MyBatis 简单入门

　本文主要介绍了如何使用mybatis进行简单的数据库操作。本人使用的是mybatis3.05。

1.创建数据库表（User表）

CREATE TABLE `NewTable` (
`userId`  bigint(20) NOT NULL AUTO_INCREMENT ,
`userName`  varchar(30) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL ,
`password`  varchar(80) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL ,
`comment`  varchar(250) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL ,
PRIMARY KEY (`userId`),
UNIQUE INDEX `UQ_User_userName` (`userName`) USING BTREE
)

2.2. 创建实体类

package com.mybatis.config;

public class User {
    private int userId;
    private String userName;
    private String password;
    private String comment;
    public int getUserId() {
        return userId;
    }
    public void setUserId(int userId) {
        this.userId = userId;
    }
    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 getComment() {
        return comment;
    }
    public void setComment(String comment) {
        this.comment = comment;
    }
}

3. 定义数据访问接口

package com.mybatis.config;

import java.util.List;

public interface UserDao {
    
    public int insert(User user);
    
    public int update(User user);
    
    public int delete(String userName);
    
    public List<User> selectAll();
    
    public int countAll();
    
    public User findByUserName(String userName);
}

4.创建MyBatis映射文件（UserDaoMapper.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="com.mybatis.config.UserDao">
    <select id="countAll" resultType="int">
        select count(*) c from user;
    </select>
    
    <select id="selectAll" resultType="com.mybatis.config.User">
        select * from user order by userName asc
    </select>
    
    <insert id="insert" parameterType="com.mybatis.config.User">
        insert into user(userName,password,comment) values(#{userName},#{password},#{comment})
    </insert>
    
    <update id="update" parameterType="com.mybatis.config.User">
        update user set userName=#{userName},password=#{password},comment=#{comment} where userName=#{userName}
    </update>
    
    <delete id="delete" parameterType="int">
        delete from user where userName=#{userName}
    </delete>
    
    <select id="findByUserName" parameterType="String" resultType="com.mybatis.config.User">
        select * from user where userName=#{userName}
    </select>
</mapper>

5. 创建mybatis配置文件

<?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>
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC" />
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver" />
                <property name="url" value="jdbc:mysql://localhost:3306/hlp?useUnicode=true&characterEncoding=UTF-8&zeroDateTimeBehavior=convertToNull" />
                <property name="username" value="root" />
                <property name="password" value="1234" />
            </dataSource>
        </environment>
    </environments>
    <mappers>
        <mapper resource="com/mybatis/config/UserDaoMapper.xml"/>
    </mappers>
</configuration>

6. 编写测试代码

package com.mybatis.config;

import java.io.Reader;
import java.util.Iterator;
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;

public class UserDaoTest {
    @Test
    public void userDaoTest() throws Exception
    {
        String resource = "MyBatis-Configuration.xml";
        Reader reader = Resources.getResourceAsReader(resource);
        SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
        SqlSessionFactory factory = builder.build(reader);
        
        SqlSession session = factory.openSession();
        UserDao userDao = session.getMapper(UserDao.class);
        
        User user = new User();
        user.setUserName("hongye");
        user.setPassword("123456");
        user.setComment("备注");
        
        userDao.insert(user);
        System.out.println("记录条数："+userDao.countAll());
        
        List<User> users = userDao.selectAll();
        Iterator<User> iter = users.iterator();
        while(iter.hasNext()){
            User u = iter.next();
            System.out.println("用户名："+u.getUserName()+"密码："+u.getPassword());
        }
        
        user.setComment("comment");
        userDao.update(user);
        User u = userDao.findByUserName("hongye");
        System.out.println(u.getComment());
        
        userDao.delete("hongye");
        System.out.println("记录条数："+userDao.countAll());
        
        session.commit();
        session.close();
    }
}