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
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 |
* 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
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
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
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);
}
}