Mybatis查询语句返回对象和泛型集合的操作

package cn.et.mybatis.lesson03;

import java.util.List;

import org.apache.ibatis.annotations.Result;

import org.apache.ibatis.annotations.Results;

import org.apache.ibatis.annotations.Select;

public interface EmpMapper {

  /**

   * 查询单条数据，

   *  每一列的列名都会去Emp实体类中去匹配对应的属性

   *   匹配时会把二边都转为小字母进行匹配

   *   匹配成功就会调用Emp实体类中对象的set方法

   *

   * 如果列名和Emp的属性匹配不上，

   *  1.为查询结果的列设置一个别名

   *      2.将列名ename和属性ename1建立一个关系 单个属性建立关系

   *

   *   column是不区分大小写的，property是区分大小写的

   * @return

   */

  @Results (

    {

     @Result (column= "ename" ,property= "ename1" ),

     @Result (column= "empNo" ,property= "empNo1" ),

     @Result (column= "sal" ,property= "sal1" ),

    }

  )

  @Select ( "select * from emp where empno=#{0}" )

  public Emp queryEmpByEmpNo(String empNo);

  /**

   * 查询出多条数据，每一条数据都是一个Emp对象

   * 每一列的列名都会去Emp实体类中去匹配对应的属性

   *   匹配时会把二边都转为小字母进行匹配

   *   匹配成功就会调用Emp实体类中对象的set方法

   * 如果没有一条数据匹配成功，则不会创建Emp对象

   * @param empNo

   * @return

   */

  @Results (

    {

     @Result (column= "ename" ,property= "ename1" ),

     @Result (column= "empNo" ,property= "empNo1" ),

     @Result (column= "sal" ,property= "sal1" ),

    }

  )

  @Select ( "select * from emp" )

  public List<Emp> queryEmp();

}

package cn.et.mybatis.lesson03;

import java.io.InputStream;

import java.util.List;

import org.apache.ibatis.session.SqlSession;

import org.apache.ibatis.session.SqlSessionFactory;

import org.apache.ibatis.session.SqlSessionFactoryBuilder;

import org.junit.Test;

public class TestMybatis {

  public static SqlSession getSession(){

   String resource = "/cn/et/mybatis/lesson03/mybatis.xml" ;

   InputStream inputStream = TestMybatis. class .getResourceAsStream(resource);

   SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);

   //打开会话

   SqlSession session = sqlSessionFactory.openSession();

   return session;

  }

  public static void main(String[] args) {

   SqlSession session = getSession();

   EmpMapper emp = session.getMapper(EmpMapper. class );

   Emp obj = emp.queryEmpByEmpNo( "8000" );

   System.out.println(obj);

  }

  @Test

  public void test(){

   SqlSession session = getSession();

   EmpMapper emp = session.getMapper(EmpMapper. class );

   List<Emp> result = emp.queryEmp();

   for (Emp emp2 : result) {

    System.out.println(emp2);

   }

  }

}

<? 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">

<!--

  接口映射

  namespace必需跟接口的全名一致

  -->

< mapper namespace = "cn.et.mybatis.lesson03.resultEntityXml.DeptMapper" >

  <!-- column是不区分大小写的，property是区分大小写的 -->

   < resultMap type = "cn.et.mybatis.lesson03.resultEntityXml.Dept" id = "myDept" >

     < result column = "deptno" property = "deptno1" />

     < result column = "dname" property = "dname1" />

     < result column = "loc" property = "loc1" />

   </ resultMap >

   < select id = "queryDept" resultMap = "myDept" >

  select * from dept where deptno=#{0}

   </ select > 

</ mapper >

package cn.et.mybatis.lesson03.resultEntityXml;

import java.io.InputStream;

import org.apache.ibatis.session.SqlSession;

import org.apache.ibatis.session.SqlSessionFactory;

import org.apache.ibatis.session.SqlSessionFactoryBuilder;

public class TestMybatis {

  public static SqlSession getSession(){

   String resource = "/cn/et/mybatis/lesson03/mybatis.xml" ;

   InputStream inputStream = TestMybatis. class .getResourceAsStream(resource);

   SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);

   //打开会话

   SqlSession session = sqlSessionFactory.openSession();

   return session;

  }

  public static void main(String[] args) {

   SqlSession session = getSession();

   DeptMapper dept = session.getMapper(DeptMapper. class );

   Dept result = dept.queryDept( "10" );

   System.out.println(result); 

  }

}

@Data

public class GenericKeyValueVo<K,V> {

     private K key;

     private V value;

}

< resultMap id = "StrKeyDoubleValueMap" type = "com.meinergy.mkting.commons.entity.wholesale.vo.GenericKeyValueVo" >

     < result column = "key" property = "key" javaType = "java.lang.String" />

     < result column = "value" property = "value" javaType = "java.lang.Double" />

</ resultMap >

convert(FORMAT(queryResult, decimal( 12 , 2 ))