MyBatis学习总结（二）---实例

为了对MyBatis有个初步了解，现做一个简单的增、删、改、查实例。了解涉及的文件与相关作用。

MySql创建friends表，以下是表的sql语句

 DROP TABLE IF EXISTS `friend`;

 CREATE TABLE `friend` (
   `id` bigint(20) NOT NULL,
   `friendName` varchar(50) NOT NULL,
   `sex` varchar(10) DEFAULT NULL,
   PRIMARY KEY (`id`)
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8;

创建一个MyBatisDemo工程

本人使用IDEA 2017创建该工程，也可以使用Eclipse创建。创建工程后，新增相关Package，导入相关的jar包。

目录说明：

com.yiming.demo，存放主类main，暂无写代码。

com.yiming.mapper，存放定义Mapper接口及映射文件，如：FriendMapper文件，friendMapper.xml文件。

com.yiming.pojo，存放实体类。

com.yiming.test，存放测试类，主要用于测试CRUD的方法。

com.yiming.untils，存放工具类，本工程只有：SqlSessionFactoryUntils

db.properties，为数据库属性文件。

mybatis-config.xml，为mybatis主要配置文件。

创建及配置db.properties,mybatis-config.xml二个文件

db.properties文件

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

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>
    <!--数据库配置文件-->
    <properties resource="db.properties"/>
    <!--别名-->
    <typeAliases>
        <typeAlias alias="friend" type="com.yiming.pojo.Friend"/>
    </typeAliases>
    <!--数据库环境-->
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
                <property name="driver" value="${database.driver}"/>
                <property name="url" value="${database.url}"/>
                <property name="username" value="${database.username}"/>
                <property name="password" value="${database.password}"/>
            </dataSource>
        </environment>
    </environments>
    <!--映射文件-->
    <mappers>
        <mapper resource="com/yiming/mapper/friendMapper.xml"/>
    </mappers>
</configuration>

创建friend表的实体类

Friend实体类

package com.yiming.pojo;

public class Friend {
    private long id;
    private String friendName;
    private String sex;

    public long getId() {
        return id;
    }

    public void setId(long id) {
        this.id = id;
    }

    public String getFriendName() {
        return friendName;
    }

    public void setFriendName(String friendName) {
        this.friendName = friendName;
    }

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }
}

创建FriendMapper文件及friendMapper.xml文件

FriendMapper文件

package com.yiming.mapper;

import com.yiming.pojo.Friend;

import java.util.List;

public interface FriendMapper {
    int inertFriend(Friend friend);
    int updateFriend(Friend friend);
    int deleteFriend(Friend friend);
    Friend getFriend(long id);
    List<Friend> getAllFrined(String friendName);
}

friendMapper.xml映射文件

<?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="com.yiming.mapper.FriendMapper">

    <insert id="inertFriend" parameterType="friend">
        insert into friend(id,friendName, sex) values(#{id},#{friendName}, #{sex})
    </insert>

    <delete id="deleteFriend" parameterType="long">
        delete from friend where id= #{id}
    </delete>

    <update id="updateFriend" parameterType="friend">
        update friend set friendName = #{friendName}, sex = #{sex} where id= #{id}
    </update>

    <select id="getFriend" parameterType="long" resultType="friend">
        select id,friendName, sex from friend where id = #{id}
    </select>

    <select id="getAllFrined" parameterType="string" resultType="friend">
        select id, friendName, sex from friend
        where friendName like concat('%', #{friendName}, '%')
    </select>
</mapper>

创建SqlSessionFactoryUtils类

SqlSessionFactoryUtils类文件

package com.yiming.untils;

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 java.io.IOException;
import java.io.InputStream;

public class SqlSessionFactoryUtils {
    private final static Class<SqlSessionFactoryUtils> LOCK = SqlSessionFactoryUtils.class;

    private static SqlSessionFactory sqlSessionFactory = null;

    private SqlSessionFactoryUtils() {
    }

    public static SqlSessionFactory getSqlSessionFactory() {
        synchronized (LOCK) {
            if (sqlSessionFactory != null) {
                return sqlSessionFactory;
            }
            String resource = "mybatis-config.xml";
            InputStream inputStream;
            try {
                inputStream = Resources.getResourceAsStream(resource);
                sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
            } catch (IOException e) {
                e.printStackTrace();
                return null;
            }
            return sqlSessionFactory;
        }
    }

    public static SqlSession openSqlSession() {
        if (sqlSessionFactory == null) {
            getSqlSessionFactory();
        }
        return sqlSessionFactory.openSession();
    }
}

创建FriendCRUD测试类

FriendCRUD

package com.yiming.test;

import com.yiming.mapper.FriendMapper;
import com.yiming.pojo.Friend;
import com.yiming.untils.SqlSessionFactoryUtils;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;

import java.util.List;

public class FriendCRUD {
    SqlSession session =null;
    //插入一对象测试
    @Test
    public void insertFriend( ){
        session = SqlSessionFactoryUtils.openSqlSession();
        Friend friend =new Friend();
        friend.setId(1L);
        friend.setFriendName("zhangsan");
        friend.setSex("man");
        try{
            FriendMapper friendMapper = session.getMapper(FriendMapper.class);
            friendMapper.inertFriend(friend);
            session.commit();
        }finally {
            if(session !=null){
                session.close();
            }
        }
    }
    @Test
    public void updateFriend(){
        session = SqlSessionFactoryUtils.openSqlSession();
        Friend friend = new Friend();
        friend.setId(1L);
        friend.setFriendName("zhangsanfeng");
        friend.setSex("man");
        try{
            FriendMapper friendMapper = session.getMapper(FriendMapper.class);
            friendMapper.updateFriend(friend);
            session.commit();
        }finally {
            if(session !=null){
                session.close();
            }
        }
    }

    @Test
    public void getFriend(){
        session = SqlSessionFactoryUtils.openSqlSession();
        try{
            FriendMapper friendMapper = session.getMapper(FriendMapper.class);
            Friend friend = friendMapper.getFriend(1L);
            System.out.print(friend.getFriendName());
        }finally {
            if(session !=null){
                session.close();
            }
        }
    }
    @Test
    public void getAllFriend(){
        session = SqlSessionFactoryUtils.openSqlSession();
        try{
            FriendMapper friendMapper = session.getMapper(FriendMapper.class);
            List<Friend> friendList = friendMapper.getAllFrined("zhangsanfeng");
            for(Friend friend : friendList){
                System.out.println(friend);
            }
        }finally {
            if(session !=null){
                session.close();
            }
        }
    }
    @Test
    public void deleteFriend(){
        session = SqlSessionFactoryUtils.openSqlSession();
        try{
            FriendMapper friendMapper = session.getMapper(FriendMapper.class);
            friendMapper.deleteFriend(1L);
            session.commit();
        }finally {
            if(session !=null){
                session.close();
            }
        }
    }
}