文章目录

• 业务层开发
• • 编写service层
  • • 接口
    • 实现类
    • 测试类
    • • 测试成功
    • 多个测试方法
    • • 测试成功
  • 小结
• 业务层快速开发（基于MyBatis-Plus）
• • 编写service层
  • • 实现类
    • 测试类
  • 如果mybatis-plus给的方法不够用
  • • 模拟编写接口
    • 模拟编写IUserServiceImpl
    • 注意
  • 小结

业务层开发

编写service层

接口

package com.taotao.service;

import com.baomidou.mybatisplus.core.metadata.IPage;
import com.taotao.domain.User;

import java.util.List;

/**
 * create by 刘鸿涛
 * 2022/5/4 19:32
 */
@SuppressWarnings({"all"})
public interface UserService {
    Boolean save(User user);
    Boolean updata(User user);
    Boolean delete(Integer id);
    User getById(Integer id);
    List<User> getAll();
    IPage<User> getPage(int currentPage,int pageSize);
}

实现类

package com.taotao.service.impl;

import com.taotao.dao.UserMapper;
import com.taotao.domain.User;
import com.taotao.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.nio.file.attribute.UserDefinedFileAttributeView;
import java.util.List;

/**
 * create by 刘鸿涛
 * 2022/5/4 19:36
 */
@SuppressWarnings({"all"})
//业务层对应的bean
@Service
public class UserServiceImpl implements UserService {
    @Autowired
    private UserMapper userMapper;

    @Override
    public Boolean save(User user) {
        return userMapper.insert(user) > 0; //影响行大于0时进行操作
    }

    @Override
    public Boolean updata(User user) {
        return userMapper.updateById(user) > 0;
    }

    @Override
    public Boolean delete(Integer id) {
        return userMapper.deleteById(id) > 0;
    }

    @Override
    public User getById(Integer id) {
        return userMapper.selectById(id);
    }

    @Override
    public List<User> getAll() {
        return userMapper.selectList(null);
    }
}

测试类

package com.taotao.service;

import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;

/**
 * create by 刘鸿涛
 * 2022/5/4 19:47
 */
@SuppressWarnings({"all"})
@SpringBootTest
public class UserServiceTestCase {

    @Autowired
    private UserService userService;

    @Test
    void testGetById(){
        System.out.println(userService.getById(4));
    }
}

测试成功

多个测试方法

package com.taotao.service;

import com.baomidou.mybatisplus.core.metadata.IPage;
import com.taotao.domain.User;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;

/**
 * create by 刘鸿涛
 * 2022/5/4 19:47
 */
@SuppressWarnings({"all"})
@SpringBootTest
public class UserServiceTestCase {

    @Autowired
    private UserService userService;

    @Test
    void testGetById(){
        System.out.println(userService.getById(4));
    }

    //添加
    @Test
    void testSave(){
        User user = new User();
        user.setUsername("taotao");
        user.setAddr("上海");
        user.setPassword(456);
        user.setGender("女");
        userService.save(user);
    }

    @Test
    void testUpdata(){
        User user = new User();
        user.setId(3);
        user.setUsername("刘鸿涛");
        user.setAddr("上海");
        user.setPassword(456);
        user.setGender("男");
        userService.updata(user);
    }

    @Test
    void testDelete(){
        userService.delete(4);
    }

    //查询所有
    @Test
    void testGetAll(){
        userService.getAll();
    }

    @Test
    void testGetPage(){
        //两个参数分别代表“第几页”，每页显示多少条数据
        IPage<User> page = userService.getPage(2, 2);
//        System.out.println(page.getCurrent());
//        System.out.println(page.getRecords());
//        System.out.println(page.getSize());
//        System.out.println(page.getTotal());
    }
}

测试成功

小结

业务层快速开发（基于MyBatis-Plus）

编写service层

package com.taotao.service;

import com.baomidou.mybatisplus.extension.service.IService;
import com.taotao.domain.User;

/**
 * create by 刘鸿涛
 * 2022/5/4 21:18
 */
@SuppressWarnings({"all"})
public interface IBookService extends IService<User> {
}

实现类

package com.taotao.service.impl;

import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.taotao.dao.UserMapper;
import com.taotao.domain.User;
import com.taotao.service.IUserService;
import org.springframework.stereotype.Service;

/**
 * create by 刘鸿涛
 * 2022/5/4 21:31
 */
@SuppressWarnings({"all"})
@Service
public class IUserServiceImpl extends ServiceImpl<UserMapper, User> implements IUserService {

}

测试类

package com.taotao.service;

import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.taotao.domain.User;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;

/**
 * create by 刘鸿涛
 * 2022/5/4 19:47
 */
@SuppressWarnings({"all"})
@SpringBootTest
public class IUserServiceTestcase {

    @Autowired
    private IUserService userService;

    @Test
    void testGetById(){
        System.out.println(userService.getById(4));
    }

    //添加
    @Test
    void testSave(){
        User user = new User();
        user.setUsername("taotao");
        user.setAddr("上海");
        user.setPassword(456);
        user.setGender("女");
        userService.save(user);
    }

    @Test
    void testUpdata(){
        User user = new User();
        user.setId(3);
        user.setUsername("刘鸿涛");
        user.setAddr("上海");
        user.setPassword(456);
        user.setGender("男");
        userService.updateById(user);
    }

    @Test
    void testDelete(){
        userService.removeById(4);
    }

    //查询所有
    @Test
    void testGetAll(){
        userService.list();
    }

    @Test
    void testGetPage(){
        //两个参数分别代表“第几页”，每页显示多少条数据
        Page<User> page = new Page<User>(2,2);
        userService.page(page);
    }
}

如果mybatis-plus给的方法不够用

模拟编写接口

package com.taotao.service;

import com.baomidou.mybatisplus.extension.service.IService;
import com.taotao.domain.User;

/**
 * create by 刘鸿涛
 * 2022/5/4 21:18
 */
@SuppressWarnings({"all"})
public interface IUserService extends IService<User> {
    boolean saveUser(User user);
    
    boolean modify(User user);
    
    boolean delete(Integer id);
}

模拟编写IUserServiceImpl

package com.taotao.service.impl;

import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.taotao.dao.UserMapper;
import com.taotao.domain.User;
import com.taotao.service.IUserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

/**
 * create by 刘鸿涛
 * 2022/5/4 21:31
 */
@SuppressWarnings({"all"})
@Service
public class IUserServiceImpl extends ServiceImpl<UserMapper, User> implements IUserService {

    @Autowired
    private UserMapper userMapper;

    @Override
    public boolean saveUser(User user) {
        return userMapper.insert(user) > 0;
    }

    @Override
    public boolean modify(User user) {
        return userMapper.updateById(user) > 0;
    }

    @Override
    public boolean delete(Integer id) {
        return userMapper.deleteById(id) > 0;
    }
}

注意

• 我们重载的时候没有必要再重写一遍MP有的方法，在方法里再调用一次就行了

小结