MyBatis 3 入门

猫猫1

　　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。