所有的学习我们必须先搭建好Struts2的环境（1、导入对应的jar包，2、web.xml，3、struts.xml）
第一节：拦截器简介
（百度百科Struts2）
Struts2 拦截器是在访问某个Action 或Action 的某个方法，字段之前或之后实施拦截，并且Struts2 拦截器是可
插拔的，拦截器是ＡＯＰ的一种实现．
优点：通用功能的封装，提供了可重用性；
第二节：Struts2 预定义拦截器&拦截器栈
1 <?xml version="1.0" encoding="UTF-8" ?> 2 <!DOCTYPE struts PUBLIC 3 "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN" 4 "http://struts.apache.org/dtds/struts-2.0.dtd"> 5 6 <struts> 7 8 <package name="manage" namespace="/" extends="struts-default"> 9 10 <interceptors> 11 <interceptor name="myInterceptor" class="com.wishwzp.interceptor.MyInterceptor"></interceptor> 12 </interceptors> 13 14 <action name="hello" class="com.wishwzp.action.HelloAction"> 15 <result name="success">success.jsp</result> 16 17 <interceptor-ref name="myInterceptor"></interceptor-ref> 18 <interceptor-ref name="defaultStack"></interceptor-ref> 19 </action> 20 </package> 21 22 </struts>
1 package com.wishwzp.interceptor; 2 3 import com.opensymphony.xwork2.ActionInvocation; 4 import com.opensymphony.xwork2.interceptor.Interceptor; 5 6 public class MyInterceptor implements Interceptor{ 7 8 @Override 9 public void destroy() { 10 // TODO Auto-generated method stub 11 System.out.println("MyInterceptor销毁"); 12 } 13 14 @Override 15 public void init() { 16 // TODO Auto-generated method stub 17 System.out.println("MyInterceptor初始化"); 18 } 19 20 @Override 21 public String intercept(ActionInvocation invocation) throws Exception { 22 System.out.println("在Action执行之前"); 23 String result=invocation.invoke(); 24 System.out.println("result:"+result); 25 System.out.println("在Action执行之后"); 26 return result; 27 } 28 29 }
1 package com.wishwzp.action; 2 3 import com.opensymphony.xwork2.ActionSupport; 4 5 public class HelloAction extends ActionSupport{ 6 7 /** 8 * 9 */ 10 private static final long serialVersionUID = 1L; 11 12 private String name; 13 14 15 16 public String getName() { 17 return name; 18 } 19 20 public void setName(String name) { 21 this.name = name; 22 } 23 24 @Override 25 public String execute() throws Exception { 26 System.out.println("执行了HelloAction的默认方法"); 27 return SUCCESS; 28 } 29 30 31 }
1 <%@ page language="java" contentType="text/html; charset=UTF-8" 2 pageEncoding="UTF-8"%> 3 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 4 <html> 5 <head> 6 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 7 <title>Insert title here</title> 8 </head> 9 <body> 10 Name:${name } 11 </body> 12 </html>
url:http://localhost:8080/Struts2Chap03/hello?name=Struts2
我们需要注意的是在MyInterceptor.java中的：
String result=invocation.invoke();
第三节：自定义拦截器简单实例
我们在第二节中“MyInterceptor.java”中已经是自己定义的拦截器了
第四节：自定义拦截器-登录验证拦截器
struts.xml
1 <?xml version="1.0" encoding="UTF-8" ?> 2 <!DOCTYPE struts PUBLIC 3 "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN" 4 "http://struts.apache.org/dtds/struts-2.0.dtd"> 5 6 <struts> 7 8 <package name="manage" namespace="/" extends="struts-default"> 9 10 <interceptors> 11 <interceptor name="loginInterceptor" class="com.wishwzp.interceptor.LoginInterceptor"></interceptor> 12 </interceptors> 13 14 <action name="user" class="com.wishwzp.action.UserAction"> 15 <result name="success">success.jsp</result> 16 <result name="error">error.jsp</result> 17 <interceptor-ref name="defaultStack"></interceptor-ref> 18 </action> 19 20 <action name="gril" class="com.wishwzp.action.GrilAction"> 21 <result name="success">success.jsp</result> 22 <result name="error">error.jsp</result> 23 <interceptor-ref name="loginInterceptor"></interceptor-ref> 24 <interceptor-ref name="defaultStack"></interceptor-ref> 25 </action> 26 </package> 27 28 </struts>
User.java
1 package com.wishwzp.model; 2 3 public class User { 4 5 private String userName; 6 private String password; 7 8 public String getUserName() { 9 return userName; 10 } 11 public void setUserName(String userName) { 12 this.userName = userName; 13 } 14 public String getPassword() { 15 return password; 16 } 17 public void setPassword(String password) { 18 this.password = password; 19 } 20 }
UserService.java
1 package com.wishwzp.service; 2 3 import com.wishwzp.model.User; 4 5 public class UserService { 6 7 public boolean login(User user){ 8 if("wishwzp".equals(user.getUserName())&&"123".equals(user.getPassword())){ 9 return true; 10 }else{ 11 return false; 12 } 13 } 14 }
UserAction.java
1 package com.wishwzp.action; 2 3 import java.util.Map; 4 5 import com.wishwzp.model.User; 6 import com.wishwzp.service.UserService; 7 import com.opensymphony.xwork2.ActionContext; 8 import com.opensymphony.xwork2.ActionSupport; 9 10 public class UserAction extends ActionSupport{ 11 12 /** 13 * 14 */ 15 private static final long serialVersionUID = 1L; 16 17 private UserService userService=new UserService(); 18 private User user; 19 private String error; 20 21 public User getUser() { 22 return user; 23 } 24 25 public void setUser(User user) { 26 this.user = user; 27 } 28 29 public String getError() { 30 return error; 31 } 32 33 public void setError(String error) { 34 this.error = error; 35 } 36 37 @Override 38 public String execute() throws Exception { 39 if(userService.login(user)){ 40 ActionContext actionContext=ActionContext.getContext();//获取上下文，去获取actionContext 41 Map<String, Object> session=actionContext.getSession();//通过actionContext去获取session 42 session.put("currentUser", user);//将用户存放在session中，就是放到了currentUser 43 return SUCCESS;//返回到SUCCESS 44 }else{ 45 this.error="用户名或密码错误"; 46 return "error"; 47 } 48 } 49 50 51 }
GrilAction.java
1 package com.wishwzp.action; 2 3 import com.opensymphony.xwork2.ActionSupport; 4 5 public class GrilAction extends ActionSupport{ 6 7 /** 8 * 9 */ 10 private static final long serialVersionUID = 1L; 11 @Override 12 public String execute() throws Exception { 13 System.out.println("看美女"); 14 return SUCCESS; 15 } 16 17 18 }
LoginInterceptor.java
1 package com.wishwzp.interceptor; 2 3 import java.util.Map; 4 5 import javax.servlet.http.HttpServletRequest; 6 7 import org.apache.struts2.ServletActionContext; 8 9 import com.opensymphony.xwork2.ActionContext; 10 import com.opensymphony.xwork2.ActionInvocation; 11 import com.opensymphony.xwork2.interceptor.Interceptor; 12 13 public class LoginInterceptor implements Interceptor{ 14 15 @Override 16 public void destroy() { 17 // TODO Auto-generated method stub 18 System.out.println("LoginInterceptor销毁"); 19 } 20 21 @Override 22 public void init() { 23 // TODO Auto-generated method stub 24 System.out.println("LoginInterceptor初始化"); 25 } 26 27 @Override 28 public String intercept(ActionInvocation invocation) throws Exception { 29 System.out.println("在Action执行之前"); 30 ActionContext actionContext=invocation.getInvocationContext();//获取actionContext，这样就可以获取session了 31 Map<String, Object> session=actionContext.getSession();//获取session 32 Object currentUser=session.get("currentUser");//获取前面的的用户有没有 33 String result=null; 34 if(currentUser!=null){ 35 result=invocation.invoke();//不是空的话，说明已经登录过了 36 }else{//否则没有登录 37 //获取request 38 HttpServletRequest request=(HttpServletRequest)invocation.getInvocationContext().get(ServletActionContext.HTTP_REQUEST); 39 request.setAttribute("error", "请先登录！"); 40 result="error"; 41 } 42 System.out.println("result:"+result); 43 System.out.println("在Action执行之后"); 44 return result; 45 } 46 47 }
login.jsp
1 <%@ page language="java" contentType="text/html; charset=UTF-8" 2 pageEncoding="UTF-8"%> 3 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 4 <html> 5 <head> 6 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 7 <title>Insert title here</title> 8 </head> 9 <body> 10 <form action="user" method="post"> 11 用户名：<input type="text" name="user.userName"/> 12 密码：<input type="password" name="user.password"/> 13 <input type="submit" value="登录"/> 14 </form> 15 </body> 16 </html>
success.jsp
1 <%@ page language="java" contentType="text/html; charset=UTF-8" 2 pageEncoding="UTF-8"%> 3 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 4 <html> 5 <head> 6 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 7 <title>Insert title here</title> 8 </head> 9 <body> 10 当前用户：${currentUser.userName } 11 </body> 12 </html>
error.jsp
1 <%@ page language="java" contentType="text/html; charset=UTF-8" 2 pageEncoding="UTF-8"%> 3 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 4 <html> 5 <head> 6 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 7 <title>Insert title here</title> 8 </head> 9 <body> 10 错误信息：${error } <a href="login.jsp">登录</a> 11 </body> 12 </html>
url：http://localhost:8080/Struts2Chap03/login.jsp
url:http://localhost:8080/Struts2Chap03/gril
我们再上面的代码中优化一下strut.xml。
其他什么地方都不变
struts.xml
1 <?xml version="1.0" encoding="UTF-8" ?> 2 <!DOCTYPE struts PUBLIC 3 "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN" 4 "http://struts.apache.org/dtds/struts-2.0.dtd"> 5 6 <struts> 7 8 9 <package name="manage" namespace="/" extends="struts-default"> 10 11 <interceptors> 12 <!-- 配置loginInterceptor拦截器 --> 13 <interceptor name="loginInterceptor" class="com.wishwzp.interceptor.LoginInterceptor"></interceptor> 14 15 <!-- 拦截器栈 --> 16 <!-- 配置一个名为myStack的拦截器栈，里面有拦截器loginInterceptor和默认的拦截器 --> 17 <interceptor-stack name="myStack"> 18 <interceptor-ref name="loginInterceptor"></interceptor-ref> 19 <interceptor-ref name="defaultStack"></interceptor-ref> 20 </interceptor-stack> 21 </interceptors> 22 23 <!-- 配置使用自己配置的默认拦截器myStack --> 24 <default-interceptor-ref name="myStack"></default-interceptor-ref> 25 26 <!-- 使用全局错误信息，就不需要去一个个写error了 ，所有的action都会找到这个全局error的--> 27 <global-results> 28 <result name="error">error.jsp</result> 29 </global-results> 30 31 <action name="user" class="com.wishwzp.action.UserAction"> 32 <result name="success">success.jsp</result> 33 34 <!-- 这个默认拦截器栈这里必须有，不然的话这里的登录也被拦截掉了 --> 35 <interceptor-ref name="defaultStack"></interceptor-ref> 36 </action> 37 38 <action name="gril" class="com.wishwzp.action.GrilAction"> 39 <result name="success">success.jsp</result> 40 </action> 41 </package> 42 43 </struts>