7.11--SSH学习之Struts拦截器

本文主要是介绍7.11--SSH学习之Struts拦截器，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

拦截器：

1. 访问Action的时候才能启动拦截器，访问其他资源不行
2. 在Action访问过程中，必须使用拦截器
3. 拦截器分为系统拦截器和用户自定义拦截器
   
   
   

访问ServletAPI：

1. 解耦合的方式访问ServletAP（2种）
2. 耦合的方式访问ServletAP（2种）
   
   
   

示例解耦合:

1. 解耦合一，Action继承ActionSupport

public class FirstAction extends ActionSupport {private Map<String,Object> request;private Map<String,Object> session;private Map<String,Object> application;public String execute() throws Exception{System.out.println("in FirstAction method execute()");ActionContext ac = ActionContext.getContext(); request = (Map<String,Object>)ac.get("request");request.put("one","11");session = ac.getSession();session.put("two", "小青");application = ac.getApplication();application.put("three", "老大");return "success";}}

2. 解耦合二,Action继承ActionSupport并实现RequestAware,SessionAware，ApplicationAware

public class SecondAction extends ActionSupport implements RequestAware,SessionAware,ApplicationAware{private Map<String,Object> request;private Map<String,Object> session;private Map<String,Object> application;@Overridepublic void setApplication(Map<String, Object> application) {// TODO Auto-generated method stubthis.application=application;}@Overridepublic void setSession(Map<String, Object> session) {// TODO Auto-generated method stubthis.session=session;}@Overridepublic void setRequest(Map<String, Object> request) {// TODO Auto-generated method stubthis.request=request;}//解耦合的方式public String execute() throws Exception{System.out.println("in SecondAction method execute()");request.put("one", "苹果");session.put("two", "橘子");application.put("three", "西瓜");return "success";}}

示例耦合:

1. 耦合一，Action继承ActionSupport

public class ThreeAction extends ActionSupport {private HttpServletRequest request;private HttpSession session;private ServletContext application;public String execute() throws Exception{System.out.println("in ThreeAction method: execute()");request = ServletActionContext.getRequest();String userName = request.getParameter("userName");System.out.println(userName);request.setAttribute("one", userName);session = request.getSession();session.setAttribute("two", "雪碧");application = ServletActionContext.getServletContext();application.setAttribute("three", "可乐");return "success";}}

2. 耦合二，Action继承ActionSupport,并实现ServletRequestAware,ServletContextAware

public class FourAction extends ActionSupport implements ServletRequestAware,ServletContextAware {private HttpServletRequest request;private HttpSession session;private ServletContext application;@Overridepublic void setServletContext(ServletContext application) {// TODO Auto-generated method stubthis.application=application;}@Overridepublic void setServletRequest(HttpServletRequest request) {// TODO Auto-generated method stubthis.request=request;}public String execute() throws Exception{System.out.println("in ThreeAction method: execute()");request.setAttribute("one", "红酒");session = request.getSession();session.setAttribute("two", "白酒");application.setAttribute("three", "黄酒");return "success";}
}

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学习拦截器和访问ServletAPI后，做了一个demo
描述：
1. 管理员登录系统可以查看机密信息
2. 查看机密信息必须先登录
3. 普通用户不能进入系统
4. 黑名单中的人不能进入系统

管理员：susu
黑名单：Tom
普通用户：初susu之外的用户

示例代码：

1. UserLoginAction用来检测是否为管理员

**UserLoginAction.java**
public class UserLoginAction extends ActionSupport {private String userName;private String userPwd;public String getUserName() {return userName;}public void setUserName(String userName) {this.userName = userName;}public String getUserPwd() {return userPwd;}public void setUserPwd(String userPwd) {this.userPwd = userPwd;}public String execute() throws Exception{System.out.println("in execute()!!!");String flag = "input";if(userName.equals("susu")&&userPwd.equals("1111")){ActionContext.getContext().getSession().put("userName", userName);flag = "success";}else{ActionContext.getContext().getSession().put("message", "用户名或密码错误！");}return flag;}public String checkInter() throws Exception{System.out.println("in checkInter()");return "success";}
}

2. BlackListInterceptor黑名单拦截器，拦截黑名单中的人进入系统

**BlackListInterceptor.java**
public class BlackListInterceptor extends AbstractInterceptor {private HttpServletRequest request;@Overridepublic String intercept(ActionInvocation invo) throws Exception {// TODO Auto-generated method stubSystem.out.println("in BlackListInterceptor");request = ServletActionContext.getRequest();String strName = request.getParameter("userName");if(strName.equals("Tom")){return "error";}else{return invo.invoke();}}}

3. CheckSecretInterceptor机密信息拦截器，判断登录用户是否为管理员

**CheckSecretInterceptor.java**
public class CheckSecretInterceptor extends AbstractInterceptor {@Overridepublic String intercept(ActionInvocation acvo) throws Exception {// TODO Auto-generated method stubSystem.out.println("拦截器开始执行");Object obj = ActionContext.getContext().getSession().get("userName");String strName = obj != null ?obj.toString():"";if(strName.equals("susu")){String result = acvo.invoke();System.out.println("拦截器结束执行");return result;}else{System.out.println("拦截器结束执行");ActionContext.getContext().getSession().put("message", "还未登录，不能访问机密信息");return "input";}}
}

4. struts.xml中的配置

        <interceptors><interceptor name="checklogin" class="com.su.web.interceptor.CheckSecretInterceptor"></interceptor><interceptor name="errorInter" class="com.su.web.interceptor.BlackListInterceptor"></interceptor></interceptors><!-- *************黑名单拒绝进入，只有特定用户才能查看机密信息************** --><action name="login" class="com.su.web.action.UserLoginAction"><interceptor-ref name="defaultStack"></interceptor-ref><interceptor-ref name="errorInter"></interceptor-ref><result type="dispatcher" name="input">/login.jsp</result><result type="dispatcher" name="success">/success.jsp</result><result type="redirect" name="error">/errorname.jsp</result></action><action name="secret" class="com.su.web.action.UserLoginAction" method="checkInter"><interceptor-ref name="checklogin"></interceptor-ref><!-- defaultStack把表单元素提交到get，set,方法 --><interceptor-ref name="defaultStack"></interceptor-ref><result type="dispatcher" name="success">/secret.jsp</result><result type="dispatcher" name="input">/login.jsp</result></action><!-- **************************************************************--><!-- 先执行拦截器，在拦截器中再判断是否需要执行action中的方法，最后根据返回结果，跳转指定页面 -->

5. 登录界面，填写登录信息，用户名和密码login.jsp

<body><form action="login" method="post">用户名：<input type="text" name="userName"><br>密码：<input type="password" name="userPwd"><br><span style="color: red">${message }</span><input type="submit" value="提交"></form></body>

6. 登陆成功页面显示管理员姓名和机密信息超链接success.jsp

 <body>  User:${userName}<br>You are successful! <br>So,you can look <a href="secret.action">The Sercet Message</a></body>

7. 机密信息页面secret.jsp

<body>This is a secret Page! <br>But,you must keep secret!!!</body>

8. `黑名单中的人登陆，显示的页面errorname.jsp

 <body>Sorry！you are in the BlackList!</body>

运行结果：

1. 管理员登录：
   
   
   
   
2. 管理员登录成功：
   
   
   
   
3. 管理员查看机密信息
   
   
   
   
4. 非管理员登陆，提示错误信息
   
   
   
   
5. 黑名单中的人登录，显示errorname.jsp页面
   
   
   
   

到此完结！O(∩_∩)O谢谢

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Author：su1573

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