day39-Spring 18-Spring的JDBC模板：查询的操作

---

package cn.itcast.spring3.demo2;

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;

//public class UserDao {
    public class UserDao extends JdbcDaoSupport{
    /*在Dao层注入JDBC模板*/
/*    private JdbcTemplate jdbcTemplate;

    public void setJdbcTemplate(JdbcTemplate jdbcTemplate) {
        this.jdbcTemplate = jdbcTemplate;
    }*/
    public void add(User user){
         String sql = "insert into user values(null,?)";
         this.getJdbcTemplate().update(sql, user.getName());
     }
     public void update(User user){
         String sql = "update user set name = ? where id = ?";
         this.getJdbcTemplate().update(sql, user.getName(), user.getId());
     }
     public void delete(User user){
         String sql = "delete from user where id = ?";
         this.getJdbcTemplate().update(sql, user.getId());
     }

     public int findCount(){
        String sql = "select count(*) from user";
        return this.getJdbcTemplate().queryForInt(sql);

     }
     public String findNameById(int id){
        String sql = "select name from user where id = ?";
        return this.getJdbcTemplate().queryForObject(sql, String.class, id);

     }
     public User findById(int id){
        String sql = "select * from user where id = ?";
        User user = (User) this.getJdbcTemplate().queryForObject(sql, new UserRowMapper(), id);//rowMapper和DBUtils的Handler一样.
        //你需要自己去封装它.
        //只不过DBUtils给你提供了几个实现类,像beanHandler,beanListHandler,MapHandler,MapList.但是Jdbc模板没有提供实现类,要自己手动去封装它.
        return user;

     }
     public List<User> findAll(){
        String sql = "select * from user";
        return this.getJdbcTemplate().query(sql, new UserRowMapper());

     }
     //内部类
     class UserRowMapper implements RowMapper<User>{//泛型是User
        /**
         * rs:结果集.
         * rowNum:行号
         */
        public User mapRow(ResultSet rs, int rowNum) throws SQLException {
            // TODO Auto-generated method stub
            //现在呢它不用你去遍历结果集了,它已经把结果集的光标移向了某一行的具体的数据了.
            //你在mapRow()方法中不用自己去遍历结果集,这个mapRow()方法可以帮你遍历结果集.
            User user = new User();
            user.setId(rs.getInt("id"));
            user.setName(rs.getString("name"));
            return user;
        }

     }
}

package cn.itcast.spring3.demo2;

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 + "]";
}

}

package cn.itcast.spring3.demo2;

import java.util.List;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration("classpath:applicationContext.xml")
public class SpringTest2 {
    @Autowired
    @Qualifier("userDao")
    private UserDao userDao;
    @Test
    public void demo1(){
        //web层->业务层->Dao层
        User user = new User();
        user.setName("童童");
        //user.setName("小编");
        //user.setName("小胖");
        userDao.add(user);
    }
    @Test
    public void demo2(){
        //web层->业务层->Dao层
        User user = new User();
        user.setId(1);
        user.setName("小编");
        userDao.update(user);

    }
    @Test
    public void demo3(){
        //web层->业务层->Dao层
        User user = new User();
        user.setId(1);
        userDao.delete(user);

    }
    @Test
    public void demo4(){
        int count = userDao.findCount();
        System.out.println(count);
    }
    @Test
    public void demo5(){
        //String name = userDao.findNameById(2);//得到2号客户的名称
        String name = userDao.findNameById(3);//得到3号客户的名称
        System.out.println(name);
    }
    @Test
    public void demo6(){
        //String name = userDao.findNameById(2);//得到2号客户的User对象.
        //User user = userDao.findById(2);//得到2号客户的User对象.
        User user = userDao.findById(3);//得到3号客户的User对象.
        System.out.println(user);
    }
    @Test
    public void demo7(){
        //String name = userDao.findNameById(2);//得到2号客户的User对象.
        //User user = userDao.findById(2);//得到2号客户的User对象.
        List<User> list = userDao.findAll();
        for (User user : list) {
            System.out.println(user);
        }

    }
}

<?xml version="1.0" encoding="UTF-8"?>
<!-- 引入beans的头 -->
<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/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Spring默认的连接池 -->
    <!-- 这个类由Spring来帮我们创建,它默认情况下只创建一次,因为是单例的. -->
    <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">

        <property name="driverClassName" value="com.mysql.jdbc.Driver"></property>
        <property name="url" value="jdbc:mysql:///spring3_day02"></property>
        <property name="username" value="root"></property>
        <property name="password" value=""></property>

    </bean>
    <!-- 配置DBCP连接池 -->
    <bean id="dataSource1" class="org.apache.commons.dbcp.BasicDataSource">
        <property name="driverClassName" value="com.mysql.jdbc.Driver"></property>
        <property name="url" value="jdbc:mysql:///spring3_day02"></property>
        <property name="username" value="root"></property>
        <property name="password" value=""></property>

    </bean>
    <!--
    <bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
    <property name="location" value="classpath:jdbc.properties">--><!-- jdbc.properties也是在src下 --><!-- </property>
    </bean>
    -->
    <context:property-placeholder location="classpath:jdbc.properties"/>
    <!-- 配置C3P0连接池 -->
    <bean id="dataSource2" class="com.mchange.v2.c3p0.ComboPooledDataSource">
    <!--
        <property name="driverClass" value="com.mysql.jdbc.Driver"></property>
        -->
        <property name="driverClass" value="${jdbc.driver}"></property>
        <!--
        <property name="jdbcUrl" value="jdbc:mysql:///spring3_day02"></property>
        -->
        <property name="jdbcUrl" value="${jdbc.url}"></property>
        <!--
        <property name="user" value="root"></property>
        -->
        <property name="user" value="${jdbc.user}"></property>
        <!--
        <property name="password" value=""></property>
        -->
        <property name="password" value="${jdbc.password}"></property>

    </bean>
    <!-- 定义jdbctemplate -->
    <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
          <property name="dataSource" ref="dataSource2"></property><!-- 把上面定义好的连接池注入进来了 -->
    </bean>
    <bean id="userDao" class="cn.itcast.spring3.demo2.UserDao">
       <property name="jdbcTemplate" ref="jdbcTemplate"></property>

    </bean>
</beans>

jdbc.driver = com.mysql.jdbc.Driver
jdbc.url = jdbc:mysql:///spring3_day02
jdbc.user = root
jdbc.password =