01—mybatis开山篇

什么是 MyBatis ？

       MyBatis 是支持定制化 SQL、存储过程以及高级映射的优秀的持久层框架。MyBatis 避免了几乎所有的 JDBC 代码和手动设置参数以及获取结果集。MyBatis 可以对配置和原生Map使用简单的 XML 或注解，将接口和 Java 的 POJOs(Plain Old Java Objects,普通的 Java对象)映射成数据库中的记录。

 

mybatis文档

       http://www.mybatis.org/mybatis-3/zh/index.html

 

mybatis入门程序

目录结构

1.创建数据库和数据表，数据库采用mysql

CREATE TABLE `tb_user` (
  `Id` BIGINT(20) NOT NULL AUTO_INCREMENT,
  `Username` VARCHAR(50) COLLATE utf8_bin DEFAULT NULL,
  `Password` VARCHAR(50) COLLATE utf8_bin DEFAULT NULL,
  `Nickname` VARCHAR(50) COLLATE utf8_bin DEFAULT NULL,
  `Type` INT(11) DEFAULT NULL,
  PRIMARY KEY (`Id`)
)

　　

2.创建一个普通的java project，在项目上右建新建一个文件夹(folder) lib，将jar导入，引用相关jar。

我这里一共用了三个jar，分别是：mybatis-3.1.1.jar、mysql-connector-java-5.1.17-bin.jar、junit-4.9.jar

 

3.创建model和xml文件

User.java

package org.mybatis.test.model;

public class User {
    private int id;
    private String username;
    private String password;
    private String nickname;
    private int type;
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getUsername() {
        return username;
    }
    public void setUsername(String username) {
        this.username = username;
    }
    public String getPassword() {
        return password;
    }
    public void setPassword(String password) {
        this.password = password;
    }
    public String getNickname() {
        return nickname;
    }
    public void setNickname(String nickname) {
        this.nickname = nickname;
    }
    public int getType() {
        return type;
    }
    public void setType(int type) {
        this.type = type;
    }
}

User.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper
    PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
    "http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<mapper namespace="org.mybatis.test.model.User">
    <insert id="add" parameterType="org.mybatis.test.model.User">
        insert into tb_user (username,password,nickname,type)
            value(#{username},#{password},#{nickname},#{type})
    </insert>
    <update id="update" parameterType="org.mybatis.test.model.User">
        update tb_user set password=#{password},nickname=#{nickname},type=#{type} where id=#{id}
    </update>

    <delete id="delete" parameterType="int">
        delete from tb_user where id=#{id}
    </delete>

    <select id="load" parameterType="int" resultType="org.mybatis.test.model.User">
        select * from tb_user where id=#{id}
    </select>

    <select id="list" resultType="org.mybatis.test.model.User">
        select * from tb_user
    </select>
</mapper>

4.mybatis-config.xml文件

      1.先添加jdbc.properties文件

username=root
password=123456
url=jdbc:mysql://localhost:3306/mybatistest
driver=com.mysql.jdbc.Driver

       2.添加mybatis-config.xml文件

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
    "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <properties resource="jdbc.properties"/>
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC" />
            <dataSource type="POOLED">
                <property name="driver" value="${driver}" />
                <property name="url" value="${url}" />
                <property name="username" value="${username}" />
                <property name="password" value="${password}" />
            </dataSource>
        </environment>
    </environments>
    <!-- 将mapper文件加入到配置文件中 -->
    <mappers>
        <mapper resource="org/mybatis/test/model/User.xml"/>
    </mappers>
</configuration>

5.junit测试

TestMyBatis.java

package org.mybatis.test.test;

import java.io.IOException;
import java.io.InputStream;
import java.util.List;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.Test;
import org.mybatis.test.model.User;

public class TestMyBatis {
    @Test
    public void testInsertUser() {
        try {
            //1、创建配置文件(mybatis-config.xml)的输入流
            InputStream is = Resources.getResourceAsStream("mybatis-config.xml");
            //2、创建SQLSessionFactory
            SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(is);
            //3、创建SQLSessioin
            SqlSession session = factory.openSession();
            //4、调用mapper文件插入数据（调用之前需要将mapper文件加入到mybatis-config.xml中）
            User u = new User();
            u.setNickname("小助理001");
            u.setPassword("123456");
            u.setUsername("zhuli001");
            u.setType(0);
            session.insert("org.mybatis.test.model.User.add", u);
            session.commit();
            session.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    @Test
    public void testUpdateUser() {
        try {
            InputStream is = Resources.getResourceAsStream("mybatis-config.xml");
            SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(is);
            SqlSession session = factory.openSession();
            User u = new User();
            u.setNickname("小猪手001");
            u.setPassword("111111");
            u.setType(0);
            u.setUsername("zhushou");
            u.setId(1);
            session.update("org.mybatis.test.model.User.update",u);
            session.commit();
            session.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    @Test
    public void testDeleteUser() {
        try {
            InputStream is = Resources.getResourceAsStream("mybatis-config.xml");
            SqlSessionFactory f = new SqlSessionFactoryBuilder().build(is);
            SqlSession session = f.openSession();
            session.delete("org.mybatis.test.model.User.delete",2);
            session.commit();
            session.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    @Test
    public void testLoad() {
        SqlSession session = null;
        try{
            InputStream is = Resources.getResourceAsStream("mybatis-config.xml");
            SqlSessionFactory f = new SqlSessionFactoryBuilder().build(is);
            session = f.openSession();
            User u = (User)session.selectOne(User.class.getName()+".load", 1);
            System.out.println(u.getNickname());
        }
        catch (IOException e) {
            e.printStackTrace();
        }
        finally {
            session.close();
        }
    }

    @Test
    public void testList() {
        SqlSession session = null;
        try{
            InputStream is = Resources.getResourceAsStream("mybatis-config.xml");
            SqlSessionFactory f = new SqlSessionFactoryBuilder().build(is);
            session = f.openSession();
            List<User> us = session.selectList(User.class.getName()+".list", null);
            for (User u : us) {
                 System.out.println(u.getId()+"-"+u.getUsername()+"-"+u.getNickname()); //逐个输出数组元素的值
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
        finally {
            session.close();
        }
    }

}

 代码下载