MyBatis-Plus是MyBatis的增强工具，提供了一系列增强特性，包括分页查询。本文将详细介绍如何在Spring Boot项目中集成MyBatis-Plus，并利用其分页功能实现分页查询。
首先，需要在pom.xml文件中添加MyBatis-Plus和MyBatis的依赖：
<!-- MyBatis-Plus -->
<dependency>
<groupId>com.baomidou</groupId>
<artifactId>mybatis-plus-boot-starter</artifactId>
<version>最新版本</version>
</dependency>
<!-- MyBatis -->
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>最新版本</version>
</dependency>
在application.properties或application.yml中配置数据库连接信息：
spring:
datasource:
driver-class-name: com.mysql.cj.jdbc.Driver
url: jdbc:mysql://localhost:3306/your_database
username: your_username
password: your_password
创建一个配置类，使用@MapperScan注解指定Mapper接口的扫描路径：
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.context.annotation.Configuration;
@Configuration
@MapperScan("com.example.yourpackage.mapper")
public class MybatisPlusConfig {
// 可以在此配置MyBatis-Plus的其他特性，如逻辑删除、自动填充等
}
创建实体类和对应的Mapper接口，使用@TableName注解指定表名，@TableId注解指定主键：
import com.baomidou.mybatisplus.annotation.TableId;
import com.baomidou.mybatisplus.annotation.TableName;
import lombok.Data;
@Data
@TableName("user")
public class User {
@TableId
private Long id;
private String username;
private String email;
// 其他字段...
}
import com.baomidou.mybatisplus.core.mapper.BaseMapper;
public interface UserMapper extends BaseMapper<User> {
// 这里可以添加自定义的查询方法
}
创建服务层和控制器，使用Page类实现分页查询：
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import java.util.List;
@Service
public class UserService {
@Autowired
private UserMapper userMapper;
public PageUtils page(UserListReqVO reqVO) {
IPage<User page = userMapper.selectPage(
new Page<>(reqVO.getPageIndex(), reqVO.getPageSize()), reqVO);
return new PageUtils(page);
}
}
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
import java.util.List;
@RestController
public class UserController {
@Autowired
private UserService userService;
@GetMapping("/usersPage")
public AjaxResult getUsersByPage(@Valid UserListReqVO reqVO) {
PageUtils list = amcDoorplateService.page(reqVO);
return AjaxResult.Success("success",list);
}
}
@Data
@Builder
public class AjaxResult<T> {
public static class AjaxStatus {
public static final Integer Info = 100; // token有误
public static final Integer Success = 200; // 获取数据成功状态码
public static final Integer ERROR = 300; // 求失败
public static final Integer Warning = 400; //
public static final Integer UnAuthorized = 500; // 数据已存在
}
private Integer statusCode; //返回码
private String message; //回执信息
private T data; //回执数据
public static AjaxResult Success(String msg, Object obj) {
AjaxResult result = AjaxResult.builder().build();
result.setStatusCode(AjaxStatus.Success);
result.message = msg;
result.data = obj;
return result;
}
public static AjaxResult Error(Integer code, String msg) {
AjaxResult result = AjaxResult.builder().build();
result.setStatusCode(code);
result.message = msg;
return result;
}
public static AjaxResult Error(String msg) {
AjaxResult result = AjaxResult.builder().build();
result.setStatusCode(AjaxStatus.ERROR);
result.message = msg;
// new Exception().printStackTrace();
return result;
}
public static void Error(HttpServletResponse response) {
try {
response.setStatus(AjaxStatus.ERROR);
response.getOutputStream().close();
} catch (Exception e) {
}
}
public static AjaxResult UnAuthorized(String msg) {
AjaxResult result = AjaxResult.builder().build();
result.setStatusCode(AjaxStatus.UnAuthorized);
result.setMessage(msg);
result.setData("UnAuthorized");
return result;
}
}
public class PageUtils implements Serializable {
private static final long serialVersionUID = 1L;
/**
* 总记录数
*/
private int totalCount;
/**
* 每页记录数
*/
private int pageSize;
/**
* 总页数
*/
private int totalPage;
/**
* 当前页数
*/
private int currPage;
/**
* 列表数据
*/
private List<?> list;
/**
* 分页
* @param list 列表数据
* @param totalCount 总记录数
* @param pageSize 每页记录数
* @param currPage 当前页数
*/
public PageUtils(List<?> list, int totalCount, int pageSize, int currPage) {
this.list = list;
this.totalCount = totalCount;
this.pageSize = pageSize;
this.currPage = currPage;
this.totalPage = (int)Math.ceil((double)totalCount/pageSize);
}
public PageUtils(List<?> list, long totalCount, long pageSize, long currPage) {
this.list = list;
this.totalCount = (int)totalCount;
this.pageSize = (int)pageSize;
this.currPage = (int)currPage;
this.totalPage = (int)Math.ceil((double)totalCount/pageSize);
}
/**
* 分页
*/
public PageUtils(IPage<?> page) {
this.list = page.getRecords();
this.totalCount = (int)page.getTotal();
this.pageSize = (int)page.getSize();
this.currPage = (int)page.getCurrent();
this.totalPage = (int)page.getPages();
}
public int getTotalCount() {
return totalCount;
}
public void setTotalCount(int totalCount) {
this.totalCount = totalCount;
}
public int getPageSize() {
return pageSize;
}
public void setPageSize(int pageSize) {
this.pageSize = pageSize;
}
public int getTotalPage() {
return totalPage;
}
public void setTotalPage(int totalPage) {
this.totalPage = totalPage;
}
public int getCurrPage() {
return currPage;
}
public void setCurrPage(int currPage) {
this.currPage = currPage;
}
public List<?> getList() {
return list;
}
public void setList(List<?> list) {
this.list = list;
}
}
启动Spring Boot应用，访问/users接口即可进行分页查询：
curl http://localhost:8080/users
以上就是在Spring Boot中集成MyBatis-Plus实现分页查询的基本步骤。通过简单的配置和使用MyBatis-Plus提供的分页特性，可以轻松地在Spring Boot项目中实现分页查询功能。```