（九）Struts2 防重复提交

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：重复提交示例演示

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="manager" extends="struts-default">

         <action name="student" class="com.wishwzp.action.StudentAction" method="add">

             <result name="success">/success.jsp</result>

         </action>

     </package>

 </struts>

Student.java

 package com.wishwzp.model;

 public class Student {

     private String name;

     private String age;

     public String getName() {

         return name;

     }

     public void setName(String name) {

         this.name = name;

     }

     public String getAge() {

         return age;

     }

     public void setAge(String age) {

         this.age = age;

     }

     @Override

     public String toString() {

         return "Student [name=" + name + ", age=" + age + "]";

     }

 }

StudentAction.java

 package com.wishwzp.action;

 import com.wishwzp.model.Student;

 import com.opensymphony.xwork2.ActionSupport;

 public class StudentAction extends ActionSupport{

     /**

      *

      */

     private static final long serialVersionUID = 1L;

     private Student student;

     public Student getStudent() {

         return student;

     }

     public void setStudent(Student student) {

         this.student = student;

     }

     public String add() throws Exception {

         System.out.println("开始添加学生："+student);

         Thread.sleep(5000);

         System.out.println(student.getName()+"添加完成");

         return SUCCESS;

     }

 }

student.jsp

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

     pageEncoding="UTF-8"%>

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

 <!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>

 <form action="student" method="post" >

     姓名：<input type="text" name="student.name"/><br/>

     年龄：<input type="text" name="student.age"/><br/>

     <input type="submit" value="提交"/>

 </form>

 </body>

 </html>

success.jsp

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

     pageEncoding="UTF-8"%>

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

 <!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>

 学生添加成功！

 </body>

 </html>

结果显示：

如果我们反复的提交的话，后台就会反复提交很多次的数据，而这些数据都会提交到后台的，我们现在要避免这样的情况发生。

这样我们第二节就可以防这样的重复提交

第二节：使用<s:token/>标签防重复提交

<s:token></s:token> ：加在form 里；

使用token 拦截器：

在struts.xml必须配置

<interceptor-ref name="token"></interceptor-ref>

<interceptor-ref name="defaultStack"></interceptor-ref>

<result name="invalid.token">/student.jsp</result> ：在struts.xml 里配置，假如出现重复提交，则直接回到页面；

<s:actionerror/>：在页面上显示错误信息；

例子：

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="manager" extends="struts-default">

         <action name="student" class="com.wishwzp.action.StudentAction" method="add">

             <result name="success">/success.jsp</result>

             <!-- 在struts.xml 里配置，假如出现重复提交，则直接回到页面 -->

             <result name="invalid.token">/student.jsp</result>

             <!-- 使用token 拦截器 -->

             <interceptor-ref name="token"></interceptor-ref>

             <interceptor-ref name="defaultStack"></interceptor-ref>

         </action>

     </package>

 </struts>

Student.java

 package com.wishwzp.model;

 public class Student {

     private String name;

     private String age;

     public String getName() {

         return name;

     }

     public void setName(String name) {

         this.name = name;

     }

     public String getAge() {

         return age;

     }

     public void setAge(String age) {

         this.age = age;

     }

     @Override

     public String toString() {

         return "Student [name=" + name + ", age=" + age + "]";

     }

 }

StudentAction.java

 package com.wishwzp.action;

 import com.wishwzp.model.Student;

 import com.opensymphony.xwork2.ActionSupport;

 public class StudentAction extends ActionSupport{

     /**

      *

      */

     private static final long serialVersionUID = 1L;

     private Student student;

     public Student getStudent() {

         return student;

     }

     public void setStudent(Student student) {

         this.student = student;

     }

     public String add() throws Exception {

         System.out.println("开始添加学生："+student);

         Thread.sleep(5000);

         System.out.println(student.getName()+"添加完成");

         return SUCCESS;

     }

 }

student.jsp

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

     pageEncoding="UTF-8"%>

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

 <!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:actionerror/>

 <form action="student" method="post" >

     <s:token></s:token>

     姓名：<input type="text" name="student.name"/><br/>

     年龄：<input type="text" name="student.age"/><br/>

     <input type="submit" value="提交"/>

 </form>

 </body>

 </html>

success.jsp

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

     pageEncoding="UTF-8"%>

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

 <!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>

 学生添加成功！

 </body>

 </html>

结果显示：

这样使用防重复提交拦截器，我们不管在前端页面按多少次提交，后天数据就一个数据，不会出现像上面很多次的数据了。

不过这样的我们可以看到这样的错误信号，我们可不可以直接无视这样的防重复提交呢！这里我们第三节就讲的这个。

第三节：使用tokenSession 拦截器防重复提交

tokenSesssion 拦截器直接无视重复提交的请求；

<interceptor-ref name="tokenSession"></interceptor-ref>

<interceptor-ref name="defaultStack"></interceptor-ref>

例子：

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="manager" extends="struts-default">    

         <action name="student" class="com.wishwzp.action.StudentAction" method="add">

             <result name="success">/success.jsp</result>

             <interceptor-ref name="tokenSession"></interceptor-ref>

             <interceptor-ref name="defaultStack"></interceptor-ref>

         </action>

     </package>

 </struts>

Student.java

 package com.wishwzp.model;

 public class Student {

     private String name;

     private String age;

     public String getName() {

         return name;

     }

     public void setName(String name) {

         this.name = name;

     }

     public String getAge() {

         return age;

     }

     public void setAge(String age) {

         this.age = age;

     }

     @Override

     public String toString() {

         return "Student [name=" + name + ", age=" + age + "]";

     }

 }

StudentAction.java

 package com.wishwzp.action;

 import com.wishwzp.model.Student;

 import com.opensymphony.xwork2.ActionSupport;

 public class StudentAction extends ActionSupport{

     /**

      *

      */

     private static final long serialVersionUID = 1L;

     private Student student;

     public Student getStudent() {

         return student;

     }

     public void setStudent(Student student) {

         this.student = student;

     }

     public String add() throws Exception {

         System.out.println("开始添加学生："+student);

         Thread.sleep(5000);

         System.out.println(student.getName()+"添加完成");

         return SUCCESS;

     }

 }

student.jsp

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

     pageEncoding="UTF-8"%>

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

 <!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:actionerror/>

 <form action="student" method="post" >

     <s:token></s:token>

     姓名：<input type="text" name="student.name"/><br/>

     年龄：<input type="text" name="student.age"/><br/>

     <input type="submit" value="提交"/>

 </form>

 </body>

 </html>

success.jsp

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

     pageEncoding="UTF-8"%>

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

 <!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>

 学生添加成功！

 </body>

 </html>

结果显示：

这样的话我们不管在前端页面提交多少次，后台也只有一个数据，而且我们自己在前端页面也无法感受到，是不是很神奇呢！