Sample Code for implementing the paging function in the java ssm framework (oracle) and ssm sample code

Sample Code for implementing the paging function in the java ssm framework (oracle) and ssm sample code

The pagination feature of java web is described as follows:

Framework: ssm

Database: oracle

In other words, oracle's paging query is much more complicated than mysql. Here is a brief introduction:

Query the top 10 data records:

SELECT * FROM( SELECT ROWNUM WN,RN.* FROM (  SELECT   id,   title,   create_time as createTime,   musictor,   musictitle  FROM   krry_blog  ORDER BY create_time desc  )RN )WNWHERE WN <= 10 AND WN > 0

Complex syntax,

In the same result, the mysql syntax is: Use a LIMIT to solve the problem.

SELECT id, title, create_time as createTime, musictor, musictitleFROM krry_blog ORDER BY create_time descLIMIT 0,5

The establishment of the SSM framework is not much to mention. The previous blog has a detailed introduction. Here we will talk about implementing the java web paging function.

Js plug-ins: krry_page.js and jQuery

Er persistent layer:

BlogMapper. java

Package com. krry. mapper; import java. util. hashMap; import java. util. list; import com. krry. entity. params;/***** Mapper: database Operation * @ author krry * @ version 1.0.0 **/public interface BlogMapper {/*** query all blogs * @ param params * @ return */public List <HashMap <String, object> findBlogs (Params params);/***** calculate the number of blogs * com. krry. dao. admin * method name: countBlogs * @ author krry * @ param params * @ return int * @ exception * @ since 1.0.0 */public long countBlogs ();}

BlogMapper. xml

<? Xml version = "1.0" encoding = "UTF-8"?> <! DOCTYPE mapper PUBLIC "-// mybatis.org//DTD Mapper 3.0 //" http://mybatis.org/dtd/mybatis-3-mapper.dtd "> <mapper namespace =" com. krry. mapper. BlogMapper "> <! -- Query all blog information by page --> <select id = "findBlogs" resultType = "java. util. hashMap "parameterType =" Params "> SELECT * FROM (select rownum wn, RN. * FROM (SELECT id, title, create_time as createTime, musictor, musictitle FROM krry_blog order by create_time desc) RN) wn where wn <=#{ pageSize} and wn >#{ pageNo} </select> <! -- Query the number of blogs --> <select id = "countBlogs" resultType = "long"> SELECT count (*) FROM krry_blog </select> </mapper>

Service layer:

Interface Class: IBlogService. java

Package com. krry. service; import java. util. hashMap; import java. util. list; import javax. servlet. http. httpServletRequest; import org. apache. ibatis. annotations. param; import com. krry. entity. blog; import com. krry. entity. params;/*** service layer: Process business logic (implemented in impl) * @ author asusaad **/public interface IBlogService {/*** query all blogs by page * @ param params * @ return */public List <HashMap <String, object> findBlogs (Params params);/*** calculate the number of blogs * @ param params * @ return */public long countBlogs ();}

Impl implementation class: BlogService. java

Package com. krry. service. impl; import java. util. hashMap; import java. util. list; import org. springframework. beans. factory. annotation. autowired; import org. springframework. stereotype. service; import org. springframework. web. servlet. modelAndView; import com. krry. entity. params; import com. krry. mapper. blogMapper; import com. krry. service. IBlogService;/*** implement the service layer interface * @ author asusaad **/@ Servicepublic class BlogService implements IBlogService {@ Autowired private BlogMapper blogMapper; /*** query blog */public List <HashMap <String, Object> findBlogs (Params params) {// query blog information List <HashMap <String, object> blog = blogMapper. findBlogs (params); return blog;}/*** calculate the number of blogs * @ param params * @ return */public long countBlogs () {long coutBlogs = blogMapper. countBlogs (); return coutBlogs ;}}

Controller control layer:

KrryController. java

Package com. krry. controller; import java. util. hashMap; import java. util. list; import org. springframework. beans. factory. annotation. autowired; import org. springframework. stereotype. controller; import org. springframework. web. bind. annotation. requestMapping; import org. springframework. web. bind. annotation. responseBody; import org. springframework. web. servlet. modelAndView; import com. krry. entity. params; import com. krry. service. IBlogService;/*** KrryController * controller layer, which is used as request forwarding * @ author asusaad **/@ Controller // indicates multi-sample mode, the web layer returned by each user is a different public class KrryController {@ Autowired private IBlogService blogService;/*** homepage, and queries the * @ return */@ RequestMapping ("/index") page by page ") public ModelAndView index (Params params) {params. setPageNo (0); params. setPageSize (10); // query only 10 items at the beginning // call the business layer List <HashMap <String, Object> blogs = blogService. findBlogs (params); // query the number of blogs long coutBlogs = blogService. countBlogs (); ModelAndView modelAndView = new ModelAndView (); modelAndView. addObject ("blogs", blogs); modelAndView. addObject ("coutBlogs", coutBlogs); modelAndView. setViewName ("index"); return modelAndView;}/*** paging query of ajax requests * @ param params * @ return */@ ResponseBody @ RequestMapping ("/loadData ") public HashMap <String, Object> loadData (Params params) {HashMap <String, Object> map = new HashMap <String, Object> (); List <HashMap <String, object> blogs = blogService. findBlogs (params); map. put ("blogs", blogs); return map ;}}

Here there are two entity classes, which serve as the injection Blog for database query and two parameters for paging query Params:

Set the data parameter: pageNo (next page): the current page number * Number of pages to be displayed on the next page
PageSize (next page): the number of queries (pageNo) + the number to be displayed per page

In the database, it is WN <= pageSize and WN> pageNo to query paging data.

Blog. java

Package com. krry. entity;/***** User * @ author krry * @ version 1.0.0 **/public class Blog {// primary key private String id; // Blog title private String title; // music author private String musictor; // music title private String musictitle; // creation time private String createTime; public Blog (String id, String title, String musictor, String musictitle, string createTime) {this. id = id; this. title = title; this. musictor = musictor; this. musictitle = musictitle; this. createTime = createTime;} public String getId () {return id;} public void setId (String id) {this. id = id;} public String getTitle () {return title;} public void setTitle (String title) {this. title = title;} public String getMusictor () {return musictor;} public void setMusictor (String musictor) {this. musictor = musictor;} public String getMusictitle () {return musictitle;} public void setMusictitle (String musictitle) {this. musictitle = musictitle;} public String getCreateTime () {return createTime;} public void setCreateTime (String createTime) {this. createTime = createTime ;}}

Params. java

package com.krry.entity;/** *  * Params * @author krry * @version 1.0.0 * */public class Params { private Integer pageSize = 0; private Integer pageNo = 0;  public Integer getPageNo() {  return pageNo; } public void setPageNo(Integer pageNo) {  this.pageNo = pageNo; }  public Integer getPageSize() {  return pageSize; } public void setPageSize(Integer pageSize) {  this.pageSize = pageSize; }}

Web page index. jsp

<% @ Page language = "java" import = "java. util. * "pageEncoding =" UTF-8 "%> <% @ taglib uri =" http://java.sun.com/jsp/jstl/core "prefix =" c "%> <% String path = request. getContextPath (); String basePath = request. getScheme () + ": //" + request. getServerName () + ":" + request. getServerPort () + path + "/"; pageContext. setAttribute ("basePath", basePath); %> <! Doctype html> 
Paging:

The above is all the content of this article. I hope it will be helpful for your learning and support for helping customers.