Spring框架--spring的jdbcTemlate

一、Spring对不同的持久化支持

Spring为各种支持的持久化技术，都提供了简单操作的模板和回调

ORM持久化技术	模板类
JDBC	org.springframework.jdbc.core.JdbcTemplate
Hibernate5.0	org.springframework.orm.hibernate5.HibernateTemplate
IBatis(MyBatis)	org.springframework.orm.ibatis.SqlMapClientTemplate
JPA	org.springfrmaework.orm.jpa.JpaTemplate

其实Spring的JDBCTemplate有点像DBUtils，但是有时候还没有DBUitls好用。下面我们就来学习一下使用SpringJDBCTemplate来玩一下CRUD。

二、实现jdbcTemlate的CRDU

1.引入依赖：

<?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">
    <parent>
        <artifactId>SpringTest</artifactId>
        <groupId>com.tulun</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>jdbctemlate</artifactId>
    <packaging>jar</packaging>

    <dependencies>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>4.1.7.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>4.1.7.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-tx</artifactId>
            <version>4.1.7.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.39</version>
        </dependency>
    </dependencies>


</project>

2.xml配置文件：

<?xml version="1.0" encoding="UTF-8"?>
<!--根标签-->
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">

    <!--配置jdbctemlate-->
    <bean id="jdbcTemlate" class="org.springframework.jdbc.core.JdbcTemplate">
        <property name="dataSource" ref="dataSource"></property>
    </bean>
    
    <!--配置数据源-->
    <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="driverClassName" value="com.mysql.jdbc.Driver"></property>
        <property name="url" value="jdbc:mysql://localhost:3306/eesy"></property>
        <property name="username" value="root"></property>
        <property name="password" value="123"></property>
    </bean>
</beans>

3.跟数据库映射的Account类：

import java.io.Serializable;

public class Account implements Serializable {
    private Integer id;
    private String name;
    private Float 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 Float getMoney() {
        return money;
    }

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

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

4.测试类：

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.RowMapper;

import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.List;

public class JdbctemlateDemo3 {
    public static void main(String[] args) {
        //1.获取容器
        ApplicationContext ac = new ClassPathXmlApplicationContext("bean.xml");
        //2.获取对象
        JdbcTemplate jt = ac.getBean("jdbcTemlate", JdbcTemplate.class);

        //执行操作
        //保存
        //jt.update("insert into account(name,money)values(?,?)","eee",3333f);

        //更新
        //jt.update("update account set name=?,money=? where id=?","test",4567,2);
        //删除

        //jt.update("delete from account where id=?",2);
        //查询所有
        //List<Account> accountList = jt.query("select * from account where money > ?",new AccountRowMapper(),1000f);
        /*List<Account> accountList = jt.query("select * from account where money > ?",new BeanPropertyRowMapper<Account>(Account.class),1000f);

        for (Account account : accountList){
            System.out.println(account);
        }*/
        //查询一个
        List<Account> accounts = jt.query("select * from account where id=?",new BeanPropertyRowMapper<Account>(Account.class),0);
        System.out.println(accounts.isEmpty()?"没有内容":accounts.get(0));

        //查询返回一行一个（使用聚合函数，）
        /*Long count = jt.queryForObject("select count(*) from account where money > ?",Long.class,1000f);
        System.out.println(count);*/
    }
}

上面我们测试了增删改查的方法，我们展示一个查询一个的方法：

**改进：**在实际开发中，我们不可能将方法和sql语句写在main函数中，这只是一个测试类。我们要想代码的可利用开发，和方便测试和重写，就必须使用spring为我们提供的便利条件，将CRDU持久化。

1.首先还是需要一个dao层的持久层接口方法：

public interface AccountDao {
    /**
     * 根据id查询账户
     * @param id
     * @return
     */
    Account findAccountById(Integer id);

    /**
     * 根据名称查询账户
     * @param name
     * @return
     */
    Account findAccountByName(String name);

    /**
     * 更新账户
     */
    void updateAccount(Account account);
}

2.持久层的实现类：

import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;

public class AccountDaoImpl implements AccountDao {
    private JdbcTemplate jdbcTemplate;

    public void setJdbcTemplate(JdbcTemplate jdbcTemplate) {
        this.jdbcTemplate = jdbcTemplate;
    }

    public Account findAccountById(Integer id) {
        List<Account> accounts = jdbcTemplate.query("select * from account where id=?",new BeanPropertyRowMapper<Account>(Account.class),id);
        return accounts.isEmpty()?null:accounts.get(0);
    }

    public Account findAccountByName(String name) {
        List<Account> accounts = jdbcTemplate.query("select * from account where name=?",new BeanPropertyRowMapper<Account>(Account.class),name);
        if (accounts.isEmpty()){
            return null;
        }
        if (accounts.size() > 1){
            throw new RuntimeException("结果集不唯一");
        }
        return accounts.get(0);
    }

    public void updateAccount(Account account) {
        jdbcTemplate.update("update account set name=?,money=? where id=?",account.getName(),account.getMoney(),account.getId());
    }
}

3.把AccountDao注册到xml配置文件中，让spring IOC容器进行管理：

<!--配置账户持久层-->
    <bean id="accountDao" class="com.dao.impl.AccountDaoImpl">
        <property name="jdbcTemplate" ref="jdbcTemlate"></property>
    </bean>

4.测试类：

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class JdbctemlateDemo4 {
    public static void main(String[] args) {
        ApplicationContext ac = new ClassPathXmlApplicationContext("bean.xml");
        AccountDao accountDao = ac.getBean("accountDao",AccountDao.class);

        Account account = accountDao.findAccountById(2);
        System.out.println(account);

        account.setMoney(10000f);
        accountDao.updateAccount(account);
    }
}

运行结果：