javaweb分页查询实现
Javaweb分页技术实现
分页技术就是通过SQL语句(如下)来获取数据，具体实现看下面代码
//分页查询语句 select * from 表名 where limit page , count; 和 //获取表中的总数据，确定页数 select count(*) from 表名;
不说废话直接上代码
前端代码：
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Title</title> <script src="js/jquery-3.3.1.js"></script> <link rel="stylesheet" href="css/bootstrap.min.css"> </head> <body> <div class="container"> <div class="row clearfix"> <div class="col-md-12 column"> <table class="table table-bordered table-hover"> <thead> <tr> <th>City_ID</th> <th>City_EN</th> <th>City_CN</th> <th>Country_code</th> <th>Country_EN</th> <th>Country_CN</th> <th>Province_EN</th> <th>Province_CN</th> </tr> </thead> <tbody id="tbody"> </tbody> </table> <!--分页--> 第<span id="paging">1</span>页/ 共<span id="countPage">1</span>页/ <a id="homePage">Home</a>/ <a id="prevPage">Prev</a>/ <a id="nextPage">Next</a>/ 转到第： <input type="text" style="width: 2em" id="pageNum"> 页 <a id="goPage">Go</a> </div> </div> </div> </body> <script> $(function () { //页面初始化 （显示第一页） selectPage(1); home(); prev(); next(); goPage(); }) function selectPage(pageCode) { //分页查询 pageCode：页数 $.ajax("getCity",{ type:"get", data:{"currenPage":pageCode}, success:function (data) { $("#tbody").html(""); //总页数 $("#countPage").text(data.totalPage); $.each(data.pageData,function (index,obj) { var clazz=""; if(index%2==0){ clazz="success"; } $("#tbody").append( "<tr class='"+clazz+"'>\n" + "<td>"+obj.cityId+"</td>\n" + "<td>"+obj.cityEn+"</td>\n" + "<td>"+obj.cityCn+"</td>\n" + "<td>"+obj.countryCode+"</td>\n" + "<td>"+obj.countryEn+"</td>\n" + "<td>"+obj.countryCn+"</td>\n" + "<td>"+obj.provinceEn+"</td>\n" + "<td>"+obj.provinceCn+"</td>\n" + "</tr>" ); }) } }); } //第一页 function home() { $("#homePage").on("click",function () { $("#paging").text(1); selectPage(1); }) } //上一页 function prev() { $("#prevPage").on("click",function () { var prevText=$("#paging").text(); var prevNum=parseInt(prevText); prevNum=prevNum-1; if(prevNum<=1){ selectPage(1); $("#paging").text(1); return; } $("#paging").text(prevNum); selectPage(prevNum); }) } //下一页 function next() { $("#nextPage").on("click",function () { //获取文本的值 页数 var prevText=$("#paging").text(); //类型转换 var prevNum=parseInt(prevText); //总页数 var countText=$("#countPage").text(); //类型转换 var countNum = parseInt(countText); //页数加1 prevNum=prevNum+1; //判断超出了总页码 if(prevNum>=countNum){ selectPage(countNum); $("#paging").text(countNum); return; } //设置网页增加的值 $("#paging").text(prevNum); //调用分页查询 selectPage(prevNum); }) } //去到几页 function goPage() { $("#goPage").on("click",function () { var pageNum=parseInt($("#pageNum").val()); var countPage=parseInt($("#countPage").text()) //判断超出了总页码 if(pageNum>=countPage){ selectPage(countPage); $("#paging").text(countPage); $("#pageNum").val(countPage); return; } //判断低于了总页码 if(pageNum<=1){ selectPage(1); $("#paging").text(1); $("#pageNum").val(1); return; } selectPage(pageNum); $("#paging").text(pageNum); }) } </script> </html>
后台servlet代码：
/** * @author hh * @Date 2018/9/12 */ @WebServlet("/getCity") public class PageServlet extends HttpServlet { @Override protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { //获取当前页参数，第一次访问为空 String currPage = req.getParameter("currenPage"); // 判断，如果为空，则设置为1 if (currPage == null || "".equals(currPage.trim())) { currPage = "1"; } //调用service返回分页类实例 PageBean<City> pageBean=new PageService().getPage(currPage); //设置相应文本类型 resp.setContentType("application/json;charset=utf-8"); //响应前端 resp.getWriter().print(new Gson().toJson(pageBean)); } }
City 实体类：
package edu.nf.demo.entity; /** * @author hh * @Date 2018/9/12 */ public class City { private String cityId; private String cityEn; private String cityCn; private String countryCode; private String countryEn; private String countryCn; private String provinceEn; private String provinceCn; public String getCityId() { return cityId; } public void setCityId(String cityId) { this.cityId = cityId; } public String getCityEn() { return cityEn; } public void setCityEn(String cityEn) { this.cityEn = cityEn; } public String getCityCn() { return cityCn; } public void setCityCn(String cityCn) { this.cityCn = cityCn; } public String getCountryCode() { return countryCode; } public void setCountryCode(String countryCode) { this.countryCode = countryCode; } public String getCountryEn() { return countryEn; } public void setCountryEn(String countryEn) { this.countryEn = countryEn; } public String getCountryCn() { return countryCn; } public void setCountryCn(String countryCn) { this.countryCn = countryCn; } public String getProvinceEn() { return provinceEn; } public void setProvinceEn(String provinceEn) { this.provinceEn = provinceEn; } public String getProvinceCn() { return provinceCn; } public void setProvinceCn(String provinceCn) { this.provinceCn = provinceCn; } }
自己写的一个类，专门用于分页查询用的：
package edu.nf.demo.entity; import java.util.List; /** * @author hh * @Date 2018/9/12 */ public class PageBean<T> { /** * 当前页， 默认显示第一页 */ private Integer currntPage = 1; /** * 查询返回的行数（每页显示的行数），默认每页显示10行 */ private int pageCount = 10; /** * 总记录数 */ private int totalCount; /** * 总页数 = 总记录数/每页显示的行数（+1） */ private int totalPage; /** * 分页查询的数据,运用泛型，可以重复利用 */ private List<T> pageData; public int getTotalPage() { if (totalCount % pageCount == 0) { totalPage = totalCount / pageCount; } else { totalPage = totalCount / pageCount + 1; } return totalPage; } public void setTotalPage(int totalPage) { this.totalPage = totalPage; } public int getCurrntPage() { return currntPage; } public void setCurrntPage(int currntPage) { this.currntPage = currntPage; } public int getPageCount() { return pageCount; } public void setPageCount(int pageCount) { this.pageCount = pageCount; } public int getTotalCount() { return totalCount; } public void setTotalCount(int totalCount) { this.totalCount = totalCount; } public List<T> getPageData() { return pageData; } public void setPageData(List<T> pageData) { this.pageData = pageData; } }
后台service，逻辑业务层：
/** * @author hh * @Date 2018/9/12 */ public class PageService { public PageBean getPage(String currPage){ //类型转换 当前页数 Integer currenPage = Integer.valueOf(currPage); //实例化分页类 PageBean<City> pageBean = new PageBean(); //实例化CityDaoImpl类 CityDaoImpl cityDao=new CityDaoImpl(); //数据库第几行开始查询 int startPage=(currenPage-1)*pageBean.getPageCount(); //查询多少行数据 分页类里默认30行 int selectCount=pageBean.getPageCount(); //查询数据库获取分页返回的数据 : select * from regional_info limit startPage,selectCount List<City> list=cityDao.listCity(startPage,selectCount); //获取总数 int cityCount=cityDao.getCityCount(); //设置查询的数据 pageBean.setPageData(list); //共多少行 pageBean.setTotalCount(cityCount); //设置总页数 pageBean.setTotalPage(cityCount/pageBean.getPageCount()+1); return pageBean; } }
