struts2 攔截器使用例子

時間 2019-11-24

原文原文鏈接

今天剛學了用struts2的攔截器,就用他作了個權限控制的小例子來加深對攔截器的認識.用戶經合法途徑登錄後用戶登錄信息會保存在session中,用戶在訪問其餘資源時,攔截器會首先查看session中是否有用戶信息.從而控制用戶登錄javascript

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%@ taglib prefix="s" uri="/struts-tags" %>java

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
</head>
<body>
    <s:form name="form1" action="login">
    <s:textfield name="username" label="username"></s:textfield>
    <s:password name="password" label="password"></s:password>
    <s:submit value="submit"/>
    </s:form>
</body>
</html>
web

package com.huan.tv.web;apache

import com.huan.tv.domain.User;
import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionSupport;session

public class LoginAction extends ActionSupport {app

private static final long serialVersionUID = 7016663291573110941L;
private String username;
private String password;

@Override
public String execute() throws Exception {
  if("java".equals(username.trim())&&"123".equals(password.trim())){
   User user = new User(username,password);
   ActionContext.getContext().getSession().put("user", user);
  }
  return SUCCESS;
}

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;
}

}
Uer.java類封裝了用戶登錄的信息dom

package com.huan.tv.domain;jsp

public class User {ide

private String username;
private String password;
public User() {
  super();
}
public User(String username, String password) {
  super();
  this.username = username;
  this.password = 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;
}

}
下面就是關鍵的攔截器了

package com.huan.tv.web;

import javax.servlet.http.HttpServletResponse;

import org.apache.struts2.ServletActionContext;

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

public class AuthorInterceptor extends AbstractInterceptor {

private static final long serialVersionUID = 5359767511938232965L;

public String intercept(ActionInvocation invocation) throws Exception {
  ActionContext ac = ActionContext.getContext();
  Object user = ac.getSession().get("user");
  if (user != null) {
   return invocation.invoke();
  } else {
   HttpServletResponse response = ServletActionContext.getResponse();
   response.setContentType("text/html;charset=UTF-8");
   response.getWriter().write(
     "<script language=\"javascript\">alert('請登陸系統！');parent.location.href='"
       + ServletActionContext.getRequest()
         .getContextPath() + "/login.jsp';</script>");
  }
  return null;

}

}
攔截器就是經過判斷session裏user是否有值,user爲空說明用戶沒有登錄就返回首頁.登錄後就invocation.invoke();將控制權轉交給Action的execute方法

配置文件struts.xml

<?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>
<package name="base-package" extends="struts-default">
  <interceptors>
   <interceptor name="author"
    class="com.huan.tv.web.AuthorInterceptor" />
   <interceptor-stack name="permissionStack">
    <interceptor-ref name="defaultStack" />
    <interceptor-ref name="author" />
   </interceptor-stack>
  </interceptors>

  <action name="login" class="com.huan.tv.web.LoginAction">
  <result>/welcome.jsp</result>
  </action>
  <action name="view" class="com.huan.tv.web.ViewAction">
  <result>/index.jsp</result>
  <interceptor-ref name="permissionStack"/>
  </action>
</package>
</struts>

咱們定義了一個攔截器棧,它包含剛寫了權限攔截器和默認攔截器.login是登錄的不用權限控制.view是登錄後查看的須要加上攔截器.若是用戶不登錄直接訪問view.action則系統攔截器就會起做用,提示用戶登錄後才能操做.

welcome.jsp登錄後的歡迎頁

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@ taglib prefix="s" uri="/struts-tags" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
</head>

<body>
    登錄成功! <br>
    <s:form action="view">
    <s:submit value="submit"/>
    </s:form>
</body>
</html>
index.jsp

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
</head>

<body>
通過view.action後訪問的 <br>
</body>
</html>
最後別忘了web.xml中添加struts2

<filter> <filter-name>Struts2</filter-name> <filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class> </filter> <filter-mapping> <filter-name>Struts2</filter-name> <url-pattern>*.action</url-pattern> </filter-mapping> <filter-mapping> <filter-name>Struts2</filter-name> <url-pattern>*.jsp</url-pattern> </filter-mapping>

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