拦截器，避免重复提交

一、如何分离字符串

使用StringTokenizer:

String flower = "水仙 玫瑰 百合";

         StringTokenizer tokenizer = new StringTokenizer(flower);

         while(tokenizer.hasMoreTokens()){

             System.out.println(tokenizer.nextToken());

         }//默认是以空格分割

//分割不考虑正则

String flower1 = "水仙*玫瑰*百合";

         StringTokenizer tokenizer1 = new StringTokenizer(flower1,"*");

         while(tokenizer1.hasMoreTokens()){

             System.out.println(tokenizer1.nextToken());

         }//使用*分割字符串

二、向存储范围中添加数据或访问数据

Action中的数据要显示在视图上，通常将数据保存到4个范围中，然后通过EL表达式显示；

Struts 2提供了一个：1——ActionContext的API，通过这个API的静态方法getContext( )可以向四个范围中添加数据。

                                2——ServletActionContext的API，通过这个API可以获取request，session，application，response对象； ServletActionContext直接得到原生的内置对象；

Action中访问或添加request，session，application属性：

/**

     * @功能：ActionContext应用

     */

    public String one(){

         //得到ActionContext对象

         ActionContext ac = ActionContext.getContext();

         //ActionContext也可以得到原生的request

         HttpServletRequest request = (HttpServletRequest) ac.get(ServletActionContext.HTTP_REQUEST);

         HttpServletResponse response = (HttpServletResponse) ac.get(ServletActionContext.HTTP_RESPONSE);

        System.out.println("sessionId==="+request.getSession().getId());

         //向request赛值

         ac.put("k.1", "石板桥上跑马------不留痕迹");

         //向session中赛值

         ac.getSession().put("k.2", "猴子吃大象------- 亏他张得开嘴");

         //向application中塞值

         ac.getApplication().put("k.3", "呆子不识走马灯 ------- 来的来，去的去");

        

         return "success";

    }

在Action中获取HttpServletRequest、HttpSession、ServletContext、HTTPServletResponse对象

/**

     * @功能：servletActionContext

     */

    public String two(){

         //ServletActionContext获取的示内置对象

         HttpServletRequest request = ServletActionContext.getRequest();

         ServletContext application = ServletActionContext.getServletContext();

         HttpSession session = ServletActionContext.getRequest().getSession();

         HttpServletResponse response = ServletActionContext.getResponse();

         //request

         request.setAttribute("k.1", "瞎子坐飞机----不知高低");

         //session

        //ServletActionContext.getRequest().getSession().setAttribute("k.2", "晚点的火车-------赶得上");

         session.setAttribute("k.2", "晚点的火车-------赶得上");

         //application

        //ServletActionContext.getServletContext().setAttribute("k.3","六月的山----清一色");

         application.setAttribute("k.3","六月的山----清一色");

         return "success";

    }

使用ServletActionContext向存储范围中添加获取数据，类要继承ServletRequestAware,ServletResponseAware,SessionAware,ApplicationAware接口，重写里面的方法

public class ClearAction implements ServletRequestAware,ServletResponseAware,SessionAware,ApplicationAware{

    //定义四个范围对象

    private HttpServletRequest request;

    private HttpServletResponse response;

    private Map<String, Object> sessionMap;

    private Map<String, Object> applicationMap;

   

    public String three(){

         request.setAttribute("k.1", "灯影子打店-----人旺财不旺");

         sessionMap.put("k.2", "猪苦胆泡黄连------苦上加苦");

         applicationMap.put("k.3", "孙悟空听见紧箍咒------头痛");

         return "success";

    }

    @Override

    public void setApplication(Map<String, Object> arg0) {

         this.applicationMap=arg0;

    }

    @Override

    public void setSession(Map<String, Object> arg0) {

         this.sessionMap=arg0;

    }

    @Override

    public void setServletResponse(HttpServletResponse arg0) {

         this.response=arg0;

    }

    @Override

    public void setServletRequest(HttpServletRequest arg0) {

         this.request = arg0;

    }

}

三、拦截器

定义拦截器步骤：

     1：定义页面：xxx.jsp

     

<%@ page language="java" contentType="text/html; charset=UTF-8"

    pageEncoding="UTF-8"%>

    <%

    session.setAttribute("user", "您已登录");

     %>>

    <h1>您已登录</h1>

 

     

<%@ page language="java" contentType="text/html; charset=UTF-8"

    pageEncoding="UTF-8"%>

    <%

      session.invalidate();//销毁session

     %>

     <h2>您已退出</h2>

     2.定义拦截类

拦截器必须实现com.opensymphony.xwork2.interceptor接口，并实现接口中的 public String intercept(ActionInvocation invocation)方法，

方法参数invocation调用invoke( )方法，表示继续调用目标Action，方法的返回值是目标Action返回的视图；

/**

 * @功能：拦截器类

 */

public class LoginInteception implements Interceptor {

    @Override

    public void destroy() {

    }

    @Override

    public void init() {

      

    }

    @Override

    public String intercept(ActionInvocation invocation) throws Exception {

        if(ActionContext.getContext().getSession().get("user")!=null){

             //已经登录

             //执行下一个拦截器或返回指定action

             return invocation.invoke();

         }

         //没有授权，拦截器拦住

        ActionContext.getContext().getSession().put("message", "您没有登录，请先登录");

         return "login";

    }

}

    3.定义Action

public class UserAction extends ActionSupport {

    private String message;

    public String getMessage() {

         return message;

    }

    public void setMessage(String message) {

         this.message = message;

    }

    public String execute(){

         this.message="您已登录，有权操作";

         return "success";

    }

}

4.设置配置文件struts.xml

    

<!-- 配置拦截器 -->

    <package name="userpkg" extends="struts-default" namespace="/interceptor">

        <!-- 定义拦截器类 -->

         <interceptors>

             <interceptor name="quanxian" class="org.ycpower.inteceptor.LoginInteception"></interceptor>

         <!-- 定义拦截器栈 -->

             <interceptor-stack name="mystack">

                    <!--defaultStack是系统拦截器栈，定义在struts-default.xml,必须将系统的拦截器类定义在上面-->

                 <interceptor-ref name="defaultStack" />

                 <interceptor-ref name="timer" />

                  <!--必须把自己的拦截器定义在下面-->

                 <interceptor-ref name="quanxian" />

             </interceptor-stack>

         </interceptors>

          <!-- 整个包中所有的action都是用mystack拦截器栈  -->

         <default-interceptor-ref name="mystack"></default-interceptor-ref>

             <global-results>

                 <result name="login">/interceptor/main.jsp</result>

             </global-results>

         <action name="main" class="org.ycpower.actions.UserAction">

             <!-- 本action内应用拦截器 -->

             <interceptor-ref name="mystack" />

             <result>/interceptor/main.jsp</result>

         </action>

    </package>

四、避免重复提交表单

     1——Action类必须继承ActionSupport

public class RegisterAction extends ActionSupport implements ModelDriven<UserModel> {

    UserModel user = new UserModel();

    @Override

    public UserModel getModel() {

         return user;

    }

    public UserModel getUser() {

         return user;

    }

    public void setUser(UserModel user) {

         this.user = user;

    }

    public String execute(){

         System.out.println("注册。。。。。。。。。。。。");

         return "success";

    }

}

2.页面是用struts标签

<%@ page language="java" contentType="text/html; charset=UTF-8"

    pageEncoding="UTF-8"%>

<%@ taglib uri="/struts-tags" prefix="s"%>

<!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>Insert title here</title>

</head>

<body>

    <s:form action="suc.action" method="post">

         姓名：<input type="text" name="username"/>

         性别：<input type="radio" name="sex" value="男" />男

         <input type="radio" name="sex" value="女"/>女

         爱好：<input type="checkbox" name="hobby"/>打篮球

         <input type="checkbox" name="hobby"/>跳舞

         <input type="checkbox" name="hobby"/>唱歌

         籍贯：<select name="province">

               <option value="甘肃">甘肃省</option>

               <option value="甘肃">山西省</option>

               <option value="甘肃">湖南省</option>

               <option value="甘肃">浙江省</option>

         </select>

         <s:token />

         <s:submit value="注册" />

    </s:form>

</body>

</html>

3.配置struts.xml

<package name="regpkg" extends="struts-default">

         <!-- 配置拦截器 -->

         <interceptors>

             <!-- 配置拦截器栈 -->

             <interceptor-stack name="repeatstack" >

                 <interceptor-ref name="defaultStack" />

                 <interceptor-ref name="token" />

             </interceptor-stack>

         </interceptors>

         <!-- 解决表单提交重复 -->

         <action name="suc" class="org.ycpower.actions.RegisterAction">

             <interceptor-ref name="repeatstack" />

             <result name="invalid.token" type="redirect">/volide/register.jsp</result>

             <result>/volide/ok.jsp</result>

         </action>

    </package>