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 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 result = emp.queryEmp(); for (Emp emp2 : result) { System.out.println(emp2); } } }

     select * from dept where deptno=#{0} 

 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 { private K key; private V value; } 

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