6、Struts2_访问Web元素(request session application等)
struts2后台的Action跟我们前台的页面来通讯的时候,由于它不能直接拿到request,session，servletContext，比如当我们有人登陆了，我们要在session中设一个值,表示它登陆了,如何把相关的数据设到session里面?同样如何设置request、servletContext等?response不用访问它，因为我们的结果是通过result返回的.
访问Web元素可以有四种方法，下面依次列出
index.jsp
<?xml version="1.0" encoding="GB18030" ?><%@ page language="java" contentType="text/html; charset=GB18030" pageEncoding="GB18030"%><% String context = request.getContextPath(); %><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=GB18030" /> <title>Insert title here</title> </head><body> <form name="f" action="" method="post"> 用户名：<input type="text" name="name"/> 密码：<input type="text" name="password"/> <br /> <input type="button" value="submit1" onclick="javascript:document.f.action='login/login1';document.f.submit();" /> <input type="button" value="submit2" onclick="javascript:document.f.action='login/login2';document.f.submit();" /> <input type="button" value="submit3" onclick="javascript:document.f.action='login/login3';document.f.submit();" /> <input type="button" value="submit4" onclick="javascript:document.f.action='login/login4';document.f.submit();" /> </form></body></html>
<?xml version="1.0" encoding="GB18030" ?><%@ page language="java" contentType="text/html; charset=GB18030" pageEncoding="GB18030"%> <%@taglib uri="/struts-tags" prefix="s" %><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=GB18030" /> <title>Insert title here</title> </head><body>User Login Success!<br /><s:property value="#request.r1"/> | <%=request.getAttribute("r1") %> <br /><s:property value="#session.s1"/> | <%=session.getAttribute("s1") %> <br /><s:property value="#application.a1"/> | <%=application.getAttribute("a1") %> <br /><s:property value="#attr.a1"/><br /><s:property value="#attr.s1"/><br /><s:property value="#attr.r1"/><br /><s:debug></s:debug><br /></body></html><?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="login" extends="struts-default" namespace="/login"> <action name="login*" name="code">import java.util.Map;import com.opensymphony.xwork2.ActionContext;import com.opensymphony.xwork2.ActionSupport;public class LoginAction1 extends ActionSupport {private Map request;private Map session;private Map application;public LoginAction1() {request = (Map)ActionContext.getContext().get("request");session = ActionContext.getContext().getSession();application = ActionContext.getContext().getApplication();}public String execute() {request.put("r1", "r1");session.put("s1", "s1");application.put("a1", "a1");return SUCCESS; }}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 LoginAction2 extends ActionSupport implements RequestAware,SessionAware, ApplicationAware {private Map<String, Object> request;private Map<String, Object> session;private Map<String, Object> application;//DI dependency injection//IoC inverse of controlpublic String execute() {request.put("r1", "r1");session.put("s1", "s1");application.put("a1", "a1");return SUCCESS; }@Overridepublic void setRequest(Map<String, Object> request) {this.request = request;}@Overridepublic void setSession(Map<String, Object> session) {this.session = session;}@Overridepublic void setApplication(Map<String, Object> application) {this.application = application;}} import javax.servlet.ServletContext;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpSession;import org.apache.struts2.ServletActionContext;import com.opensymphony.xwork2.ActionSupport;public class LoginAction3 extends ActionSupport {private HttpServletRequest request;private HttpSession session;private ServletContext application;public LoginAction3() {request = ServletActionContext.getRequest();session = request.getSession();application = session.getServletContext();}public String execute() {request.setAttribute("r1", "r1");session.setAttribute("s1", "s1");application.setAttribute("a1", "a1");return SUCCESS; }}import javax.servlet.ServletContext;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpSession;import org.apache.struts2.interceptor.ServletRequestAware;import com.opensymphony.xwork2.ActionSupport;public class LoginAction4 extends ActionSupport implements ServletRequestAware {private HttpServletRequest request;private HttpSession session;private ServletContext application;public String execute() {request.setAttribute("r1", "r1");session.setAttribute("s1", "s1");application.setAttribute("a1", "a1");return SUCCESS; }@Overridepublic void setServletRequest(HttpServletRequest request) {this.request = request;this.session = request.getSession();this.application = session.getServletContext();}}