Struts2 控制标签(十一)对集合对象List进行排序

最新推荐文章于 2021-06-25 13:04:45 发布

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最新推荐文章于 2021-06-25 13:04:45 发布

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分类专栏： Struts2常用文章标签： Struts Java Bean JSP Apache

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本文介绍了一个使用Struts2框架进行用户信息排序的例子。通过创建JavaBean存储用户姓名和体重，利用Action处理数据并展示到JSP页面，最后通过自定义比较器实现了按体重排序的功能。

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1.新建JavaBean实例

package com.wl.control.Bean;

public class UserInfo {

    private String name;

    private int weight;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getWeight() {
        return weight;
    }

    public void setWeight(int weight) {
        this.weight = weight;
    }
}

2.新建Action实例

package com.wl.control.tagsAction;

import java.util.ArrayList;
import java.util.List;

import com.opensymphony.xwork2.ActionSupport;
import com.wl.control.Bean.UserInfo;

public class ShowSortList extends ActionSupport {

    private List listUserInfo=new ArrayList();

    public List getListUserInfo() {
        return listUserInfo;
    }

    public void setListUserInfo(List listUserInfo) {
        this.listUserInfo = listUserInfo;
    }

    @Override
    public String execute() throws Exception {

        UserInfo u1=new UserInfo();
        u1.setName("张三");
        u1.setWeight(140);

        UserInfo u2=new UserInfo();
        u2.setName("李四");
        u2.setWeight(110);

        UserInfo u3=new UserInfo();
        u3.setName("王五");
        u3.setWeight(120);

        listUserInfo.add(u1);
        listUserInfo.add(u2);
        listUserInfo.add(u3);
        return "showsortlist";
    }

}

3.新建排序类

package com.wl.operator.util;

import java.util.Comparator;

import com.wl.control.Bean.UserInfo;

public class SortWeight implements Comparator {

    public int compare(Object arg0, Object arg1) {

        if(((UserInfo)arg0).getWeight()>((UserInfo)arg1).getWeight()){
            return 1;
        }else{
            return -1;
        }
    }

}

注释：排序类要实现Comparator接口，并且重写compare()方法。
4.新建JSP文件

<%@ page language="java" import="java.util.*" pageEncoding="GB18030"%>
<%@ taglib uri="/struts-tags" prefix="s" %>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>

  <body>
     <s:bean name="com.wl.operator.util.SortWeight" var="sortref"></s:bean>
     <s:sort comparator="sortref" source="listUserInfo" var="newListUserInfo">
         <s:iterator var="userInfoRef" value="#attr.newListUserInfo">
            姓名：<s:property value="#userInfoRef.name"/>
            体重：<s:property value="#userInfoRef.weight"/>
           <br/>
         </s:iterator>
     </s:sort>
  </body>
</html>

5.修改struts.xml文件

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE struts PUBLIC 
    "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
    "http://struts.apache.org/dtds/struts-2.0.dtd">
<struts>
   <package name="Struts2.1" extends="struts-default">
       <action name="showsortlist" class="com.wl.control.tagsAction.ShowSortList">
           <result name="showsortlist">/controlTags/showsortlist.jsp</result>
       </action>
   </package>
</struts>

6.运行结果：

[img]http://dl.iteye.com/upload/attachment/380484/d899f7d5-fe01-3da7-8003-15075ac1d690.png[/img]