1.1 步骤
(1) 去掉 之前编写的Dao 接口实现类
(2) getMapper 获取代理对象
只需调用 SqlSession 的 getMapper()方法,即可获取指定接口的实现类对象。该方法的参数为指定 Dao接口类的 class 值。
不使用工具类:
SqlSession session = factory.openSession();
StudentDao dao = session.getMapper(StudentDao.class);
使用工具类:
SqlSession sqlSession = MybatisUtils.getSqlSession();
// 这句代码可以自动创建dao接口的实现类对象
StudentDao dao = sqlSession.getMapper(StudentDao.class);
(3) 使用 Dao 代理对象方法执行 sql 语句
@Test
public void testSelectStudents() {
/**
* 使用mybatis的动态代理机制,使用SqlSession.getMapper(dao接口)
* getMapper能够获取dao接口对应的实现类对象。
*/
SqlSession sqlSession = MybatisUtils.getSqlSession();
StudentDao dao = sqlSession.getMapper(StudentDao.class); // 这句代码可以自动创建dao接口的实现类对象
//调用dao的方法,执行数据库的操作
List<Student> students = dao.selectStudents();
for (Student student : students) {
System.out.println("学生=" + student);
}
}
@Test
public void testInsertStudents() {
SqlSession sqlSession = MybatisUtils.getSqlSession();
StudentDao dao = sqlSession.getMapper(StudentDao.class);
Student student = new Student();
student.setId(1004);
student.setName("亚瑟");
student.setEmail("[email protected]");
student.setAge(35);
int nums = dao.insertStudent(student);
sqlSession.commit();
System.out.println("添加对象的数量:" + nums);
}
@Test
public void testUpdateStudents() {
SqlSession sqlSession = MybatisUtils.getSqlSession();
StudentDao dao = sqlSession.getMapper(StudentDao.class);
Student student = new Student();
student.setId(1002);
student.setAge(222);
int nums = dao.updateStudent(student);
sqlSession.commit();
System.out.println("更新对象的数量:" + nums);
}
@Test
public void testDeleteStudents() {
SqlSession sqlSession = MybatisUtils.getSqlSession();
StudentDao dao = sqlSession.getMapper(StudentDao.class);
int nums = dao.deleteStudent(1003);
sqlSession.commit();
System.out.println("删除对象的数量:" + nums);
}
在上一篇博文三、MyBatis 使用传统 Dao 开发方式的基础上,只做了以下更改:
- 删除dao的实现类StudentDaoImpl
- 修改TestMybatis的代码:
所以缺少的代码请参考三、MyBatis 使用传统 Dao 开发方式
package com.zep;
import com.zep.dao.StudentDao;
import com.zep.domain.Student;
import com.zep.utils.MybatisUtils;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;
import java.util.List;
public class TestMybatis {
@Test
public void testSelectStudents() {
/**
* 使用mybatis的动态代理机制,使用SqlSession.getMapper(dao接口)
* getMapper能够获取dao接口对应的实现类对象。
*/
SqlSession sqlSession = MybatisUtils.getSqlSession();
StudentDao dao = sqlSession.getMapper(StudentDao.class); // 这句代码可以自动创建dao接口的实现类对象
//调用dao的方法,执行数据库的操作
List<Student> students = dao.selectStudents();
for (Student student : students) {
System.out.println("学生=" + student);
}
}
@Test
public void testInsertStudents() {
SqlSession sqlSession = MybatisUtils.getSqlSession();
StudentDao dao = sqlSession.getMapper(StudentDao.class);
Student student = new Student();
student.setId(1004);
student.setName("亚瑟");
student.setEmail("[email protected]");
student.setAge(35);
int nums = dao.insertStudent(student);
sqlSession.commit();
System.out.println("添加对象的数量:" + nums);
}
@Test
public void testUpdateStudents() {
SqlSession sqlSession = MybatisUtils.getSqlSession();
StudentDao dao = sqlSession.getMapper(StudentDao.class);
Student student = new Student();
student.setId(1002);
student.setAge(222);
int nums = dao.updateStudent(student);
sqlSession.commit();
System.out.println("更新对象的数量:" + nums);
}
@Test
public void testDeleteStudents() {
SqlSession sqlSession = MybatisUtils.getSqlSession();
StudentDao dao = sqlSession.getMapper(StudentDao.class);
int nums = dao.deleteStudent(1003);
sqlSession.commit();
System.out.println("删除对象的数量:" + nums);
}
}