public class MyPageHelper {
// 调用pageInfo插件内的方法 开启分页 需要传入一个起始页的值和每页显示的条数
public static void startPage(PageRequest pageRequest) {
PageHelper.startPage(pageRequest.getPageNum(),pageRequest.getPageSize());
}
// 封装结果集
public static PageResult getPageResult(List content) {
// 创建分页对象 将结果传入对象中 pageInfo对象中生成信息
PageInfo pageInfo = new PageInfo<>(content);
// 创建返回的对象
PageResult pageResult = new PageResult();
// 获取总页数
pageResult.setTotal(pageInfo.getTotal());
// 获取结果
pageResult.setContent(pageInfo.getList());
// 获取总页数
pageResult.setPages(pageInfo.getPages());
// 获取起始页数
pageResult.setPageNum(pageInfo.getPageNum());
// 获取每页显示的条数
pageResult.setPageSize(pageInfo.getPageSize());
// 返回结果
return pageResult;
}
}
public class PageRequest {
/**
*页数
*/
private int pageNum;
/**
* 每页的信息的个数
*/
private int pageSize;
public PageRequest() {
}
public PageRequest(int pageNum, int pageSize) {
this.pageNum = pageNum;
this.pageSize = pageSize;
}
/**
* 获取
* @return pageNum
*/
public int getPageNum() {
return pageNum;
}
/**
* 设置
* @param pageNum
*/
public void setPageNum(int pageNum) {
this.pageNum = pageNum;
}
/**
* 获取
* @return pageSize
*/
public int getPageSize() {
return pageSize;
}
/**
* 设置
* @param pageSize
*/
public void setPageSize(int pageSize) {
this.pageSize = pageSize;
}
public String toString() {
return "PageRequest{pageNum = " + pageNum + ", pageSize = " + pageSize + "}";
}
}
public class PageResult { /** *页数 */ private int pageNum; /** * 每页的信息的个数 */ private int pageSize; /** * 总条数 */ private Long total; /** * 总页数 */ private int pages; /** * 结果集 */ private List<?> content; public PageResult() { } public PageResult(int pageNum, int pageSize, Long total, int pages, List<?> content) { this.pageNum = pageNum; this.pageSize = pageSize; this.total = total; this.pages = pages; this.content = content; } /** * 返回结果调用的方法 */ public static PageResult getPageResult(List content,PageRequest pageRequest,Long total) { // 创建返回的对象 PageResult pageResult = new PageResult(); // 将分页后查询到的结果放入对象中 pageResult.setContent(content); // 将起始页放入对象中 pageResult.setPageNum(pageRequest.getPageNum()); // 将每页显示的条数放入对象中 pageResult.setPageSize(pageRequest.getPageSize()); // 将总条数放入对象中 pageResult.setTotal(total); // 返回结果 return pageResult; } /** * 获取 * @return pageNum */ public int getPageNum() { return pageNum; } /** * 设置 * @param pageNum */ public void setPageNum(int pageNum) { this.pageNum = pageNum; } /** * 获取 * @return pageSize */ public int getPageSize() { return pageSize; } /** * 设置 * @param pageSize */ public void setPageSize(int pageSize) { this.pageSize = pageSize; } /** * 获取 * @return total */ public Long getTotal() { return total; } /** * 设置 * @param total */ public void setTotal(Long total) { this.total = total; } /** * 获取 * @return pages */ public int getPages() { return pages; } /** * 设置 * @param pages */ public void setPages(int pages) { this.pages = pages; } /** * 获取 * @return content */ public List<?> getContent() { return content; } /** * 设置 * @param content */ public void setContent(List<?> content) { this.content = content; } public String toString() { return "PageResult{pageNum = " + pageNum + ", pageSize = " + pageSize + ", total = " + total + ", pages = " + pages + ", content = " + content + "}"; } }
三个实体类写完了后，接下来就是mapper层的编写
@Mapper
public interface StudentDao extends BaseMapper<Student> {
List<Student> selectAllChd(PageRequest pageRequest);
}
service的编写与实现类的编写
public interface StudentService extends IService<Student> {
List<Student> selectAllChd(PageRequest pageRequest);
}
@Service public class StudentServiceImpl extends ServiceImpl<StudentDao, Student> implements StudentService { @Resource StudentDao studentDao; @Override public List<Student> selectAllChd(PageRequest pageRequest) { return studentDao.selectAllChd(pageRequest); } }
再接着是controller的编写
@GetMapping("/query")
@ResponseBody
public PageResult queryList() {//分页写出来了
System.out.println("进来了query");
PageRequest pageRequest=new PageRequest(1,3);
int pageNum = pageRequest.getPageNum();
pageRequest.setPageNum((pageRequest.getPageSize()*(pageRequest.getPageNum()-1)));
List<Student> carManagerEntityList =studentService.selectAllChd(pageRequest);
pageRequest.setPageNum(pageNum);
Long total = studentService.count();
return PageResult.getPageResult(carManagerEntityList,pageRequest,total);
}
mybatis-plus虽然使用起来方便，但是俩表映射就不能使用自带的分页了，所以需要小伙伴自己手动写，下面是映射语句
<resultMap type="com.cskt.entity.Student" id="StudentMap">
<result property="sId" column="s_id" jdbcType="INTEGER"/>
<result property="sName" column="s_name" jdbcType="VARCHAR"/>
<result property="sSex" column="s_sex" jdbcType="VARCHAR"/>
<association property="sClass" resultMap="ClassMap"></association>
</resultMap>
<resultMap id="ClassMap" type="com.cskt.entity.StuClass">
<id property="cId" column="c_id"></id>
<result property="cName" column="c_name"></result>
</resultMap>
<select id="selectAllChd" resultMap="StudentMap">
SELECT * FROM `student` as stu join stu_class as sts on stu.s_class=sts.c_id limit #{pageNum} ,#{pageSize}
</select>
项目结构如下
查询效果如下，分页成功，并且俩表映射成功，希望可以帮助到各位小伙伴
