struts2 访问web元素

Struts2中访问web元素的四种方式及前台jsp页面获取后台值的方式
四种方式：

1. 通过ActionContext来访问request,session,application对象
2. 通过实现RequestAware、SessionAware、ApplicationAware接口来访问request,session,application对象
3. 通过ServletActionContext来访问request,session,application对象
4. 通过实现ServletRequestAware接口来访问request,session,application对象

演示代码：

方式一：

/**
 * 通过ActionContext来访问request,session,application对象
 * @author 健
 */
public class UserAction1 extends ActionSupport{
	/**
	 * 序列化
	 */
	private static final long serialVersionUID = 1L;
	/**
	 * request
	 */
	private Map <String,Object>request;
	/**
	 * response
	 */
	private Map <String,Object>session;
	/**
	 * application
	 */
	private Map <String,Object>application;
	/**
	 * 添加用户 
	 * @return 用户是否添加成功
	 */
	@SuppressWarnings("unchecked")
	@Override
	public String execute(){
		System.out.println("通过ActionContext来访问request,session,application对象");
		// 初始化
		request = (Map<String,Object>)ActionContext.getContext().get("request");
		session = ActionContext.getContext().getSession();
		application = ActionContext.getContext().getApplication();
		// 赋值
		request.put("requestKey", "requestValue");
		session.put("sessionKey", "sessionValue");
		application.put("applicationKey", "applicationValue");
		return "success";
	}
}

方式二：

/**
 * 通过实现RequestAware、SessionAware、ApplicationAware接口来访问request,session,application对象
 * @author 健
 */
public class UserAction2 extends ActionSupport implements RequestAware,SessionAware,ApplicationAware{
	/**
	 * 序列化
	 */
	private static final long serialVersionUID = 1L;
	/**
	 * request
	 */
	private Map <String,Object>request;
	/**
	 * response
	 */
	private Map <String,Object>session;
	/**
	 * application
	 */
	private Map <String,Object>application;
	/**
	 * 控制器
	 */
	@SuppressWarnings("unchecked")
	@Override
	public String execute(){
		System.out.println("通过实现RequestAware、SessionAware、ApplicationAware接口来访问request,session,application对象");
		// 赋值
		request.put("requestKey", "requestValue");
		session.put("sessionKey", "sessionValue");
		application.put("applicationKey", "applicationValue");
		return "success";
	}
	/* 
	 * 实现RequestAware中的方法
	 */
	@Override
	public void setRequest(Map<String, Object> request) {
		this.request = request;
	}
	/* 
	 * 实现ApplicationAware中的方法
	 */
	@Override
	public void setApplication(Map<String, Object> application) {
		this.application = application;
	}
	/* 
	 * 实现SessionAware中的方法
	 */
	@Override
	public void setSession(Map<String, Object> session) {
		this.session = session;
	}
}

方式三：

+/**
 * 通过ServletActionContext来访问request,session,application对象
 * @author 健
 */
public class UserAction3 extends ActionSupport{
	/**
	 * 序列化
	 */
	private static final long serialVersionUID = 1L;
	/**
	 * request
	 */
	private HttpServletRequest request;
	/**
	 * response
	 */
	private HttpSession session;
	/**
	 * application
	 */
	private ServletContext application;
	/**
	 * 控制器
	 */
	@SuppressWarnings("unchecked")
	@Override
	public String execute(){
		System.out.println("通过ServletActionContext来访问request,session,application对象");
		// 初始化
		request = ServletActionContext.getRequest();
		session = request.getSession();
		application = session.getServletContext();
		// 赋值
		request.setAttribute("requestKey", "requestValue");
		session.setAttribute("sessionKey", "sessionValue");
		application.setAttribute("applicationKey", "applicationValue");
		return "success";
	}
}

方式四：

/**
 * 通过实现ServletRequestAware接口来访问request,session,application对象
 * @author 健
 */
public class UserAction4 extends ActionSupport implements ServletRequestAware{
	/**
	 * 序列化
	 */
	private static final long serialVersionUID = 1L;
	/**
	 * request
	 */
	private HttpServletRequest request;
	/**
	 * response
	 */
	private HttpSession session;
	/**
	 * application
	 */
	private ServletContext application;
	/**
	 * 控制器
	 */
	@SuppressWarnings("unchecked")
	@Override
	public String execute(){
		System.out.println("通过实现ServletRequestAware接口来访问request,session,application对象");
		// 赋值
		request.setAttribute("requestKey", "requestValue");
		session.setAttribute("sessionKey", "sessionValue");
		application.setAttribute("applicationKey", "applicationValue");
		return "success";
	}
	/* 
	 * 实现ServletRequestAware接口中的方法
	 */
	@Override
	public void setServletRequest(HttpServletRequest request) {
		this.request = request;
		this.session = request.getSession();
		this.application = session.getServletContext();
	}
}

上面的action配套的struts.xml及jsp页面
struts.xml

<struts>
	<!-- 配置开发模式：修改不用重启服务器 -->
	<constant name="struts.devMode" value="true"/>
    <package name="" namespace="/login" extends="struts-default">
        <action name="login*" class="com.wj.struts2.action.UserAction{1}">
        	<result name="success">/success.jsp</result>
        	<result name="failure">/failure.jsp</result>
        </action>
    </package>
</struts>

index.jsp

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@taglib uri="/struts-tags" prefix="s" %>
<%
	String path = request.getContextPath();
	String basePath = request.getScheme() + "://"
			+ request.getServerName() + ":" + request.getServerPort()
			+ path + "/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
	<head>
		<base href="<%=basePath%>">

		<title>Struts2_AccessWebElements</title>
		<meta http-equiv="pragma" content="no-cache">
		<meta http-equiv="cache-control" content="no-cache">
		<meta http-equiv="expires" content="0">
		<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
		<meta http-equiv="description" content="This is my page">
		<!--
		<link rel="stylesheet" type="text/css" href="styles.css" mce_href="styles.css">
		-->
		<mce:script language="javascript"><!--
			function sub(str){
				document.form1.action = str;
				document.form1.submit();
			}
		
// --></mce:script>
	</head>

	<body>
		<form name="form1">
			<div>
				Struts2中访问web元素的四种方式<br>
				方式一：<input type="button" value="submit1" onclick="sub('<%=basePath%>login/login1')"><br>	
				方式二：<input type="button" value="submit2" onclick="sub('<%=basePath%>login/login2')"><br>
				方式三：<input type="button" value="submit3" onclick="sub('<%=basePath%>login/login3')"><br>
				方式四：<input type="button" value="submit4" onclick="sub('<%=basePath%>login/login4')"><br>
			</div>
		</form>
	</body>
</html>

success.jsp

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@taglib uri="/struts-tags" prefix="s" %>
<%
	String path = request.getContextPath();
	String basePath = request.getScheme() + "://"
			+ request.getServerName() + ":" + request.getServerPort()
			+ path + "/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
	<head>
		<base href="<%=basePath%>">
		<title>Struts2_AccessWebElements</title>
		<meta http-equiv="pragma" content="no-cache">
		<meta http-equiv="cache-control" content="no-cache">
		<meta http-equiv="expires" content="0">
		<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
		<meta http-equiv="description" content="This is my page">
		<!--
		<link rel="stylesheet" type="text/css" href="styles.css" mce_href="styles.css">
		-->
	</head>

	<body>
		requestKey---<s:property value="#request.requestKey"/>|<%=request.getAttribute("requestKey")%><br>
		sessionKey---<s:property value="#session.sessionKey"/>|<%=session.getAttribute("sessionKey")%><br>
		applicationKey---<s:property value="#application.applicationKey"/>|<%=application.getAttribute("applicationKey")%><br>
		--------------------------------------------
		<s:debug></s:debug>
	</body>
</html>

前台jsp页面获取后台值的方式

<s:property value="#request.requestKey"/>|<%=request.getAttribute("requestKey")%>

<s:property value="#session.sessionKey"/>|<%=session.getAttribute("sessionKey")%>

<s:property value="#application.applicationKey"/>|<%=application.getAttribute("applicationKey")%>

参考链接：

http://blog.csdn.net/zsm653983/article/details/8039292