mybatis如何做分页处理

时间:2021-12-25 09:22:53

1.首先根据自己实际需求编写实体类

 import java.io.Serializable;

 public class User implements Serializable{  //最好将该实体类序列化

     private static final long serialVersionUID = 1L;

     private Integer id;
     private String name;
     private String birthday;
     private String gender;
     private String career;
     private String address;
     private String mobile;
     private String picPath;

     public User() {
     }

     public User(Integer id, String name, String birthday, String gender, String career, String address, String mobile,
             String picPath) {
         this.id = id;
         this.name = name;
         this.birthday = birthday;
         this.gender = gender;
         this.career = career;
         this.address = address;
         this.mobile = mobile;
         this.picPath = picPath;
     }

     public Integer getId() {
         return id;
     }
     public void setId(Integer id) {
         this.id = id;
     }
     public String getName() {
         return name;
     }
     public void setName(String name) {
         this.name = name;
     }
     public String getBirthday() {
         return birthday;
     }
     public void setBirthday(String birthday) {
         this.birthday = birthday;
     }
     public String getGender() {
         return gender;
     }
     public void setGender(String gender) {
         this.gender = gender;
     }
     public String getCareer() {
         return career;
     }
     public void setCareer(String career) {
         this.career = career;
     }
     public String getAddress() {
         return address;
     }
     public void setAddress(String address) {
         this.address = address;
     }
     public String getMobile() {
         return mobile;
     }
     public void setMobile(String mobile) {
         this.mobile = mobile;
     }
     public String getPicPath() {
         return picPath;
     }
     public void setPicPath(String picPath) {
         this.picPath = picPath;
     }

     @Override
     public String toString() {
         return "User [id=" + id + ", name=" + name + ", birthday=" + birthday + ", gender=" + gender + ", career="
                 + career + ", address=" + address + ", mobile=" + mobile + ", picPath=" + picPath + "
                 + "]";
     }
 }

2.编写分页所需要的通用bean,这是关键的一步。如果你用的是easyUI框架写的管理系统,currPage,PageSize,total,totalPage,rows这几个参数是必须的。

 import java.util.List;

 public class PageNationBean<T> {
     //请求参数
     private Integer currPage=1;//当前页
     private Integer PageSize=10;//页面数据条数

     //响应数据
     private Integer total;    //数据的总记录数
     private Integer totalPage;//总页数
     private List<T> rows;

     public PageNationBean() {
     }

     public PageNationBean(Integer currPage, Integer pageSize, Integer total, Integer totalPage, List<T> rows) {
         this.currPage = currPage;
         this.PageSize = pageSize;
         this.total = total;
         this.totalPage = totalPage;
         this.rows = rows;
     }

     public Integer getCurrPage() {
         return currPage;
     }
     public void setCurrPage(Integer currPage) {
         this.currPage = currPage;
     }
     public Integer getPageSize() {
         return PageSize;
     }
     public void setPageSize(Integer pageSize) {
         PageSize = pageSize;
     }
     public Integer getTotal() {
         return total;
     }
     public void setTotal(Integer total) {
         this.total = total;
     }
     public Integer getTotalPage() {
         return totalPage;
     }
     public void setTotalPage(Integer totalPage) {
         this.totalPage = totalPage;
     }
     public List<T> getRows() {
         return rows;
     }
     public void setRows(List<T> rows) {
         this.rows = rows;
     }
     @Override
     public String toString() {
         return "\n\tPageNationBean [currPage=" + currPage + ", PageSize=" + PageSize + ", total=" + total + ", totalPage="
                 + totalPage + ", rows=" + rows + "]";
     }

 }

3.数据库中建好需要测试的表,插入一定量的数据是肯定的

4.编写映射接口

public interface UserMapper {

    PageNationBean<User> getUsersByPagenation(PageNationBean<User> userBean);

}

5.编写映射所需的xml配置文件

 <?xml version="1.0" encoding="UTF-8" ?>
 <!DOCTYPE mapper
 PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
 "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
 <!-- 命名空间与映射接口的全类名一致 -->
 <mapper namespace="com.yc.us.mapper.UserMapper">

     <resultMap type="PageNationBean" id="PageNationBeanMap">
         <result column="pageSize" property="pageSize"/>
         <result column="currPage" property="currPage"/>
         <collection property="rows" column="{pageSize=pageSize,currPage=currPage}" select="getUsers"/>
     </resultMap>

     <!-- #是采用占用符    $是直接取到值 -->
     <select id="getUsersByPagenation" parameterType="PageNationBean" resultMap="PageNationBeanMap">
         select count(1) total,ceil(count(1)/${pageSize}) totalPage,${pageSize} pageSize,${currPage} currPage from profile
     </select>
     <select id="getUsers" resultType="User">
         select * from
         (select m.*,rownum rn from
         (select * from profile) m where ${currPage}*${pageSize} >=rownum)
         where rn > (${currPage}-1)*${pageSize}
     </select>

 </mapper>

6.根据自己实际需求写一个测试类,进行实际测试