一共有两个办法。1，修改sql语句。2，使用<resultMap>映射类属性名和字段的关系。xml方式和annotation注解都是相同的。
全部代码下载地址：https://git.oschina.net/zhuhongliang/SimpleMybatisDemo/tree/differentName
这个demo还是在前几篇的基础上修改来的，下面放代码：
先看下mysql数据库的字段名和实体类的属性名：
User.java
package com.zhl.obj;
public class User {
private int id_a;
private String namea;
private int newAgehehe;
public int getId_a() {
return id_a;
}
public void setId_a(int id_a) {
this.id_a = id_a;
}
public String getNamea() {
return namea;
}
public void setNamea(String namea) {
this.namea = namea;
}
public int getNewAgehehe() {
return newAgehehe;
}
public void setNewAgehehe(int newAgehehe) {
this.newAgehehe = newAgehehe;
}
public String toString(){
return "User [id= "+id_a+",name= "+namea+",age= "+newAgehehe+"]";
}
}
下面先看下xml文件的修改：
<?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.zhl.mapping.userMapper">
<!-- 没有修改sql语句，resultMap的值是下面resultMap标签的id值 -->
<!-- 查一个 -->
<select id="getUser" parameterType="int" resultMap="getUserMap">
select * from users where id = #{id_a}
</select>
<!--这里用resultMap标签 映射user类和数据库字段 -->
<resultMap type="User" id="getUserMap">
<!-- 用id属性来映射主键字段 -->
<id property="id_a" column="id"/>
<!-- 用result属性来映射非主键字段 -->
<result property="newAgehehe" column="age"/>
<result property="namea" column="name"/>
</resultMap>
<!-- 下面的都没什么修改，sql语句的变量要写实体类的属性：#{namea}, #{newAgehehe} -->
<!-- 增 -->
<insert id="addUser" parameterType="User">
insert into users(name, age) values(#{namea}, #{newAgehehe})
</insert>
<!-- 删 -->
<delete id="deleteUser" parameterType="String">
delete from users where name =#{namea}
</delete>
<!-- 改 -->
<update id="updateUser" parameterType="User">
update users set name=#{namea}, age =#{newAgehehe} where id=#{id_a}
</update>
<!-- 直接修改sql语句 -->
<!-- 查全部 -->
<select id="getAll" resultType="User">
select id id_a, name namea, age newAgehehe from users
</select>
</mapper>
下面看看annotation版本的代码：
package com.zhl.mapping;
import java.util.List;
import org.apache.ibatis.annotations.Delete;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Result;
import org.apache.ibatis.annotations.Select;
import org.apache.ibatis.annotations.Update;
import org.apache.ibatis.annotations.Results;
import com.zhl.obj.User;
public interface UserMapperI {
@Insert("insert into users (name, age) values(#{namea}, #{newAgehehe})")
public int addUser(User user);
//直接修改sql语句
@Select("select id id_a, name namea, age newAgehehe from users where id = #{id_a}")
public User getUser(int id);
//使用Result映射实体类的属性和数据库的字段
@Select("select * from users")
@Results({
@Result(id=true,column="id",property="id_a"),
@Result(column="name",property="namea"),
@Result(column="age",property="newAgehehe")
})
public List getAll();
@Update("update users set name= #{namea}, age=#{newAgehehe} where id= #{id_a}")
public int updateUser (User user);
@Delete("delete from users where name = #{namea}")
public int deleteUser(String name);
}
就这么简单，全部代码下载地址：https://git.oschina.net/zhuhongliang/SimpleMybatisDemo/tree/differentName