本文介绍如何使用token来防止前端重复提交的问题。

目录

• 1.思路
• 2.拦截器源码实现
• 3.注解源码
• 4.拦截器的配置
• 5.使用指南
• 6.结语

思路

1.添加拦截器，拦截需要防重复提交的请求

核心源码

拦截器源码实现

/** * com.xxx.interceptor.TokenInterceptor.java * Copyright 2018 Lifangyu, Inc. All rights reserved. */package com.xxx.common.interceptor;import org.apache.log4j.Logger;import org.springframework.web.method.HandlerMethod;import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import java.lang.reflect.Method;import java.util.Random;import java.util.UUID;/** * Desc:防重复提交的拦截器 * 
 * Created by lifangyu on 2018/02/27. */public class TokenInterceptor extends HandlerInterceptorAdapter {    Logger logger = Logger.getLogger(TokenInterceptor.class);    static String splitFlag = "_";    @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) {                return true;            }                        boolean needSaveSession = annotation.add();            if (needSaveSession) {                Random random = new Random();                String uuid = UUID.randomUUID().toString().replace(splitFlag, String.valueOf(random.nextInt(100000)));                String tokenValue = String.valueOf(System.currentTimeMillis());                request.setAttribute("token", uuid + splitFlag + tokenValue);                // session 中 token 的key 每次都是变化的[适应浏览器 打开多个带有token的页面不会有覆盖session的key]                request.getSession(true).setAttribute(uuid, tokenValue);            }            boolean needRemoveSession = annotation.remove();            if (needRemoveSession) {                if (isRepeatSubmit(request)) {                    logger.warn("please don't repeat submit,url:" + request.getServletPath());                    return false;                }                String clinetToken = request.getParameter("token");                if (clinetToken != null && clinetToken.indexOf(splitFlag) > -1) {                    request.getSession(true).removeAttribute(clinetToken.split("_")[0]);                }            }                        return true;        } else {            return super.preHandle(request, response, handler);        }    }    /**     * 判断是否是重复提交     *     * @param request     * @return     */    private boolean isRepeatSubmit(HttpServletRequest request) {        String clinetToken = request.getParameter("token");        if (clinetToken == null) {            return true;        }        if (clinetToken.indexOf(splitFlag) <= -1) {            return false;        }                String uuid = clinetToken.split("_")[0];        String token = clinetToken.split("_")[1];        String serverToken = (String) request.getSession(true).getAttribute(uuid);        if (serverToken == null) {            return true;        }        if (!serverToken.equals(token)) {            return true;        }                return false;    }}复制代码

注解源码

/** * com.xxx.interceptor.Token.java * Copyright 2018 Lifangyu, Inc. All rights reserved. */package com.xxx.common.interceptor;import java.lang.annotation.ElementType;import java.lang.annotation.Retention;import java.lang.annotation.RetentionPolicy;import java.lang.annotation.Target;/** * Desc:Token 注解 * 
 * Created by lifangyu on 2018/02/27. */@Target(ElementType.METHOD)@Retention(RetentionPolicy.RUNTIME)public @interface Token {    /**     * 添加token的开关[true：添加；false:不添加，default：false]     *     * @return     */    boolean add() default false;    /**     * 移除token的开关[true：删除；false:不删除，default：false]     *     * @return     */    boolean remove() default false;}复制代码

拦截器的配置

在springMVC的servlet配置文件中配置拦截器

    
    	
     	
     		
      		
      	
     
    复制代码

使用指南

1.在进入页面的controller方法上添加注解@Token(add=true)

@Token(add = true)@RequestMapping("toXxxHtml")public String toXxxHtml(Model mv) {   ......   return "xxx/xxxHtml";}复制代码

2.在页面toXxxHtml.html添加

    
        ......   
        
        ......
    
复制代码

3.在防止重复提交的controller方法上添加@Token(remove = true)

@Token(remove = true)@RequestMapping("addXxx")public String addXxx() throws Exception {   ......   return "redirect:toXxxHtml.do";}复制代码

结语

到此本文就结束了，欢迎大家继续关注更多Spring案例。

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