實體類

package com.liuc.domain;

public class User {
	private int id;
	private String name;
	private Integer age;
	public String getName() {
		return name;
	}
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public void setName(String name) {
		this.name = name;
	}
	public Integer getAge() {
		return age;
	}
	public void setAge(Integer age) {
		this.age = age;
	}
	public User() {
	}

}
 

package com.liuc.dao;

import java.util.List;

import com.liuc.domain.User;


  
public interface UserMapper {  
    public User findById(String Id);  
    
    public List<User> getUserList();
}  

<?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">
<!--這塊等於dao介面的實現 namespace必須和介面的類路徑一樣 -->
<mapper namespace="com.liuc.dao.UserMapper">
	<!-- findById必須和介面中的方法名一樣 返回一個User 就是剛才的別名 如果不弄別名要連類路徑一起寫 麻煩 -->
	<select id="findById" parameterType="HashMap" resultType="User">
		select * from t_user where id=#{id}
	</select>
	<!--配置一個resultMap 指定返回的型別 -->
	<resultMap type="User" id="userListMap">
		<id column="id" property="id"/>
		<result column="name" property="name"/>
		<result column="age" property="age"/>
	</resultMap>
	<select id="getUserList" resultMap="userListMap">
		select * from t_user
	</select>
 

</mapper>  

List<User> usersList=userMapper.getUserList();