Struts2学习之拦截器栈

拦截器栈：

　　- 从结构上看：拦截器栈相当于多个拦截器的组合

　　- 从功能上看：拦截器栈也是拦截器

默认拦截器栈：

　　- 在struts-core.jar中的struts-default.xml中自定义了一个default拦截器栈，并且将其指定为默认拦截器栈

　　- 只要定义包的过程中继承struts-default包，那么默认defaultStack将是默认的拦截器

　　- 当为包中的某个action显示指定了某个拦截器，那么默认的拦截器将不会生效

　　- 拦截器栈中的各个拦截器的顺序很重要（一般讲默认拦截器器栈放在前面）

实例:

1.项目结构

2.pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
  
  	<modelVersion>4.0.0</modelVersion>
  	
	<groupId>org.struts</groupId>
	<artifactId>Struts2-AuthInterceptor</artifactId>
	<packaging>war</packaging>
	<version>0.0.1-SNAPSHOT</version>
	
	<properties>
		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
		<struts.version>2.5.10</struts.version>
	</properties>
	
	<dependencies>
		<!-- Junit -->
		<dependency>
			<groupId>junit</groupId>
			<artifactId>junit</artifactId>
			<version>4.12</version>
			<scope>test</scope>
		</dependency>
		<!-- Struts2 -->
		<dependency>
		    <groupId>org.apache.struts</groupId>
		    <artifactId>struts2-core</artifactId>
		    <version>${struts.version}</version>
		</dependency>
	</dependencies>
	
	<build>
		<finalName>Struts2-AuthInterceptor</finalName>
	</build>
  
</project>

3.web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://java.sun.com/xml/ns/javaee"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
                      http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
  version="3.0" metadata-complete="true">

	<!-- 首页 -->
	<welcome-file-list>
		<welcome-file>login.jsp</welcome-file>
	</welcome-file-list>
	
	<!-- Struts2过滤器 -->
	<filter>
		<filter-name>struts2</filter-name>
		<filter-class>org.apache.struts2.dispatcher.filter.StrutsPrepareAndExecuteFilter</filter-class>
	</filter>
	<filter-mapping>
		<filter-name>struts2</filter-name>
		<url-pattern>/*</url-pattern>
	</filter-mapping>

</web-app>

4.login.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!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>用户登录</title>
</head>
<body>
	<form action="login" method="post">
		<font color="red">${loginError }</font><br/>
		用户名：<input type="text" name="username"/><br/>
		密   码：<input type="password" name="password"/><br/>
		<input type="submit" value="登录"/>
		<input type="reset" value="重置"/>
	</form>
</body>
</html>

5.manager.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!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>管理界面</title>
</head>
<body>
	欢迎进入管理页面，该页面只有登录用户才能访问！
</body>
</html>

6.LoginAction.java

package org.struts.action;

import java.util.Map;

import org.apache.struts2.interceptor.SessionAware;

import com.opensymphony.xwork2.ActionSupport;

public class LoginAction extends ActionSupport implements SessionAware {

	private static final long serialVersionUID = 1L;
	
	private String username;// 用户名
	private String password;// 密码
	private Map<String, Object> session;// Session
	
	
	@Override
	public String execute() throws Exception {
		
		if ("admin".equals(username) && "123456".equals(password)) {
			session.put("userInfo", username);
			session.remove("loginError");
			return SUCCESS;
		} else {
			session.put("loginError", "用户名或密码错误");
			session.remove("userInfo");
			return "login";
		}
		
	}

	public void setSession(Map<String, Object> session) {
		
		this.session = session;
		
	}

	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;
	}

}

7.AuthInterceptor.java

package org.struts.interceptor;

import java.util.Map;

import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.interceptor.AbstractInterceptor;

public class AuthInterceptor extends AbstractInterceptor {

	private static final long serialVersionUID = 1L;

	@Override
	public String intercept(ActionInvocation invocation) throws Exception {
		
		// 获取session
		ActionContext context = ActionContext.getContext();
		Map<String, Object> session = context.getSession();
		if (session.get("userInfo") != null) { // 登录成功
			String result = invocation.invoke();
			return result;
		} else {// 未登录
			session.put("loginError", "请先登录");
			return "login";
		}
		
	}

}

8.struts.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE struts PUBLIC
    "-//Apache Software Foundation//DTD Struts Configuration 2.5//EN"
    "http://struts.apache.org/dtds/struts-2.5.dtd">
<struts>

	<package name="default" extends="struts-default" namespace="/">
	
		<!-- 注册拦截器 -->
		<interceptors>
			<interceptor name="auth" class="org.struts.interceptor.AuthInterceptor"/>
			<interceptor-stack name="authStack">
				<interceptor-ref name="defaultStack"/>
				<interceptor-ref name="auth"/>
			</interceptor-stack>
		</interceptors>
	
		<!-- 通过此Action访问后台管理页面 -->
		<action name="auth">
			<result>/WEB-INF/view/manager.jsp</result>
			<result name="login">/login.jsp</result>
			<interceptor-ref name="authStack"/>
		</action>
	
		<action name="login" class="org.struts.action.LoginAction">
			<result>/WEB-INF/view/manager.jsp</result>
			<result name="login">/login.jsp</result>
		</action>
	</package>

</struts>

9.结果预览

　　9.1 未登录直接访问

　　9.2 登录成功

　　9.3 登录成功后访问

参考：http://www.imooc.com/video/9102