后端实现增删改查功能

一、项目结构

二、详细代码

1、config

MybatisPlusConfig

package com.example.springbootmybatisplus.config;

import com.baomidou.mybatisplus.extension.plugins.MybatisPlusInterceptor;
import com.baomidou.mybatisplus.extension.plugins.inner.BlockAttackInnerInterceptor;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
//选中关键字alt+enter:导入相关依赖
/**
* 拦截 update 和 delete 语句   作用：于防止恶意的全表更新和删除操作
* */
@Configuration
public class MybatisPlusConfig {

    @Bean
    public MybatisPlusInterceptor mybatisPlusInterceptor() {
        MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();
        interceptor.addInnerInterceptor(new BlockAttackInnerInterceptor());
        return interceptor;
    }
}

2、entity

User

package com.example.springbootmybatisplus.entity;

import com.baomidou.mybatisplus.annotation.IdType;
import com.baomidou.mybatisplus.annotation.TableField;
import com.baomidou.mybatisplus.annotation.TableId;
import com.baomidou.mybatisplus.annotation.TableName;
import lombok.*;

import java.io.Serializable;

@Data
@AllArgsConstructor
@Getter
@Setter
@TableName("user")
public class User implements Serializable {
    private static final long serialVersionUID = 1L;
    @TableId(value = "id", type = IdType.AUTO)
    private Long id;
    private String username;
    private String password;
    private String email;
    private String city;
    @TableField(exist = false)
    private String sex;
    @TableField(exist = false)
    private Long userId;
    @TableField(exist = false)
    private UserInfo userInfo;

    public UserInfo getUserInfo() {
        return userInfo;
    }

    public void setUserInfo(UserInfo userInfo) {
        this.userInfo = userInfo;
    }

    public User() {
    }

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public String getCity() {
        return city;
    }

    public void setCity(String city) {
        this.city = city;
    }

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    public Long getUserId() {
        return userId;
    }

    public void setUserId(Long userId) {
        this.userId = userId;
    }
}

UserInfo

package com.example.springbootmybatisplus.entity;

import com.baomidou.mybatisplus.annotation.IdType;
import com.baomidou.mybatisplus.annotation.TableId;
import com.baomidou.mybatisplus.annotation.TableName;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.Getter;
import lombok.Setter;

import java.io.Serializable;

@Data
@AllArgsConstructor
@Getter
@Setter
@TableName("userInfo")
public class UserInfo implements Serializable {
    private static final long serialVersionUID = 1L;
    @TableId(value = "id", type = IdType.AUTO)
    private Long id;
    private String company;
    private String job;
    private String year;
    private Long UserId;

    public UserInfo() {
    }

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getCompany() {
        return company;
    }
    public void setCompany(String company) {
        this.company = company;
    }
    public String getJob() {
        return job;
    }
    public void setJob(String job) {
        this.job = job;
    }
    public String getYear() {
        return year;
    }
    public void setYear(String year) {
        this.year = year;
    }
    public Long getUserId() {
        return UserId;
    }
    public void setUserId(Long userId) {
        UserId = userId;
    }
}

3、对象封装vo

UserReqVO

package com.example.springbootmybatisplus.vo;

import lombok.Data;
import java.io.Serializable;

@Data
public class UserReqVO implements Serializable{
    private static final long serialVersionUID = 1L;
    private Long id;
    private String username;
    private String password;
    private String email;
    private String city;
    private String sex;

    private Long userId;
    private Integer pageNum;
    private Integer pageSize;
    private Integer total;

    public UserReqVO() {
    }

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public String getCity() {
        return city;
    }

    public void setCity(String city) {
        this.city = city;
    }

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }
    public Long getUserId() {
        return userId;
    }

    public void setUserId(Long userId) {
        this.userId = userId;
    }

    public Integer getPageNum() {
        return pageNum;
    }

    public void setPageNum(Integer pageNum) {
        this.pageNum = pageNum;
    }

    public Integer getPageSize() {
        return pageSize;
    }

    public void setPageSize(Integer pageSize) {
        this.pageSize = pageSize;
    }

    public Integer getTotal() {
        return total;
    }

    public void setTotal(Integer total) {
        this.total = total;
    }
}

4、controller

TestController

package com.example.springbootmybatisplus.controller;


import com.example.springbootmybatisplus.entity.User;
import com.example.springbootmybatisplus.mapper.UserMapper;
import com.example.springbootmybatisplus.service.IUserService;
import com.example.springbootmybatisplus.vo.UserReqVO;
import com.github.pagehelper.PageInfo;
import jakarta.annotation.Resource;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

import java.util.List;

@RestController
@RequestMapping("/user")
public class TestController {

    @Autowired
    private UserMapper userMapper;
    @Resource
    private IUserService userservice;

    //查询列表
    @GetMapping("/getUserList")
    public List<User> list() {
//        return userMapper.selectList( null);
        return userservice.selectUserList();
    }
    //分页查询
    @GetMapping("/getUserListPage")
    public PageInfo<User> listPage() {
        return userservice.selectUserListPage(1, 2);
    }
    //带条件的分页查询
    @GetMapping("/getserchListPage")
    public PageInfo<User> serchListPage(
            @RequestParam(defaultValue = "1") int currentPage,
            @RequestParam(defaultValue = "2") int pageSize,
            @RequestParam(required = false) Long id,
            @RequestParam(required = false) String username,
            @RequestParam(required = false) String password,
            @RequestParam(required = false) String email,
            @RequestParam(required = false) String city
    ) {
        return userservice.selectListPage(currentPage, pageSize, id, username, password, email, city);
    }

    /**
     *
     *封装
     * @return
     */
    @GetMapping("/selectUserObjListPage")
    public PageInfo<User> selectUserObjListPage(UserReqVO user) {
        return userservice.selectUserObjListPage(user);
    }
    /**
     *
     *新增和修改功能
     * @return
     */
    @PostMapping("/addAndeditUser")
    public int addAndeditUser(@RequestBody UserReqVO user) {
        return userservice.saveOrUpdate(user);
    }
    /**
     *
     *删除功能
     * @return
     */
    @GetMapping("/deleteUser")
    public int deleteUser(@RequestParam Long id) {
        return userservice.deleteById(id);
    }
    /**
     *
     *根据id查询详情功能
     * @return
     */
    @GetMapping("/getUserById")
    public User getUserById(@RequestParam Long id) {
        return userservice.selectById(id);
    }

}

5、mapper

UserMapper

package com.example.springbootmybatisplus.mapper;

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.example.springbootmybatisplus.entity.User;
import org.apache.ibatis.annotations.Mapper;

/**
 * 继承User
 * **/
@Mapper
public interface UserMapper extends BaseMapper<User> {
    // 不需要添加其他注解或特殊配置

}

UserInfoMapper

package com.example.springbootmybatisplus.mapper;

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.example.springbootmybatisplus.entity.UserInfo;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Param;
import org.apache.ibatis.annotations.Select;


@Mapper
public interface UserInfoMapper extends BaseMapper<UserInfo> {
    @Select("SELECT id,company,job,year,user_id FROM userInfo WHERE user_id = #{userId}")
    UserInfo selectByUserId(@Param("userId") Long userId);
    // 不需要添加其他注解或特殊配置
}

6、service

IUserService

package com.example.springbootmybatisplus.service;

import com.example.springbootmybatisplus.entity.User;
import com.example.springbootmybatisplus.vo.UserReqVO;
import com.github.pagehelper.PageInfo;

import java.util.List;

public interface IUserService {
    List<User> selectUserList();
    //分页查询
    PageInfo<User> selectUserListPage(int pageNum, int pageSize);
    /**
     * 根据条件分页查询用户
     * @param currentPage 当前页码
     * @param pageSize 每页大小
     * @param id 用户ID
     * @param username 用户名
     * @param password 密码
     * @param email 邮箱
     * @param city 城市
     * @return 分页结果
     */
    PageInfo<User> selectListPage(int currentPage, int pageSize, Long id, String username, String password, String email, String city);

    PageInfo<User> selectUserObjListPage(UserReqVO user);
    int saveOrUpdate(UserReqVO user);
    int deleteById(Long id);
    User selectById(Long id);

}

impl->UserServiceImpl

package com.example.springbootmybatisplus.service.impl;

import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.example.springbootmybatisplus.entity.User;
import com.example.springbootmybatisplus.entity.UserInfo;
import com.example.springbootmybatisplus.mapper.UserInfoMapper;
import com.example.springbootmybatisplus.mapper.UserMapper;
import com.example.springbootmybatisplus.service.IUserService;
import com.example.springbootmybatisplus.vo.UserReqVO;
import com.github.pagehelper.PageHelper;
import com.github.pagehelper.PageInfo;
import jakarta.annotation.Resource;
import org.springframework.stereotype.Service;
import org.springframework.util.ObjectUtils;
import org.springframework.util.StringUtils;

import java.util.List;

@Service
public class UserServiceImpl implements IUserService {

    @Resource
    private UserMapper userMapper;
    @Resource
    private UserInfoMapper userInfoMapper;

    @Override
    public List<User> selectUserList() {
        return userMapper.selectList( null);
    }
    @Override
    public PageInfo<User> selectUserListPage(int pageNum, int pageSize) {
        //这是mybatis提供的分页插件
        PageHelper.startPage(pageNum, pageSize);
        List<User> userList = userMapper.selectList(null);//这个queryWrapper就是查询的sql条件
        return new PageInfo<>(userList);//返回的这个PageInfo对象，封装了分页的详细信息  数据集合  页码  页数  总数等都有
    }
    //根据条件分页查询
    @Override
    public PageInfo<User> selectListPage(int currentPage, int pageSize,
                                      Long id, String username, String password,
                                      String email, String city){
        // 构造分页对象
        PageHelper.startPage(currentPage, pageSize);

        // 构造查询条件
        LambdaQueryWrapper<User> queryWrapper = new LambdaQueryWrapper<>();

        // 添加各字段查询条件
        if (id != null) {
            queryWrapper.eq(User::getId, id);
        }
        if (StringUtils.hasText(username)) {
            queryWrapper.like(User::getUsername, username);
        }
        if (StringUtils.hasText(password)) {
            queryWrapper.eq(User::getPassword, password);
        }
        if (StringUtils.hasText(email)) {
            queryWrapper.like(User::getEmail, email);
        }
        if (StringUtils.hasText(city)) {
            queryWrapper.like(User::getCity, city);
        }
        List<User> selsetList = userMapper.selectList(queryWrapper);
        // 执行分页查询
        return new PageInfo<>(selsetList);
    }

    @Override
    public PageInfo<User> selectUserObjListPage(UserReqVO user) {
        if(ObjectUtils.isEmpty(user)){
            throw new RuntimeException("参数错误");
        }
        // 构造分页对象
        PageHelper.startPage(user.getPageNum(), user.getPageSize());

        // 构造查询条件
        LambdaQueryWrapper<User> queryWrapper = new LambdaQueryWrapper<>();

        // 添加各字段查询条件
        if (user.getId() != null) {
            queryWrapper.eq(User::getId, user.getId());
        }
        if (StringUtils.hasText(user.getUsername())) {
            queryWrapper.like(User::getUsername, user.getUsername());
        }
        if (StringUtils.hasText(user.getPassword())) {
            queryWrapper.eq(User::getPassword, user.getPassword());
        }
        if (StringUtils.hasText(user.getEmail())) {
            queryWrapper.like(User::getEmail, user.getEmail());
        }
        if (StringUtils.hasText(user.getCity())) {
            queryWrapper.like(User::getCity, user.getCity());
        }
        List<User> selsetList = userMapper.selectList(queryWrapper);
        // 执行分页查询
        return new PageInfo<>(selsetList);
    }
    //新增或修改
    @Override
    public int saveOrUpdate(UserReqVO user) {
        if(ObjectUtils.isEmpty(user)){
            throw new RuntimeException("参数错误");
        }
        User user1 = new User();
        user1.setId(user.getId());
        user1.setUsername(user.getUsername());
        user1.setPassword(user.getPassword());
        user1.setEmail(user.getEmail());
        user1.setCity(user.getCity());
        user1.setSex(user.getSex());
        user1.setUserId(user.getUserId());
        if(user.getId() == null){

            return userMapper.insert(user1);
        }else{
            return userMapper.updateById(user1);
        }
    }

    @Override
    public int deleteById(Long id) {
        if(id != null){
            return userMapper.deleteById(id);
        }else {
            throw new RuntimeException("请传入id");
        }
    }

    @Override
    public User selectById(Long id) {
      if (id != null){
          //查询主表信息
          User user = userMapper.selectById(id);
          //查询附表userid对应的信息
          UserInfo userInfo = userInfoMapper.selectByUserId(id);

          //将明细表的数据封装进主表
            user.setUserInfo(userInfo);
          return user;
      }else{
          throw new RuntimeException("请传入id");
      }
    }

}

7、启动类SpringBootMybatisPlusApplication

package com.example.springbootmybatisplus;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class SpringBootMybatisPlusApplication {

    public static void main(String[] args) {

        SpringApplication.run(SpringBootMybatisPlusApplication.class, args);
    }

}

8、数据库连接

application.properties

spring.application.name=SpringBoot-mybatis-plus
spring.datasource.url=jdbc:mysql://localhost:3306/wj
spring.datasource.username=root
spring.datasource.password=123456
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver

# MyBatis-Plus??
mybatis-plus.mapper-locations=classpath*:mapper/**/*.xml
mybatis-plus.type-aliases-package=org.example.demojavatestinfo.entity
mybatis-plus.configuration.map-underscore-to-camel-case=true

application.yml

spring:
  datasource:
    driver-class-name: com.mysql.jdbc.Driver
    url: jdbc:mysql://localhost:3306/wj
    username: root
    password: 123456
    hikari:
      minimum-idle: 5
      maximum-pool-size: 20
      auto-commit: true
      idle-timeout: 30000
      pool-name: HikariCP
      max-lifetime: 1800000
      connection-timeout: 30000

三、相关注解解释及作用

类级别注解

1. @RestController

@RestController

• 含义 : 组合注解，相当于@Controller + @ResponseBody
• 作用: 表明该类是一个RESTful风格的控制器，所有方法的返回值都会自动序列化为JSON格式
• 用法: 用于定义REST API的控制器类

2. @RequestMapping("/user")

@RequestMapping("/user")

• 含义: 请求映射注解
• 作用 : 定义该类中所有方法的公共URL前缀为/user
• 用法 : 类级别的路径映射，所有方法URL都会以/user开头

依赖注入注解

3. @Autowired

@Autowired
private UserMapper userMapper;

• 含义: Spring的自动注入注解
• 作用 : 根据类型自动注入UserMapper实例
• 用法: 用于字段、构造函数或setter方法，按类型进行依赖注入

4. @Resource

@Resource
private IUserService userservice;

• 含义: JSR-250标准的依赖注入注解
• 作用: 默认按名称进行依赖注入，如果未指定名称则按类型注入
• 与@Autowired区别 : @Resource是Java标准注解，@Autowired是Spring特有

方法级别注解（HTTP方法映射）

5. @GetMapping

@GetMapping("/getUserList")

• 含义: 处理HTTP GET请求的快捷注解
• 作用: 映射GET请求到特定方法
• 等价于 : @RequestMapping(method = RequestMethod.GET)

6. @PostMapping

@PostMapping("/addAndeditUser")

• 含义: 处理HTTP POST请求的快捷注解
• 作用: 映射POST请求到特定方法
• 用法: 通常用于创建或更新操作

参数绑定注解

7. @RequestParam

@RequestParam(defaultValue = "1") int currentPage
@RequestParam(required = false) Long id

• 含义: 将请求参数绑定到方法参数

• 属性:

  • defaultValue: 设置参数默认值
  • required: 参数是否必须（默认true）

• 用法: 用于获取URL查询参数或表单参数

8. @RequestBody

@RequestBody UserReqVO user

• 含义: 将请求体内容绑定到方法参数
• 作用: 用于接收JSON格式的请求数据
• 用法: 通常用于POST/PUT请求，接收复杂对象

9.@Override

@Override
public void someMethod() {
    // 方法实现
}

• 含义: 表明该方法重写了父类或接口中的方法
• 作用: 编译器检查注解，确保重写正确性
• 级别: 源码级别注解（编译后不会保留）