MyBatis-Plus 分页插件使用示例

src/main/java
└─ com.neuedu.hisweb
   ├── config
   │   └── MybatisPlusConfig.java     // 配置类（已提供）
   ├── controller
   │   └── UserController.java        // 控制器
   ├── entity
   │   └── User.java                  // 实体类
   ├── mapper
   │   └── UserMapper.java            // Mapper 接口
   ├── service
   │   ├── UserService.java           // Service 接口
   │   └── impl
   │       └── UserServiceImpl.java   // Service 实现
   └── HisWebApplication.java         // 启动类

package com.neuedu.hisweb.entity;
 
import com.baomidou.mybatisplus.annotation.TableId;
import com.baomidou.mybatisplus.annotation.TableName;
import lombok.Data;
 
@Data
@TableName("user")  // 对应数据库表名
public class User {
    @TableId  // 主键注解
    private Long id;
    private String username;
    private String password;
    private Integer age;
    private String email;
}

package com.neuedu.hisweb.mapper;
 
import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.neuedu.hisweb.entity.User;
import org.apache.ibatis.annotations.Mapper;
 
@Mapper
public interface UserMapper extends BaseMapper<User> {
    // 继承 BaseMapper 后，自动拥有 CRUD 方法
    // 无需编写 selectById, insert, update, delete 等方法
}

package com.neuedu.hisweb.service;
 
import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.neuedu.hisweb.entity.User;
 
public interface UserService {
    // 分页查询用户列表
    IPage<User> getUserPage(Page<User> page);
    
    // 条件分页查询
    IPage<User> getUserPageByCondition(Page<User> page, String username);
}

package com.neuedu.hisweb.service.impl;
 
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.neuedu.hisweb.entity.User;
import com.neuedu.hisweb.mapper.UserMapper;
import com.neuedu.hisweb.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
 
@Service
public class UserServiceImpl extends ServiceImpl<UserMapper, User> implements UserService {
    
    @Autowired
    private UserMapper userMapper;
    
    // 分页查询所有用户
    @Override
    public IPage<User> getUserPage(Page<User> page) {
        // Page 参数包含页码和每页条数
        // 调用 BaseMapper 的 selectPage 方法，自动生成分页 SQL
        return userMapper.selectPage(page, null);  // null 表示无查询条件
    }
    
    // 条件分页查询
    @Override
    public IPage<User> getUserPageByCondition(Page<User> page, String username) {
        QueryWrapper<User> queryWrapper = new QueryWrapper<>();
        queryWrapper.like("username", username);  // 模糊查询用户名
        
        // 带条件的分页查询
        return userMapper.selectPage(page, queryWrapper);
    }
}

package com.neuedu.hisweb.controller;
 
import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.neuedu.hisweb.entity.User;
import com.neuedu.hisweb.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;
 
@RestController
@RequestMapping("/api/users")
public class UserController {
    
    @Autowired
    private UserService userService;
    
    // 分页查询用户列表
    @GetMapping("/page")
    public IPage<User> getUserPage(
            @RequestParam(defaultValue = "1") Integer pageNum,  // 页码，默认第1页
            @RequestParam(defaultValue = "10") Integer pageSize  // 每页条数，默认10条
    ) {
        // 创建分页对象
        Page<User> page = new Page<>(pageNum, pageSize);
        
        // 调用 Service 方法进行分页查询
        return userService.getUserPage(page);
    }
    
    // 条件分页查询
    @GetMapping("/page/condition")
    public IPage<User> getUserPageByCondition(
            @RequestParam(defaultValue = "1") Integer pageNum,
            @RequestParam(defaultValue = "10") Integer pageSize,
            @RequestParam(required = false) String username  // 可选参数：用户名
    ) {
        Page<User> page = new Page<>(pageNum, pageSize);
        
        // 带条件的分页查询
        return userService.getUserPageByCondition(page, username);
    }
}

package com.neuedu.hisweb.config;
 
import com.baomidou.mybatisplus.extension.plugins.MybatisPlusInterceptor;
import com.baomidou.mybatisplus.extension.plugins.inner.PaginationInnerInterceptor;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
 
/**
 * MyBatis-Plus 配置类
 */
@Configuration
public class MybatisPlusConfig {
 
    @Bean
    public MybatisPlusInterceptor mybatisPlusInterceptor() {
        // 创建 MyBatis-Plus 拦截器管理器
        MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();
        
        // 添加分页插件
        interceptor.addInnerInterceptor(new PaginationInnerInterceptor());
        
        // 可以添加其他插件（如乐观锁、逻辑删除等）
        // interceptor.addInnerInterceptor(new OptimisticLockerInnerInterceptor());
        
        return interceptor;
    }
}

package com.neuedu.hisweb;
 
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
 
@SpringBootApplication
@MapperScan("com.neuedu.hisweb.mapper")  // 扫描 Mapper 接口
public class HisWebApplication {
    public static void main(String[] args) {
        SpringApplication.run(HisWebApplication.class, args);
    }
}

GET http://localhost:8080/api/users/page?pageNum=1&pageSize=5 

GET http://localhost:8080/api/users/page/condition?pageNum=1&pageSize=5&username=张 

{
    "records": [ /* 当前页数据 */ ],
    "total": 100,      // 总记录数
    "size": 10,        // 每页条数
    "current": 1,      // 当前页码
    "pages": 10        // 总页数
}

// 可自定义分页插件参数
PaginationInnerInterceptor paginationInterceptor = new PaginationInnerInterceptor();
paginationInterceptor.setMaxLimit(1000L);  // 限制单页最大条数
paginationInterceptor.setOverflow(false);  // 溢出总页数后是否进行处理
interceptor.addInnerInterceptor(paginationInterceptor);

paginationInterceptor.setDbType(DbType.MYSQL);