在平时开发中,若是网速比较慢的状况下, 用户提交表单后,发现服务器半天没有响应,用户可能觉得是本身没有提交表单,就会再点击提交按钮重复提交表单,因此在开发中咱们须要防止表单重复提交javascript
在网络延迟的状况下让用户有时间点击屡次submit致使表单重复提交html
表单提交后用户点击 刷新按钮致使表单重复提交java
用户提交表单后,点击后退按钮回退到表单页面后进行再次提交spring
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%> <!DOCTYPE HTML> <html> <head> <title>Form表单</title> <script type="text/javascript"> var isCommitted = false;//表单是否已经提交标识,默认为false function dosubmit(){ if(isCommitted==false){ isCommitted = true;//提交表单后,将表单是否已经提交标识设置为true return true;//返回true让表单正常提交 }else{ return false;//返回false那么表单将不提交 } } </script> </head> <body> <form action="${pageContext.request.contextPath}/servlet/DoFormServlet" onsubmit="return dosubmit()" method="post"> 用户名:<input type="text" name="username"> <input type="submit" value="提交" id="submit"> </form> </body> </html>
代码以下:服务器
function dosubmit(){ //获取表单提交按钮 var btnSubmit = document.getElementById("submit"); //将表单提交按钮设置为不可用,这样就能够避免用户再次点击提交按钮 btnSubmit.disabled= "disabled"; //返回true让表单能够正常提交 return true; }
在服务器端生成一个惟一的随机标识号,称为Token(令牌),同时在当前用户的Session域中保存这个Token。而后将Token发送到客户端的Form表单中,在Form表单中使用隐藏域来存储这个Token,表单提交的时候连同这个Token一块儿提交到服务器端,而后在服务器端判断客户端提交上来的Token与服务器端生成的Token是否一致,若是不一致,那就是重复提交了,此时服务器端就能够不处理重复提交的表单。若是相同则处理表单提交,处理完后清除当前用户的Session域中存储的标识号。网络
定义Token代码:mvc
@Target(ElementType.METHOD) @Retention(RetentionPolicy.RUNTIME) public @interface Token { boolean save() default false; boolean remove() default false; }
定义拦截器TokenInterceptor:app
public class TokenInterceptor extends HandlerInterceptorAdapter { @Override public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception { if (handler instanceof HandlerMethod) { HandlerMethod handlerMethod = (HandlerMethod) handler; Method method = handlerMethod.getMethod(); Token annotation = method.getAnnotation(Token.class); if (annotation != null) { boolean needSaveSession = annotation.save(); if (needSaveSession) { request.getSession(false).setAttribute("token", UUID.randomUUID().toString()); } boolean needRemoveSession = annotation.remove(); if (needRemoveSession) { if (isRepeatSubmit(request)) { return false; } request.getSession(false).removeAttribute("token"); } } return true; } else { return super.preHandle(request, response, handler); } } private boolean isRepeatSubmit(HttpServletRequest request) { String serverToken = (String)request.getSession(false).getAttribute("token"); if (serverToken == null) { return true; } String clientToken = request.getParameter("token"); if (clientToken == null) { return true; } if(!serverToken.equals(clientToken)){ return true; } return false; } }
而后在springmvc的配置文件中加入:dom
<!--配置拦截器--> <mvc:interceptors> <!--配置token拦截器,防止用户重复提交数据--> <mvc:interceptor> <mvc:mapping path="/**"/> <bean class="com.simple.interceptor.TokenInterceptor"/> </mvc:interceptor> </mvc:interceptors>
在jsp页面form里面添加下面的代码:jsp
<input type="hidden" name="token" value="${token}">
使用上面在须要生成token的controller上增长@Token(save=true) ,须要检查重复提交的controller上添加@Token(remove=true)
@RequestMapping("/save") @AvoidDuplicateSubmission(save= true) public synchronized ModelAndView save(ExecutionUnit unit, HttpServletRequest request, HttpServletResponse response) throws Exception { @RequestMapping("/edit") @AvoidDuplicateSubmission(remove= true) public ModelAndView edit(Integer id, HttpServletRequest request) throws Exception {