/AccountServlet</url-pattern>
    </servlet-mapping>

    <!--全局参数:指定applicationContext.xml文件路径-->
    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>classpath:applicationContext.xml</param-value>
    </context-param>
    
    <!--配置spring的监听器 contextLoaderListener-->
    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>
</web-app>

3)编写spring核心配置文件

  • applicationContext.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
                          http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd
">
    <!--配置account-->
    <bean id="account" class="com.myProject.domain.Account">
        <property name="id" value="1" />
        <property name="name" value="AA1" />
        <property name="money" value="100d" />
    </bean>
</beans>

4)编写Account实体类

package com.myProject.domain;

public class Account {
    private Integer id;
    private String name;
    private Double money;

    @Override
    public String toString() {
        return "Account{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", money=" + money +
                '}';
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Double getMoney() {
        return money;
    }

    public void setMoney(Double money) {
        this.money = money;
    }

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }
}

5)编写Account的servlet类

package com.myProject.servlet;

import com.myProject.domain.Account;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.web.context.support.WebApplicationContextUtils;

import javax.servlet.*;
import javax.servlet.http.*;
import java.io.IOException;

public class AccountServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//        ClassPathXmlApplicationContext classPathXmlApplicationContext = new ClassPathXmlApplicationContext("applicationContext.xml");
//        Account account = (Account)classPathXmlApplicationContext.getBean("account");
		
		// 通过WebApplicationContextUtils工具获得应用上下文对象
        ApplicationContext webApplicationContext = WebApplicationContextUtils.getWebApplicationContext(request.getServletContext());
        Account account = (Account) webApplicationContext.getBean("account");
        System.out.println(account );
    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doGet(request, response);
    }
}

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