分頁框架(Pager-taglib)的使用及sitemesh的簡單使用

首先去Maven倉庫(http://mvnrepository.com)下載pager-taglib.jar包,它的官網貌似掛掉了.

固然了,說到分頁,固然得創建分頁bean,以下圖所示:

而後創建存放分頁請求參數的類SystemContext,該類中用到了ThreadLocal,它是一個跟當前線程相關的Map,它的key就是當前線程的名字

接着配置SystemContextFilter的過濾器,對全部請求都攔截.

1  <filter>
2       <filter-name>SystemContextFilter</filter-name>
3       <filter-class>com.scitc.page.web.SystemContextFilter</filter-class>
4   </filter>
5   <filter-mapping>
6       <filter-name>SystemContextFilter</filter-name>
7       <url-pattern>/*</url-pattern>
8   </filter-mapping>

View Code

在SystemContextFilter中對頁面請求參數進行處理,放入ThreadLocal中.

在DAO層,進行分頁處理

 1 package com.scitc.page.dao;
 2 
 3 import java.util.HashMap;
 4 import java.util.List;
 5 import java.util.Map;
 6 
 7 import org.apache.ibatis.session.SqlSession;
 8 
 9 import com.scitc.page.domain.Pager;
10 import com.scitc.page.domain.User;
11 import com.scitc.page.util.MyBatisUtil;
12 import com.scitc.page.util.SystemContext;
13 
14 public class UserDao {
15     public Pager<User> find(String name) {
16 
17         Map<String, Object> params = new HashMap<String, Object>();
18         if (name != null && !name.equals(""))
19             params.put("name", "%" + name + "%");
20         int pageSize = SystemContext.getPageSize();
21         int pageOffset = SystemContext.getPageOffset();
22         String order = SystemContext.getOrder();
23         String sort = SystemContext.getSort();
24         Pager<User> pages = new Pager<User>();
25         SqlSession session = null;
26         try {
27             session = MyBatisUtil.createSession();
28             params.put("pageSize", pageSize);
29             params.put("pageOffset", pageOffset);
30             params.put("sort", sort);
31             params.put("order", order);
32             List<User> datas = session.selectList(User.class.getName()+ ".find", params);
33             pages.setDatas(datas);
34             pages.setPageOffset(pageOffset);
35             pages.setPageSize(pageSize);
36             int totalRecord = session.selectOne(User.class.getName()+".find_count", params);
37             pages.setTotalRecord(totalRecord);
38         } finally {
39             MyBatisUtil.closeSession(session);
40         }
41         return pages;
42     }
43 }

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Mybatis中的SQL配置

 1 <?xml version="1.0" encoding="UTF-8"?>
 2 <!DOCTYPE mapper
 3   PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
 4   "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
 5   
 6 <mapper namespace="com.scitc.page.domain.User">
 7 
 8     <!-- 注意namespace不是別名,User的別名在mybatis.config.xml中的<typeAliases> -->
 9     
10     <insert id="add" parameterType="User">
11         INSERT INTO t_user (username,password,nickname) 
12         VALUES(#{username},#{password},#{nickname}) 
13     </insert>
14     <delete id="delete" parameterType="int">
15         delete from t_user where id=#{id}
16     </delete>
17     <update id="update" parameterType="User">
18         update t_user set username=#{username} where id=#{id}
19     </update>
20     <select id="load" parameterType="int" resultType="User">
21         select * from t_user where id=#{id}
22     </select>
23     <!-- List的返回結果仍可爲User -->
24     <select id="list" resultType="User">
25         select * from t_user
26     </select>
27     <!-- #{sx}會使用?進行替代 ，$(xx)會完整將字符串完成替代-->
28     <select id="find" resultType="User" parameterType="map">
29         select * from t_user
30         <!-- 動態SQL -->
31         <where>
32             <if test="name!=null"> (username like #{name} or nickname like #{name})</if>
33         </where>
34         
35         <if test="sort!=null">
36             order by ${sort}
37             <if test="order!=null">
38             ${order}
39             </if>
40         </if>
41         limit #{pageOffset},#{pageSize}
42     </select>
43     
44     <select id="find_count" parameterType="map" resultType="int">
45         select count(*) from t_user 
46         <if test="name!=null">where (username like #{name} or nickname like #{name})</if>
47     </select>
48 </mapper>

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爲何咱們要使用ThreadLocal呢?

主要是對跨層數據傳輸的處理,前面也提到了它是一個當前線程Map,因此使得跨層也能夠傳輸數據

好了,pager-taglib暫時說到這裏,接下來講說sitemesh

什麼是sitemesh呢?

它是一個網頁佈局和修飾的框架，利用它能夠將網頁的內容和頁面結構分離，以達到頁面結構共享的目的。

首先下載sitemesh的jar包,下載方法能夠去官網,也能夠去Maven倉庫

接下來配置sitemesh的過濾器

1 <filter>
2     <filter-name>sitemesh</filter-name>
3     <filter-class>com.opensymphony.sitemesh.webapp.SiteMeshFilter</filter-class>
4   </filter>
5 
6   <filter-mapping>
7     <filter-name>sitemesh</filter-name>
8     <url-pattern>/*</url-pattern>
9   </filter-mapping>

View Code

模版頁面的配置

 1 <%@ page language="java" contentType="text/html; charset=UTF-8"
 2     pageEncoding="UTF-8"%>
 3 <%@ taglib uri="http://www.opensymphony.com/sitemesh/decorator" prefix="decorator" %>
 4 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
 5 <html>
 6 <head>
 7 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
 8 <title><decorator:title default="歡迎使用xxx系統"/></title>
 9 <link rel="stylesheet" type="text/css" href="<%=request.getContextPath()%>/css/main.css"/>
10 <decorator:head/>
11 </head>
12 <body>
13 <a href="">其餘操做</a>
14 <hr/>
15 <h3 align="center"><decorator:title default="詳細信息"/></h3>
16 <decorator:body/>
17 <hr/>
18 <div align="center" class="distance">
19     55555555
20 </div>
21 <div align="center" class="footer">
22     CopyRight@2012-2015<br/>
23     scitc
24 </div>
25 </body>
26 </html>

View Code

最後效果如圖

 

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