MyBatis 3 入门

首先是数据源的配置，内容如下：

<?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/test" />
				<property name="username" value="root" />
				<property name="password" value="root" />
			</dataSource>
		</environment>
	</environments>
	<mappers>
		<mapper resource="com/mybatis/lin/user.xml" />
	</mappers>
</configuration>

 接下来是mapper的配置：

<?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.lin.UserMapper">
	<!-- 下面这段代码可有可无，如果没有的话可以在mapper类中通过注解的方式实现 -->
	<select id="getUser" parameterType="java.lang.String" resultType="com.mybatis.lin.User">
		select * from account   where username = #{username}
	</select>
</mapper>

 下面是Java类，bean如下：

package com.mybatis.lin;

public class User {
	private int id;
	private String username;
	private String password;
	
	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;
	}
	
}

 Mapper接口如下：

package com.mybatis.lin;

import org.apache.ibatis.annotations.Select;

public interface UserMapper {
	/**
	 * @Select("select * from account where username = #{username}")可有可无，如果在mapper resource文件中已经存在，可以去掉
	 * @param username
	 * @return
	 */
//	@Select("select * from account where username = #{username}")
	User getUser(String username);
}

 

 测试类如下：

package com.mybatis.lin;

import java.io.Reader;

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

public class Test {
	public static void main(String args[]) throws Exception {
		//读取数据源配置
		Reader reader = Resources.getResourceAsReader("dataResource.xml");
		//build SqlSessionFactory实例
		SqlSessionFactory sqlMapper = new SqlSessionFactoryBuilder().build(reader);
		//获取SqlSession
		SqlSession session = sqlMapper.openSession();
		//获取Mapper
		UserMapper userMapper = session.getMapper(UserMapper.class);
		//执行sql
		User user = userMapper.getUser("lin lvping");
		if (user != null) {
			System.out.println("username:"+user.getUsername()+", password:"+user.getPassword());
		}
	}
}

 测试结果如下：

username:lin lvping, password:123456

 

以上均参考自官方的guide文件：MyBatis-3-User-Guide.pdf，有空的同学可以仔细读读，很容易读懂的。