分頁功能作為各類網站和系統不可或缺的部分(例如百度搜尋結果的分頁等),當一個頁面資料量大的時候分頁作用就體現出來的,其作用有以下5個。
(1)減少系統資源的消耗
(2)提高資料庫的查詢效能
(3)提升頁面的存取速度
(4 )符合使用者的瀏覽習慣
(5)適配頁面的排版
由於需要實現分頁功能,所需的資料較多
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');
新建一個util套件並在套件中新建Result通用結果類,程式碼如下:
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; } }
後端介面傳回的數據會根據以上格式進行資料封裝,包括業務碼、傳回資訊、實際的資料結果。這個格式是開發人員自行設定的,如果有其他更好的方案也可以進行適當的調整。
在util套件中新建PageResult通用結果類,程式碼如下:
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; } }
#在UserDao在介面中新增兩個方法findUsers()和getTotalUser(),程式碼如下所示:
/** * 返回分页数据列表 * * @param pageUtil * @return */ List<User> findUsers(PageQueryUtil pageUtil); /** * 返回数据总数 * * @param pageUtil * @return */ int getTotalUser(PageQueryUtil pageUtil);
在UserMapper.xml檔案中新增這兩個方法的對應語句,程式碼如下所示:
<!--分页--> <!--查询用户列表--> <select id="findUsers" parameterType="Map" resultMap="UserResult"> select id,name,password from tb_user order by id desc <if test="start!=null and limit!=null"> limit #{start}.#{limit} </if> </select> <!--查询用户总数--> <select id="getTotalUser" parameterType="Map" resultType="int"> select count(*) from tb_user </select>
新service包,並新增業務類別UserService,程式碼如下所示:
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<User> 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; } }
首先根據目前頁面和每頁條數查詢目前頁的資料集合,然後呼叫select count(*)語句查詢資料的總條數用於計算分頁數據,最後將取得的資料封裝到PageResult物件中並傳回給控制層。
在controller包中新建PageTestController類,用於實現分頁請求的處理並傳回查詢結果,程式碼如下所示:
@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<String,Object> 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; } }
分頁功能的互動流程:前端將所需頁碼和條數參數傳送給後端,後端在接收分頁請求後對分頁參數進行計算,並利用MySQL的limit關鍵字查詢對應的記錄,在查詢結果被封裝後傳回給前端。在TestUserControler類別上使用的是@RestController註解,相當於@ResponseBody+@Controller的組合註解。
jqGrid是一個用來顯示網格資料的jQuery外掛程式。開發人員透過使用jqGrid可以輕鬆實現前端頁面與後台資料的Ajax非同步通訊並實現分頁功能。同時,jqGrid是一款程式碼開源的分頁插件,原始碼也一直處於迭代更新的狀態。
下載地址:jqGrid
下載jqGrid後解壓縮文件,將解壓縮的文件直接拖進項目的static目錄下
##以下是jqGrid實作分頁的步驟:首先,在前端頁面程式碼中引入jqGrid分頁外掛程式所需的來源文件,程式碼如下所示:<link href="plugins/jqgrid-5.8.2/ui.jqgrid-bootstrap4.css" rel="external nofollow" rel="stylesheet"/> <!--jqGrid依赖jQuery,因此需要先引入jquery.min.js文件,下方地址为字节跳动提供的cdn地址--> <script src="http://s3.pstatp.com/cdn/expire-1-M/jquery/3.3.1/jquery.min.js"></script> <!--grid.locale-cn.js为国际化所需的文件,-cn表示中文--> <script src="plugins/jqgrid-5.8.2/grid.locale-cn.js"></script> <script src="plugins/jqgrid-5.8.2/jquery.jqGrid.min.js"></script>
<!--jqGrid必要DOM,用于创建表格展示列表数据--> <table id="jqGrid" class="table table-bordered"></table> <!--jqGrid必要DOM,分页信息区域--> <div id="jqGridPager"></div>
jqGrid()方法中的參數及意義如圖所示。 jqGrid前端頁面測試:在resources/static目中新建jqgrid-page-test.html文件,程式碼如下:
<!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <title>jqGrid分页测试</title> <!--引入bootstrap样式文件--> <link rel="stylesheet" href="/static/bootstrap-5.3.0-alpha3-dist/css/bootstrap.css" rel="external nofollow" /> <link href="jqGrid-5.8.2/css/ui.jqgrid-bootstrap4.css" rel="external nofollow" rel="stylesheet"/> </head> <body> <div > <!--数据展示列表,id为jqGrid--> <table id="jqGrid" class="table table-bordered"></table> <!--分页按钮展示区--> <div id="jqGridPager"></div> </div> </body> <!--jqGrid依赖jQuery,因此需要先引入jquery.min.js文件,下方地址为字节跳动提供的cdn地址--> <script src="http://s3.pstatp.com/cdn/expire-1-M/jquery/3.3.1/jquery.min.js"></script> <!--grid.locale-cn.js为国际化所需的文件,-cn表示中文--> <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> </html>
$(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()); }); });
以上是springboot分頁功能怎麼實現的詳細內容。更多資訊請關注PHP中文網其他相關文章!