MyBatis-结果集封装map和pojo

使用map存储结果集

使用规范

• 原则上,所有的结果集都可以存储到map
• 但使用map存储,会大大降低阅读性
• mapper文件中使用map存储结果的参考

  <select id="xxx" resultType="map">
  	...                           
  select>                           
  

测试步骤参考

• 全局配置文件和实体类省略
• mapper文件配置

                      
  <select id="get_map" resultType="map">  
  	select * from emp                   
  select>                               
  

• mapper接口省略
• 主要测试类部分截取

  Test_resultType dao = session.getMapper(Test_resultType.class);
  // 将结果对象依次封装到 map 实例中
  // 以 key-value 的形式
  // key 表示属性; value 表示属性值
  List<Map<?, ?>> list = dao.get_map();
  for (Map<?, ?> map : list)
  {
  	log.info(map);
  }
  

• 校验输出部分截取

  DEBUG 2019-01-13 00:18:24,865 org.apache.ibatis.logging.jdbc.BaseJdbcLogger : <==      Total: 15
   INFO 2019-01-13 00:18:24,866 siye.ibatis.test.Test_mapper_conf : {sex=1, name=xiaoli, id=1, age=23}
   INFO 2019-01-13 00:18:24,866 siye.ibatis.test.Test_mapper_conf : {sex=1, name=xiaohong, id=2, age=28}
   INFO 2019-01-13 00:18:24,866 siye.ibatis.test.Test_mapper_conf : {sex=1, name=xiaofang, id=3, age=28}
   INFO 2019-01-13 00:18:24,866 siye.ibatis.test.Test_mapper_conf : {sex=1, name=xiaofang, id=4, age=28}
   INFO 2019-01-13 00:18:24,867 siye.ibatis.test.Test_mapper_conf : {sex=1, name=xiaofang, id=5, age=28}
   INFO 2019-01-13 00:18:24,867 siye.ibatis.test.Test_mapper_conf : {sex=1, name=xiaofang, id=6, age=28}
   INFO 2019-01-13 00:18:24,867 siye.ibatis.test.Test_mapper_conf : {sex=0, name=xiaoHua, id=7, age=90}
   INFO 2019-01-13 00:18:24,867 siye.ibatis.test.Test_mapper_conf : {sex=0, name=xiaoHua, id=8, age=87}
   INFO 2019-01-13 00:18:24,867 siye.ibatis.test.Test_mapper_conf : {sex=0, name=xiaoLi, id=9, age=66}
   INFO 2019-01-13 00:18:24,867 siye.ibatis.test.Test_mapper_conf : {sex=0, name=Rose, id=10, age=23}
   INFO 2019-01-13 00:18:24,867 siye.ibatis.test.Test_mapper_conf : {name=xiao_zhu, id=11}
   INFO 2019-01-13 00:18:24,868 siye.ibatis.test.Test_mapper_conf : {name=xiao_zhu, id=12}
   INFO 2019-01-13 00:18:24,868 siye.ibatis.test.Test_mapper_conf : {name=xiao_zhu, id=13}
   INFO 2019-01-13 00:18:24,868 siye.ibatis.test.Test_mapper_conf : {sex=0, name=xiaoHua, id=14, age=34}
   INFO 2019-01-13 00:18:24,868 siye.ibatis.test.Test_mapper_conf : {sex=0, name=xiaoHua, id=15, age=83}
  

使用POJO存储结果集

使用规范

• 只需指定合法的POJO类对象的正确包路径即可
• 可以是完全限定名,也可以是别名
• 强大的可读性,和对执行结果的便捷操作,较为推荐的方式
• mapper文件中使用POJO存储结果集的参考

  <select id="xxx" resultType="object_qualifier_name"> 
  	...                                              
  select>                                            
  

测试步骤参考

• 全局配置文件和实体类省略
• mapper文件的配置

                                        
  <select id="get_pojo" resultType="siye.ibatis.entity.Emp"> 
  	select * from emp                                      
  select>                                                  
  

• mapper接口省略
• 主要测试类部分截取

  Test_resultType dao = session.getMapper(Test_resultType.class);
  // 依据 POJO 映射封装,依次填入到 list 实例中
  List<Emp> list = dao.get_pojo();
  for (Emp emp : list)
  {
  	log.info(emp);
  }
  

• 校验输出部分截取

  DEBUG 2019-01-13 00:25:10,463 org.apache.ibatis.logging.jdbc.BaseJdbcLogger : <==      Total: 15
   INFO 2019-01-13 00:25:10,463 siye.ibatis.test.Test_mapper_conf : siye.ibatis.entity.Emp@150c158
   INFO 2019-01-13 00:25:10,464 siye.ibatis.test.Test_mapper_conf : siye.ibatis.entity.Emp@124411f
   INFO 2019-01-13 00:25:10,464 siye.ibatis.test.Test_mapper_conf : siye.ibatis.entity.Emp@1e7803
   INFO 2019-01-13 00:25:10,464 siye.ibatis.test.Test_mapper_conf : siye.ibatis.entity.Emp@dba097
   INFO 2019-01-13 00:25:10,464 siye.ibatis.test.Test_mapper_conf : siye.ibatis.entity.Emp@186f9d5
   INFO 2019-01-13 00:25:10,464 siye.ibatis.test.Test_mapper_conf : siye.ibatis.entity.Emp@4d6e83
   INFO 2019-01-13 00:25:10,464 siye.ibatis.test.Test_mapper_conf : siye.ibatis.entity.Emp@1a0cee9
   INFO 2019-01-13 00:25:10,464 siye.ibatis.test.Test_mapper_conf : siye.ibatis.entity.Emp@b21112
   INFO 2019-01-13 00:25:10,465 siye.ibatis.test.Test_mapper_conf : siye.ibatis.entity.Emp@da0940
   INFO 2019-01-13 00:25:10,465 siye.ibatis.test.Test_mapper_conf : siye.ibatis.entity.Emp@178436e
   INFO 2019-01-13 00:25:10,465 siye.ibatis.test.Test_mapper_conf : siye.ibatis.entity.Emp@6a04ae
   INFO 2019-01-13 00:25:10,465 siye.ibatis.test.Test_mapper_conf : siye.ibatis.entity.Emp@ceb130
   INFO 2019-01-13 00:25:10,465 siye.ibatis.test.Test_mapper_conf : siye.ibatis.entity.Emp@a035a0
   INFO 2019-01-13 00:25:10,465 siye.ibatis.test.Test_mapper_conf : siye.ibatis.entity.Emp@1b467e9
   INFO 2019-01-13 00:25:10,465 siye.ibatis.test.Test_mapper_conf : siye.ibatis.entity.Emp@1db50c5