二、注解实现

二、注解实现

前四步参考【一、Mybatis项目搭建】

5) 定义 sql 映射的接口

package com.mybatis.dao;

 

import java.util.List;

import org.apache.ibatis.annotations.Delete;

import org.apache.ibatis.annotations.Insert;

import org.apache.ibatis.annotations.Select;

import org.apache.ibatis.annotations.Update;

import com.mybatis.entity.User;

 

public interface UserDao {

   //根据ID查询用户

   @Select("select * from users where id=#{id}")

   public User getUserById(int id);

   //查询所有用户

   @Select("select * from users")

   public List<User> getAllUsers();

   //添加用户

   @Insert("insert into users (id,name,age) values(id_seq.nextval,#{name},#{age})")

   public int addUser(User user);

   //删除用户

   @Delete("delete from users where id=#{id}")

   public int deleteUserById(int id);

   //更新用户

   @Update("update users set name=#{name},age=#{age} whereid=#{id}")

   public int updateUser(User user);

}

6) 在 conf.xml 中注册这个映射接口

<mapper class="com.mybatis.dao.UserDao" />

7) 测试。（DbUtil参考【一、Mybatis项目搭建】）

package com.mybatis.test;

 

import static org.junit.Assert.*;

import org.apache.ibatis.session.SqlSession;

import org.junit.Test;

import com.mybatis.dao.UserDao;

import com.mybatis.entity.User;

import com.mybatis.util.DbUtil;

public class UserTest {

 

   SqlSessionsession = DbUtil.getSession();

   UserDaouserDao = session.getMapper(UserDao.class);

   Useruser = new User();

  

   @Test

   public void testSelectUser() {

      try {

        System.out.println(userDao.getUserById(2));

      }catch (Exception e) {

        e.printStackTrace();

        fail("Not yet implemented");

      }

   }

  

   @Test

   public void testSelectUsers() {

      try {

        System.out.println(userDao.getAllUsers());

      }catch (Exception e) {

        e.printStackTrace();

        fail("Not yet implemented");

      }

   }

  

   @Test

   public void addUsers() {

      int insertok = 0;

      try {

        user.setName("wangwu");

        user.setAge(1);

        insertok = userDao.addUser(user);

        System.out.println(insertok);

        if(insertok > 0){

           session.commit();

           System.out.println("插入成功");

        }else {

           System.out.println("插入失败");

        }

      }catch (Exception e) {

        e.printStackTrace();

        fail("Not yet implemented");

      }

   }

 

   @Test

   public void deleteUsers() {

      int deleteok = 0;

      try {

        user.setId(47);

        deleteok = userDao.deleteUserById(user.getId());

        System.out.println(deleteok);

        if(deleteok > 0){

           session.commit();

           System.out.println("删除成功");

        }else {

           System.out.println("删除失败");

        }

      }catch (Exception e) {

        e.printStackTrace();

        fail("Not yet implemented");

      }

   }

 

   @Test

   public void updateUsers() {

      int updateok = 0;

      try {

        user.setId(41);

        user.setName("cat");

        user.setAge(2);

        updateok = userDao.updateUser(user);

        System.out.println(updateok);

        if(updateok > 0){

           session.commit();

           System.out.println("更新成功");

        }else {

           System.out.println("更新失败");

        }

      }catch (Exception e) {

        e.printStackTrace();

        fail("Not yet implemented");

      }

   }

}