Spring Boot 3.0 + MyBatis-Plus全家桶实战详细代码

<properties>
    <java.version>17</java.version>
    <spring-boot.version>3.0.8</spring-boot.version> <!-- 任选 Spring Boot 3.0.x -->
    <mybatis-plus.version>3.5.12</mybatis-plus.version> <!-- 官方 Maven 中央库示例版本 -->
</properties>

<dependencies>
    <!-- Spring Boot Starter Web -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>

    <!-- Spring Boot Starter JDBC / DataSource -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-jdbc</artifactId>
    </dependency>

    <!-- MyBatis-Plus Spring Boot 3 starter -->
    <dependency>
        <groupId>com.baomidou</groupId>
        <artifactId>mybatis-plus-spring-boot3-starter</artifactId>
        <version>${mybatis-plus.version}</version>
    </dependency>

    <!-- 数据库驱动（示例用 MySQL） -->
    <dependency>
        <groupId>com.mysql</groupId>
        <artifactId>mysql-connector-j</artifactId>
        <scope>runtime</scope>
    </dependency>

    <!-- 可选：Lombok (简化实体) -->
    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <optional>true</optional>
    </dependency>

    <!-- 测试 -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
    </dependency>
</dependencies>

spring:
  datasource:
    url: jdbc:mysql://localhost:3306/demo?useUnicode=true&characterEncoding=utf8&serverTimezone=UTC
    username: root
    password: root
    driver-class-name: com.mysql.cj.jdbc.Driver

mybatis-plus:
  configuration:
    # 驼峰映射：数据库 user_name -> Java userName
    map-underscore-to-camel-case: true
  global-config:
    db-config:
      logic-delete-field: deleted     # 逻辑删除字段名（可选）
      logic-delete-value: 1
      logic-not-delete-value: 0
  # mapper xml 路径（若使用 xml）
  mapper-locations: classpath:/mapper/**/*.xml
  type-aliases-package: com.example.demo.entity

CREATE TABLE user (
  id BIGINT AUTO_INCREMENT PRIMARY KEY,
  username VARCHAR(100),
  email VARCHAR(200),
  age INT,
  version INT DEFAULT 0,
  deleted TINYINT DEFAULT 0,
  created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
  updated_at DATETIME DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
);

package com.example.demo.entity;

import com.baomidou.mybatisplus.annotation.*;
import lombok.Data;
import java.time.LocalDateTime;

@Data
@TableName("user")
public class User {
    @TableId(type = IdType.AUTO)
    private Long id;

    private String username;
    private String email;
    private Integer age;

    @Version
    private Integer version; // 乐观锁字段，@Version 标注

    @TableLogic
    private Integer deleted; // 逻辑删除，0 未删除，1 已删除

    @TableField(fill = FieldFill.INSERT)
    private LocalDateTime createdAt;

    @TableField(fill = FieldFill.INSERT_UPDATE)
    private LocalDateTime updatedAt;
}

package com.example.demo.mapper;

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

@Mapper
public interface UserMapper extends BaseMapper<User> {
    // BaseMapper 已经包含常见 CRUD 方法（insert, deleteById, updateById, selectById, selectList...）
    // 可扩展自定义方法
}

package com.example.demo.service;

import com.baomidou.mybatisplus.extension.service.IService;
import com.example.demo.entity.User;

public interface IUserService extends IService<User> {
    // 自定义业务方法可以在这里扩展
}

package com.example.demo.service.impl;

import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.example.demo.entity.User;
import com.example.demo.mapper.UserMapper;
import com.example.demo.service.IUserService;
import org.springframework.stereotype.Service;

@Service
public class UserServiceImpl extends ServiceImpl<UserMapper, User> implements IUserService {
    // 使用内置的 save/update/getById/list 等方法
}

package com.example.demo.controller;

import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.example.demo.entity.User;
import com.example.demo.service.IUserService;
import org.springframework.web.bind.annotation.*;

import javax.annotation.Resource;
import java.util.List;

@RestController
@RequestMapping("/users")
public class UserController {
    @Resource
    private IUserService userService;

    @GetMapping("/{id}")
    public User get(@PathVariable Long id) {
        return userService.getById(id);
    }

    @GetMapping
    public Page<User> list(@RequestParam(defaultValue = "1") long page,
                           @RequestParam(defaultValue = "10") long size,
                           @RequestParam(required = false) String name) {
        Page<User> p = new Page<>(page, size);
        LambdaQueryWrapper<User> wrapper = new LambdaQueryWrapper<>();
        if (name != null && !name.isEmpty()) {
            wrapper.like(User::getUsername, name);
        }
        return userService.page(p, wrapper);
    }

    @PostMapping
    public boolean create(@RequestBody User user) {
        return userService.save(user);
    }

    @PutMapping("/{id}")
    public boolean update(@PathVariable Long id, @RequestBody User user) {
        user.setId(id);
        return userService.updateById(user);
    }

    @DeleteMapping("/{id}")
    public boolean delete(@PathVariable Long id) {
        // 若启用了逻辑删除，则会被标记为已删除
        return userService.removeById(id);
    }
}

LambdaQueryWrapper<User> wrapper = new LambdaQueryWrapper<>();
wrapper.ge(User::getAge, 18)
       .le(User::getAge, 40)
       .like(User::getUsername, "张");

package com.example.demo.config;

import com.baomidou.mybatisplus.extension.plugins.MybatisPlusInterceptor;
import com.baomidou.mybatisplus.extension.plugins.inner.PaginationInnerInterceptor;
import com.baomidou.mybatisplus.extension.plugins.inner.OptimisticLockerInnerInterceptor;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class MybatisPlusConfig {

    @Bean
    public MybatisPlusInterceptor mybatisPlusInterceptor() {
        MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();
        // 分页（针对 MySQL）
        interceptor.addInnerInterceptor(new PaginationInnerInterceptor());
        // 乐观锁
        interceptor.addInnerInterceptor(new OptimisticLockerInnerInterceptor());
        // 其他插件（如防止全表更新等）可在此追加
        return interceptor;
    }
}

logging:
  level:
    com.baomidou.mybatisplus: debug
    org.mybatis: debug
    com.example.demo: debug