【转】Spring + JdbcTemplate + JdbcDaoSupport

首先，数据库是这样的，很简单。

当然，要引入spring的包，这里我全部导入了，省事。

applicationContext.xml是这样的：

 

<?xml version="1.0" encoding="UTF-8"?>
<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-2.5.xsd">

    <bean id="test" class="jdbc.Test">
    <property name="dataSource" ref="dataSource"></property>
    </bean>

    <bean id="dataSource"
        class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="driverClassName" value="com.mysql.jdbc.Driver" />
        <property name="url" value="jdbc:mysql://localhost:3306/testspring" />
        <property name="username" value="root" />
        <property name="password" value="" />
    </bean>

</beans>

 

User.java是这样的：

 

package jdbc;

public class User {
    private int id;
    private String name;
    private String password;

    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getPassword() {
        return password;
    }
    public void setPassword(String password) {
        this.password = password;
    }

}

 

下面来对比一下三种写法：

1、spring

 

package jdbc;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.SQLException;

import javax.sql.DataSource;

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

public class Test {
    private DataSource dataSource;

    public void setDataSource(DataSource dataSource) {
        this.dataSource = dataSource;
    }

    public void insert(User u) {
        String sql = "insert into _user " + "values(null, ?, ?)";//普通的sql语句
        Connection conn = null;

        try {
            conn = dataSource.getConnection();
            PreparedStatement ps = conn.prepareStatement(sql);
            ps.setString(1, u.getName());
            ps.setString(2, u.getPassword());
            ps.executeUpdate();
            ps.close();
        } catch (SQLException e) {
            throw new RuntimeException(e);
        } finally {
            if (conn != null) {
                try {
                    conn.close();
                } catch (SQLException e) {
                }
            }
        }
    }

    public static void main(String[] args) {
        ApplicationContext ctx = new ClassPathXmlApplicationContext(
                "applicationContext.xml");
        Test t = (Test) ctx.getBean("test");

        User u = new User();
        u.setName("dd");
        u.setPassword("dd");
        t.insert(u);
    }
}

运行结果是这样的：

 

2、JdbcTemplate 

 

package jdbc;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.SQLException;

import javax.sql.DataSource;

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

public class Test {
    private DataSource dataSource;

    public void setDataSource(DataSource dataSource) {
        this.dataSource = dataSource;
    }

    public void insert(User u) {
        String sql = "insert into _user " + "values(null, ?, ?)";//普通的sql语句
        JdbcTemplate template = new JdbcTemplate(dataSource);
        template.update(sql, new Object[]{u.getName(), u.getPassword()});
    }

    public static void main(String[] args) {
        ApplicationContext ctx = new ClassPathXmlApplicationContext(
                "applicationContext.xml");
        Test t = (Test) ctx.getBean("test");

        User u = new User();
        u.setName("dd");
        u.setPassword("dd");
        t.insert(u);
    }
}

可以看得出简单了很多，不用Connection了。

 

3、JdbcDaoSupport

这个更简单，不用new JdbcTemplate了。

 

package jdbc;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.jdbc.core.support.JdbcDaoSupport;

public class Test extends JdbcDaoSupport {
    //JdbcDaoSupport类已经有了public final void setDataSource(DataSource dataSource)了
    //不用重写也不能重写

    public void insert(User u) {
        String sql = "insert into _user " + "values(null, ?, ?)";//普通的sql语句
        this.getJdbcTemplate().update(sql, new Object[]{u.getName(), u.getPassword()});
    }

    public static void main(String[] args) {
        ApplicationContext ctx = new ClassPathXmlApplicationContext(
                "applicationContext.xml");
        Test t = (Test) ctx.getBean("test");

        User u = new User();
        u.setName("dd");
        u.setPassword("dd");
        t.insert(u);
    }
}

三种方法哪一种更简单一目了然。