Spring整合JDBCTemplate

Spring整合JDBC

Spring提供了很多模板整合Dao技术，包括JDBC,Hibernate，MyBatis，JPA等

spring中提供了一个可以操作数据库的对象.对象封装了jdbc技术，JDBCTemplate是JDBC的一个模板对象，与DBUtils中的QueryRunner非常相似。本文就JDBCTemplate进行相应的阐述及代码演示

准备工作

• 表设计
  
• 准备User实体类

package cn.itcast.bean;

public class User {
    private Integer id;
    private String name;
    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;
    }
    @Override
    public String toString() {
        return "User [id=" + id + ", name=" + name + "]";
    }
}

• 导包
  基础包4个+日志包2个+spring-test，spring-aop，junit4类库+c3p0连接池，JDBC驱动+spring-jdbc，spring-tx事务
  

• 编写Dao层代码

//Dao层接口
package cn.itcast.a_jdbctemplate;
import java.util.List;
import cn.itcast.bean.User;

public interface UserDao {
    //增
    void save(User u);
    //删
    void delete(Integer id);
    //改
    void update(User u);
    //通过ID查找
    User getById(Integer id);
    //查找总记录数
    int getTotalCount();
    //查询所有
    List<User> getAll();
}

Spring中提供了一个JdbcDaoSupport类，Dao层继承该类后，不需要手动准备JDBC模板，直接根据DataSource创建JDBC模板，从父类方法中直接获得JDBCTemplate对象。

//Dao层实现类
package cn.itcast.a_jdbctemplate;

import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.List;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.RowMapper;
import org.springframework.jdbc.core.support.JdbcDaoSupport;

import cn.itcast.bean.User;
//使用JDBC模板实现增删改查，继承了JdbcDaoSupport类。
public class UserDaoImpl extends JdbcDaoSupport implements UserDao {
    @Override
    public void save(User u) {
        String sql = "insert into t_user values(null,?) ";
        super.getJdbcTemplate().update(sql, u.getName());
    }
    @Override
    public void delete(Integer id) {
        String sql = "delete from t_user where id = ? ";
        super.getJdbcTemplate().update(sql,id);
    }
    @Override
    public void update(User u) {
        String sql = "update  t_user set name = ? where id=? ";
        super.getJdbcTemplate().update(sql, u.getName(),u.getId());
    }
    @Override
    public User getById(Integer id) {
        String sql = "select * from t_user where id = ? ";
        return super.getJdbcTemplate().queryForObject(sql,new RowMapper<User>(){
            @Override
            public User mapRow(ResultSet rs, int arg1) throws SQLException {
                User u = new User();
                u.setId(rs.getInt("id"));
                u.setName(rs.getString("name"));
                return u;
            }}, id);

    }
    @Override
    public int getTotalCount() {
        String sql = "select count(*) from t_user  ";
        Integer count = super.getJdbcTemplate().queryForObject(sql, Integer.class);
        return count;
    }

    @Override
    public List<User> getAll() {
        String sql = "select * from t_user  ";
        List<User> list = super.getJdbcTemplate().query(sql, new RowMapper<User>(){
            @Override
            public User mapRow(ResultSet rs, int arg1) throws SQLException {
                User u = new User();
                u.setId(rs.getInt("id"));
                u.setName(rs.getString("name"));
                return u;
            }});
        return list;
    }
}

• 配置文件
  通过读取外部的Properties文件，来加载连接数据库的参数值

jdbc.jdbcUrl=jdbc:mysql:///hibernate_32
jdbc.driverClass=com.mysql.jdbc.Driver
jdbc.user=root
jdbc.password=1234

配置文件

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.springframework.org/schema/beans" xmlns:context="http://www.springframework.org/schema/context" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.2.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.2.xsd ">

<!-- 指定spring读取db.properties配置 -->
<context:property-placeholder location="classpath:db.properties"  />

<!-- 1.将连接池放入spring容器 -->
<bean name="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource" >
    <property name="jdbcUrl" value="${jdbc.jdbcUrl}" ></property>
    <property name="driverClass" value="${jdbc.driverClass}" ></property>
    <property name="user" value="${jdbc.user}" ></property>
    <property name="password" value="${jdbc.password}" ></property>
</bean>


<!-- 2.将JDBCTemplate放入spring容器
<bean name="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate" >
    <property name="dataSource" ref="dataSource" ></property>
</bean> -->

<!-- 3.将UserDao放入spring容器 -->
<bean name="userDao" class="cn.itcast.a_jdbctemplate.UserDaoImpl" >
    <!-- 继承了JdbcDaoSupport，就不需要注入jdbcTemplate，直接注入连接池就可以了 -->
    <!-- <property name="jt" ref="jdbcTemplate" ></property> -->
    <property name="dataSource" ref="dataSource" ></property>
</bean>
</beans>

测试

package cn.itcast.a_jdbctemplate;

import javax.annotation.Resource;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

import cn.itcast.bean.User;

//演示JDBC模板
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration("classpath:applicationContext.xml")
public class Demo {
    @Resource(name="userDao")
    private UserDao ud;

    @Test
    public void fun1() throws Exception{
        User u = new User();
        u.setName("tom");
        ud.save(u);
    }
    @Test
    public void fun2() throws Exception{
        User u = new User();
        u.setId(2);
        u.setName("jack");
        ud.update(u);

    }
    @Test
    public void fun3() throws Exception{
        ud.delete(2);
    }
    @Test
    public void fun4() throws Exception{
        System.out.println(ud.getTotalCount());
    }
    @Test
    public void fun5() throws Exception{
        System.out.println(ud.getById(1));
    }
    @Test
    public void fun6() throws Exception{
        System.out.println(ud.getAll());
    }
}