Struts2学习笔记(7)-访问Web元素

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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：