Struts2学习笔记(7)-访问Web元素

2019-11-26 14:12:32

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常用的Web元素有：request、session、application等，而我们一般使用session较多，Struts2如何访问web元素呢？这个是非常重要的内容，因为它能完成程序后台和用户的数据交互，下面以注册为例演示其过程：

1、index.jsp文件

<%@ page language="java" contentType="text/html; charset=UTF-8"   pageEncoding="UTF-8"%> <%  String path = request.getContextPath(); String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/"; %> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <base href="<%=basePath %>"/> <title>Insert title here</title> </head> <body> <h1>演示</h1> <form action="user/user02!register" method="post"> 姓名：<input type="text" name="user.name"></input> <br/> 密码：<input type="text" name="user.password"></input> <br/> <input type="submit" value="注册"/> </form> </body> </html>

功能很简单--即用户输入用户名和密码，然后后台可以获得，然后注册成功后显示给用户

2、struts.xml 配置

<?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>   <constant name="struts.devMode" value="true" />   <package name="front" namespace="/user" extends="struts-default">      <action name="user*" class="com.myservice.web.UserAction{1}">       <result>/success.jsp</result>       <result name="error">/error.jsp</result>     </action>   </package> </struts>

可以有两种方式完成这个功能

3、第一种（UserAction01）

package com.myservice.web;  import java.util.Map;  import com.opensymphony.xwork2.ActionContext; import com.opensymphony.xwork2.ActionSupport;  public class UserAction01 extends ActionSupport {   /**    *    */   private static final long serialVersionUID = 1L;   private User user;   private Map request;   private Map session;   private Map application;   public UserAction01(){     request = (Map)ActionContext.getContext().get("request");     session = ActionContext.getContext().getSession();     application = ActionContext.getContext().getApplication();   }     public String register(){     request.put("name", user.getName());     request.put("password", user.getPassword());     return SUCCESS;   }   public User getUser() {     return user;   }   public void setUser(User user) {     this.user = user;   }    }

这个方式是用ActionContext.getContext()方法获得context，然后得到request和session以及application

4、另外一种方式（UserAction02）非常常见，也是非常著名的方式-----Ioc（控制反转）和DI（依赖注入），它需要实现3个接口如下：

package com.myservice.web;  import java.util.Map;  import org.apache.struts2.interceptor.ApplicationAware; import org.apache.struts2.interceptor.RequestAware; import org.apache.struts2.interceptor.SessionAware;  import com.opensymphony.xwork2.ActionSupport;  public class UserAction02 extends ActionSupport implements RequestAware, SessionAware,ApplicationAware{   private Map<String, Object> request;   private Map<String, Object> session;   private Map<String, Object> application;   private User user;         public User getUser() {     return user;   }    public void setUser(User user) {     this.user = user;   }    public String register(){     request.put("name", user.getName());     request.put("password", user.getPassword());     return SUCCESS;   }      @Override   public void setApplication(Map<String, Object> application) {     // TODO Auto-generated method stub     this.application = application;   }    @Override   public void setSession(Map<String, Object> session) {     // TODO Auto-generated method stub     this.session = session;   }    @Override   public void setRequest(Map<String, Object> request) {     // TODO Auto-generated method stub     this.request = request;   }  }

这样就实现了一个功能--将user的名称和密码都放入request中，在使用时我们只需取出即可

5、success.jsp将request中内容取出并显示

<%@ page language="java" contentType="text/html; charset=UTF-8"   pageEncoding="UTF-8"%> <%@taglib uri="/struts-tags" prefix="s" %> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>Insert title here</title> </head> <body> <h3>成功注册</h3> <s:property value="#request.name"/>注册成功，密码为：<s:property value="#request.password"/> </body> </html>

其结果显示为：

//files.VeVB.COm/file_images/article/201606/201606130948442.jpg