Mybatis实现增、删、改操作时返回主键

需求:查询出刚刚插入(删除/修改)的记录的详细信息

　　1、xxxMapper接口

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public interface EmployeeMapper {     // 添加操作     public int insertEmployee(Employee employee);       // 根据ID查询出一条记录     public Employee queryEmployeeByEmployeeId(Integer employeeId); }

　　2、xxxMapper.xml

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<mapper namespace="com.mybatis.dao.EmployeeMapper">     // 插入一条记录     // useGeneratedKeys:默认值是true,但是还是建议写上     // keyProperty:将刚刚插入的记录的主键使用传入的Employee对象中的employeeId属性接收     <insert id="insertEmployee" useGeneratedKeys="true" keyProperty="employeeId">         INSERT INTO employee VALUES (null,#{employeeName},#{employeePassword},#{employeeAge},#{departmentId})     </insert>     // 根据employeeId查询Employee对象     <select id="queryEmployeeByEmployeeId" resultType="com.mybatis.entity.Employee">         SELECT EMPLOYEE_ID,EMPLOYEE_NAME,EMPLOYEE_PASSWORD,EMPLOYEE_AGE,DEPARTMENT_ID FROM employee         WHERE EMPLOYEE_ID=#{employeeId}     </select> </mapper>

　　3、测试类

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@Test     public void test01() throws IOException {         SqlSession session = TestMybatis.openSession();         EmployeeMapper mapper = session.getMapper(EmployeeMapper.class);         Employee employee = new Employee();         employee.setEmployeeName("田七");         employee.setEmployeeAge("27");         employee.setEmployeePassword("4456");         employee.setDepartmentId(4);         // 这里返回的是影响的行数         int i = mapper.insertEmployee(employee);         // 根据插入的id,查询出刚刚插入的记录,因为我们将插入的主键封装进了Employee对象的employeeId属性中         Employee e = mapper.queryEmployeeByEmployeeId(employee.getEmployeeId());         System.out.println(e);     }

　　4、测试结果

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1	Employee{employeeId=9, employeeName='田七', employeePassword='4456', employeeAge='27', departmentId=4}