《Java EE核心框架实战》—— 2.3 < resultMap >标签

2.3 < resultMap >标签

如果数据表中字段的名称和Java实体类中属性的名称不一致，就要使用< resultMap>标签来进行映射。

创建名为resultMapTest的Java项目，映射配置文件userinfoMapping.xml代码如下。

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "mybatis-3-mapper.dtd">
<mapper namespace="mybatis.testcurd">
 <resultMap type="entity.Userinfo" id="userinfo">
  <result column="id" property="idghy" />
  <result column="username" property="usernameghy" />
  <result column="password" property="passwordghy" />
  <result column="age" property="ageghy" />
  <result column="insertdate" property="insertdateghy" />
 </resultMap>
 <select id="getUserinfoAll" resultMap="userinfo">
  select * from
  userinfo
 </select>
</mapper>```
实体类Userinfo.java的结构如图2-1所示。

<div style="text-align: center"><img src="https://yqfile.alicdn.com/eb1953f6ef12b87f9406f28874dcce16a0abac7f.png" width="" height="">
</div>

创建Run.java运行类，核心代码如下。

public class Run {
public static void main(String[] args) {
try {
String resource = "mybatis-config.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder()

 .build(inputStream);

SqlSession sqlSession = sqlSessionFactory.openSession();
List listUserinfo = sqlSession

 .selectList("getUserinfoAll");

for (int i = 0; i < listUserinfo.size(); i++) {

Userinfo userinfo = listUserinfo.get(i);
System.out.println(userinfo.getIdghy() + " "
  + userinfo.getUsernameghy() + " "
  + userinfo.getPasswordghy() + " "
  + userinfo.getAgeghy() + " "
  + userinfo.getInsertdateghy());

}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}`
运行程序后的结果如图2-2所示。

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