当前要闻：springboot实现分页功能的完整代码

脚本之家   2023-04-16 05:51:48

目录
1.分页功能的作用2.建立测试数据库3.分页功能返回的结果封装4.分页功能代码具体实现4.1数据层4.2业务层4.3控制层5.jqGrid分页插件总结

1.分页功能的作用

分页功能作为各类网站和系统不可或缺的部分（例如百度搜索结果的分页等），当一个页面数据量大的时候分页作用就体现出来的，其作用有以下5个。

（1）减少系统资源的消耗


(资料图)

（2）提高数据库的查询性能

（3）提升页面的访问速度

（4）符合用户的浏览习惯

（5）适配页面的排版

2.建立测试数据库

由于需要实现分页功能，所需的数据较多

DROP TABLE IF EXISTS tb_user;

CREATE TABLE tb_user (
    id int(11) NOT NULL AUTO_INCREMENT COMMENT "主键id",
    name varchar(100) NOT NULL DEFAULT "" COMMENT "登录名",
    password varchar(100) NOT NULL DEFAULT "" COMMENT "密码",
    PRIMARY KEY (id) USING BTREE
) ENGINE = InnoDB CHARACTER SET = utf8;

insert into tb_user (id,name,password)
value (1,"C","123456"),
(2,"C++","123456"),
(3,"Java","123456"),
(4,"Python","123456"),
(5,"R","123456"),
(6,"C#","123456");

insert into tb_user (id,name,password) value (7,"test1","123456");
insert into tb_user (id,name,password) value (8,"test2","123456");
insert into tb_user (id,name,password) value (9,"test3","123456");
insert into tb_user (id,name,password) value (10,"test4","123456");
insert into tb_user (id,name,password) value (11,"test5","123456");
insert into tb_user (id,name,password) value (12,"test6","123456");
insert into tb_user (id,name,password) value (13,"test7","123456");
insert into tb_user (id,name,password) value (14,"test8","123456");
insert into tb_user (id,name,password) value (15,"test9","123456");
insert into tb_user (id,name,password) value (16,"test10","123456");
insert into tb_user (id,name,password) value (17,"test11","123456");
insert into tb_user (id,name,password) value (18,"test12","123456");
insert into tb_user (id,name,password) value (19,"test13","123456");
insert into tb_user (id,name,password) value (20,"test14","123456");
insert into tb_user (id,name,password) value (21,"test15","123456");
insert into tb_user (id,name,password) value (22,"test16","123456");
insert into tb_user (id,name,password) value (23,"test17","123456");
insert into tb_user (id,name,password) value (24,"test18","123456");
insert into tb_user (id,name,password) value (25,"test19","123456");
insert into tb_user (id,name,password) value (26,"test20","123456");
insert into tb_user (id,name,password) value (27,"test21","123456");
insert into tb_user (id,name,password) value (28,"test22","123456");
insert into tb_user (id,name,password) value (29,"test23","123456");
insert into tb_user (id,name,password) value (30,"test24","123456");
insert into tb_user (id,name,password) value (31,"test25","123456");
insert into tb_user (id,name,password) value (32,"test26","123456");
insert into tb_user (id,name,password) value (33,"test27","123456");
insert into tb_user (id,name,password) value (34,"test28","123456");
insert into tb_user (id,name,password) value (35,"test29","123456");
insert into tb_user (id,name,password) value (36,"test30","123456");
insert into tb_user (id,name,password) value (37,"test31","123456");
insert into tb_user (id,name,password) value (38,"test32","123456");
insert into tb_user (id,name,password) value (39,"test33","123456");
insert into tb_user (id,name,password) value (40,"test34","123456");
insert into tb_user (id,name,password) value (41,"test35","123456");
insert into tb_user (id,name,password) value (42,"test36","123456");
insert into tb_user (id,name,password) value (43,"test37","123456");
insert into tb_user (id,name,password) value (44,"test38","123456");
insert into tb_user (id,name,password) value (45,"test39","123456");
insert into tb_user (id,name,password) value (46,"test40","123456");
insert into tb_user (id,name,password) value (47,"test41","123456");
insert into tb_user (id,name,password) value (48,"test42","123456");
insert into tb_user (id,name,password) value (49,"test43","123456");
insert into tb_user (id,name,password) value (50,"test44","123456");
insert into tb_user (id,name,password) value (51,"test45","123456");

3.分页功能返回的结果封装

新建一个util包并在包中新建Result通用结果类，代码如下：

package ltd.newbee.mall.entity;

public class User {
    private Integer id;
    private String name;
    private String password;

    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 getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }
}

后端接口返回的数据会根据以上格式进行数据封装，包括业务码、返回信息、实际的数据结果。这个格式是开发人员自行设置的，如果有其他更好的方案也可以进行适当的调整。

在util包中新建PageResult通用结果类，代码如下：

package ltd.newbee.mall.util;

import java.util.List;

/**
 * 分页工具类
 */
public class PageResult {
    //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;

    /**
     *
     * @param totalCount 总记录数
     * @param pageSize 每页记录数
     * @param currPage 当前页数
     * @param list 列表数据
     */
    public PageResult(int totalCount, int pageSize, int currPage, List list) {
        this.totalCount = totalCount;
        this.pageSize = pageSize;
        this.currPage = currPage;
        this.list = list;
        this.totalPage = (int) Math.ceil((double) totalCount / pageSize);
    }

    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;
    }
}

4.分页功能代码具体实现

4.1数据层

在UserDao接口中新增两个方法findUsers()和getTotalUser()，代码如下所示：

/**
     * 返回分页数据列表
     * 
     * @param pageUtil
     * @return
     */
    List findUsers(PageQueryUtil pageUtil);

    /**
     * 返回数据总数
     * 
     * @param pageUtil
     * @return
     */
    int getTotalUser(PageQueryUtil pageUtil);

在UserMapper.xml文件中新增这两个方法的映射语句，代码如下所示：

4.2业务层

新建service包，并新增业务类UserService，代码如下所示：

import ltd.newbee.mall.dao.UserDao;
import ltd.newbee.mall.entity.User;
import ltd.newbee.mall.util.PageResult;
import ltd.newbee.mall.util.PageQueryUtil;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

@Service
public class UserService {

    @Autowired
    private UserDao userDao;

    public PageResult getUserPage(PageQueryUtil pageUtil){
        //当前页面中的数据列表
        List users = userDao.findUsers(pageUtil);
        //数据总条数，用于计算分页数据
        int total = userDao.getTotalUser(pageUtil);
        //分页信息封装
        PageResult pageResult = new PageResult(users,total,pageUtil.getLimit(),pageUtil.getPage());
        return pageResult;
    }
}

首先根据当前页面和每页条数查询当前页的数据集合，然后调用select count（*）语句查询数据的总条数用于计算分页数据，最后将获取的数据封装到PageResult对象中并返回给控制层。

4.3控制层

在controller包中新建PageTestController类，用于实现分页请求的处理并返回查询结果，代码如下所示：

@RestController
@RequestMapping("users")
public class PageTestController {

    @Autowired
    private UserService userService;

    //分页功能测试
    @RequestMapping(value = "/list",method = RequestMethod.GET)
    public Result list(@RequestParam Map params){
        Result result = new Result();
        if (StringUtils.isEmpty(params.get("page"))||StringUtils.isEmpty(params.get("limit"))){
            //返回错误码
            result.setResultCode(500);
            //错误信息
            result.setMessage("参数异常！");
            return result;
        }
        //封装查询参数
        PageQueryUtil queryParamList = new PageQueryUtil(params);
        //查询并封装分页结果集
        PageResult userPage = userService.getUserPage(queryParamList);
        //返回成功码
        result.setResultCode(200);
        result.setMessage("查询成功");
        //返回分页数据
        result.setData(userPage);
        return result;
    }
}

分页功能的交互流程：前端将所需页码和条数参数传输给后端，后端在接收分页请求后对分页参数进行计算，并利用MySQL的limit关键字查询对应的记录，在查询结果被封装后返回给前端。在TestUserControler类上使用的是@RestController注解，该注解相当于@ResponseBody＋@Controller的组合注解。

5.jqGrid分页插件

jqGrid是一个用来显示网格数据的jQuery插件。开发人员通过使用jqGrid可以轻松实现前端页面与后台数据的Ajax异步通信并实现分页功能。同时，jqGrid是一款代码开源的分页插件，源码也一直处于迭代更新的状态中。

下载地址：jqGrid

下载jqGrid后解压文件，将解压的文件直接拖进项目的static目录下

以下是jqGrid实现分页的步骤：

首先，在前端页面代码中引入jqGrid分页插件所需的源文件，代码如下所示：



<script src="http://s3.pstatp.com/cdn/expire-1-M/jquery/3.3.1/jquery.min.js"></script>

<script src="plugins/jqgrid-5.8.2/grid.locale-cn.js"></script>
<script src="plugins/jqgrid-5.8.2/jquery.jqGrid.min.js"></script>

其次，在页面中需要展示分页数据的区域添加用于jqGrid初始化的代码：

最后，调用jqGrid分页插件的jqGrid()方法渲染分页展示区域，代码如下所示：

jqGrid()方法中的参数及含义如图所示。

jqGrid前端页面测试：

在resources/static目中新建jqgrid-page-test.html文件，代码如下所示：




    
    jqGrid分页测试
    
    
    




    
    

    
    





<script src="http://s3.pstatp.com/cdn/expire-1-M/jquery/3.3.1/jquery.min.js"></script>

<script src="plugins/jqgrid-5.8.2/grid.locale-cn.js"></script>
<script src="plugins/jqgrid-5.8.2/jquery.jqGrid.min.js"></script>
<script src="jqgrid-page-test.js"></script>

jqGrid初始化

在resources/static目录下新建jqgrid-page-test.js文件，代码如下所示：

$(function () {
    $("#jqGrid").jqGrid({
        url: "users/list",
        datatype: "json",
        colModel: [
            {label: "id",name: "id", index: "id", width: 50, hidden: true,key:true},
            {label: "登录名",name: "name",index: "name", sortable: false, width: 80},
            {label: "密码字段",name: "password",index: "password", sortable: false, width: 80}
        ],
        height: 485,
        rowNum: 10,
        rowList: [10,30,50],
        styleUI: "Bootstrap",
        loadtext: "信息读取中...",
        rownumbers: true,
        rownumWidth: 35,
        autowidth: true,
        multiselect: true,
        pager: "#jqGridPager",
        jsonReader:{
            root: "data.list",
            page: "data.currPage",
            total: "data.totalCount"
        },
        prmNames:{
            page: "page",
            rows: "limit",
            order: "order"
        },
        gridComplete: function () {
            //隐藏grid底部滚动条
            $("#jqGrid").closest(".ui-jqgrid-bdiv").css({"overflow-x": "hidden"});
        }
    });
    $(window).resize(function () {
        $("jqGrid").setGridWidth($(".card-body").width());
    });
});

总结

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