strtus2 web资源获取

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拦截器获取web资源模式

方式一：使用ServletRequestAware拦截器

FirstAction.java

<span style="font-size:18px;"><span style="font-size:18px;">package action;import javax.servlet.ServletContext;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import org.apache.struts2.interceptor.ServletRequestAware;import org.apache.struts2.interceptor.ServletResponseAware;import org.apache.struts2.util.ServletContextAware;import com.opensymphony.xwork2.ActionSupport;public class FirstAction extends ActionSupport implements ServletRequestAware,ServletResponseAware,ServletContextAware{private HttpServletRequest request;private HttpServletResponse response;private ServletContext context;@Overridepublic String execute() throws Exception {String username=this.request.getParameter("username");String password=this.request.getParameter("password");System.out.println(username+password);return "success";}@Overridepublic void setServletContext(ServletContext arg0) {this.context=arg0;}@Overridepublic void setServletResponse(HttpServletResponse arg0) {this.response=arg0;}@Overridepublic void setServletRequest(HttpServletRequest arg0) {this.request=arg0;}}</span></span>

struts.xml

<span style="font-size:18px;"><span style="font-size:18px;"><?xml version="1.0" encoding="UTF-8" ?><!DOCTYPE struts PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 2.1//EN" "http://struts.apache.org/dtds/struts-2.1.dtd"><struts><package name="action" extends="struts-default"><action name="firstAction" class="action.FirstAction"><result name="success">/index.jsp</result></action></package></struts>    </span></span>

index.jsp

<span style="font-size:18px;"><span style="font-size:18px;"><%@ page language="java" import="java.util.*" pageEncoding="ISO-8859-1"%><%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>My JSP 'index.jsp' starting page</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">-->  </head>    <body>  <form action="<%=path%>/firstAction.action" method="post">      username: <input type="text" name="username">      password: <input type="password" name="password">      <button type="submit">submit</button>  </form>  </body></html></span></span>

方式二：使用RequestAware拦截器

SecondAction.java

<span style="font-size:18px;"><span style="font-size:18px;">package action;import java.util.Map;import javax.servlet.ServletContext;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import org.apache.struts2.StrutsStatics;import org.apache.struts2.interceptor.RequestAware;import com.opensymphony.xwork2.ActionSupport;public class SecondAction extends ActionSupport implements RequestAware {private HttpServletRequest request;private HttpServletResponse response;private ServletContext context;@Overridepublic void setRequest(Map<String, Object> arg0) {request=(HttpServletRequest)arg0.get(StrutsStatics.HTTP_REQUEST);response=(HttpServletResponse)arg0.get(StrutsStatics.HTTP_RESPONSE);context=(ServletContext)arg0.get(StrutsStatics.SERVLET_CONTEXT);}@Overridepublic String execute() throws Exception {String username=request.getParameter("username");String password=request.getParameter("password");System.out.println(username+password);return "success";}}</span></span>

静态对象获取web资源模式

使用Struts2内置静态对象ActionContext

ThirdAction.java

<span style="font-size:18px;">package action;import javax.servlet.ServletContext;import javax.servlet.ServletRequest;import javax.servlet.ServletResponse;import org.apache.struts2.ServletActionContext;import com.opensymphony.xwork2.ActionContext;import com.opensymphony.xwork2.ActionSupport;public class ThirdAction extends ActionSupport {@Overridepublic String execute() throws Exception {ActionContext context=ActionContext.getContext();ServletRequest request=(ServletRequest) context.get(ServletActionContext.HTTP_REQUEST);ServletResponse response=(ServletResponse) context.get(ServletActionContext.HTTP_RESPONSE);ServletContext servletContext=(ServletContext) context.get(ServletActionContext.SERVLET_CONTEXT);System.out.println(request.getParameter("username")+request.getParameter("password"));return "success";}}</span>

使用Struts2内置静态对象ServletActionContext

<span style="font-size:18px;">package action;import javax.servlet.ServletContext;import javax.servlet.ServletRequest;import javax.servlet.ServletResponse;import org.apache.struts2.ServletActionContext;import com.opensymphony.xwork2.ActionSupport;public class FourthAction extends ActionSupport {@Overridepublic String execute() throws Exception {// TODO Auto-generated method stubServletRequest request=ServletActionContext.getRequest();ServletResponse response=ServletActionContext.getResponse();ServletContext context=ServletActionContext.getServletContext();System.out.println(request.getParameter("username")+request.getParameter("password"));return "success";}}</span>

登陆实例

LoginAction.java

package action;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpSession;import org.apache.struts2.ServletActionContext;import bean.User;import com.opensymphony.xwork2.ActionSupport;public class LoginAction extends ActionSupport {private String username;private String password;public String getUsername() {return username;}public void setUsername(String username) {this.username = username;}public String getPassword() {return password;}public void setPassword(String password) {this.password = password;}@Overridepublic String execute() throws Exception {if(username.equals("admin")&&password.equals("helloworld")){User user=new User();user.setUsername(username);user.setPassword(password);HttpServletRequest request=ServletActionContext.getRequest();HttpSession session=request.getSession();session.setAttribute("user", user);return "success";}else{return "failed";}}}

success.jsp

<%@ page language="java" import="java.util.*" pageEncoding="ISO-8859-1"%><%@ page import="bean.User" %><%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%>">          </head>    <body>    <% User user=(User)session.getAttribute("user"); %>    welcome: <%=user.getUsername() %>!      </body></html>

struts.xml

<?xml version="1.0" encoding="UTF-8" ?><!DOCTYPE struts PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 2.1//EN" "http://struts.apache.org/dtds/struts-2.1.dtd"><struts><package name="action" extends="struts-default"><action name="loginAction" class="action.LoginAction"><result name="success">/success.jsp</result><result name="failed">/index.jsp</result></action></package></struts>

application ServletContext 服务器对象只要服务器不关闭则该对象始终存在

存储在服务器内存中的对象，因此一般的对象不能保存在服务器中，因为容易导致服务器内存溢出而宕机

具体的使用场景可以是：驾校的考试系统，只需要注册用户就可以免费使用，用户量庞大

每次只出现一个题，然后做完本道题，自动跳转到下一个道题

实际的原理是：程序启动时，立即从数据库中取出需要获取的内容，放置到服务器application对象中，

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