springMVC中基于token防止表单重复提交方法

本文介绍了springMVC中基于token防止表单重复提交方法，分享给大家，具体如下：

实现思路：

在springmvc配置文件中加入拦截器的配置，拦截两类请求，一类是到页面的，一类是提交表单的。当转到页面的请求到来时，生成token的名字和token值，一份放到Redis缓存中，一份放传给页面表单的隐藏域。（注：这里之所以使用redis缓存，是因为tomcat服务器是集群部署的，要保证token的存储介质是全局线程安全的，而redis是单线程的）

当表单请求提交时，拦截器得到参数中的tokenName和token，然后到缓存中去取token值，如果能匹配上，请求就通过，不能匹配上就不通过。这里的tokenName生成时也是随机的，每次请求都不一样。而从缓存中取token值时，会立即将其删除（删与读是原子的，无线程安全问题）。

实现方式：

TokenInterceptor.Java

package com.xxx.www.common.interceptor; 

import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.log4j.Logger;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;
import com.xxx.cache.redis.IRedisCacheClient;
import com.xxx.common.utility.JsonUtil;
import com.xxx.www.common.utils.TokenHelper; 

/**
 *
 * @see TokenHelper
 */
public class TokenInterceptor extends HandlerInterceptorAdapter
{ 

  private static Logger log = Logger.getLogger(TokenInterceptor.class);
  private static Map<String , String> viewUrls = new HashMap<String , String>();
  private static Map<String , String> actionUrls = new HashMap<String , String>();
  private Object clock = new Object(); 

  @Autowired
  private IRedisCacheClient redisCacheClient;
  static
  {
    viewUrls.put("/user/regc/brandregnamecard/", "GET");
    viewUrls.put("/user/regc/regnamecard/", "GET"); 

    actionUrls.put("/user/regc/brandregnamecard/", "POST");
    actionUrls.put("/user/regc/regnamecard/", "POST");
  }
  {
    TokenHelper.setRedisCacheClient(redisCacheClient);
  } 

  /**
   * 拦截方法，添加or验证token
   */
  @Override
  public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception
  {
    String url = request.getRequestURI();
    String method = request.getMethod();
    if(viewUrls.keySet().contains(url) && ((viewUrls.get(url)) == null || viewUrls.get(url).equals(method)))
    {
      TokenHelper.setToken(request);
      return true;
    }
    else if(actionUrls.keySet().contains(url) && ((actionUrls.get(url)) == null || actionUrls.get(url).equals(method)))
    {
      log.debug("Intercepting invocation to check for valid transaction token.");
      return handleToken(request, response, handler);
    }
    return true;
  } 

  protected boolean handleToken(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception
  {
    synchronized(clock)
    {
      if(!TokenHelper.validToken(request))
      {
        System.out.println("未通过验证...");
        return handleInvalidToken(request, response, handler);
      }
    }
    System.out.println("通过验证...");
    return handleValidToken(request, response, handler);
  } 

  /**
   * 当出现一个非法令牌时调用
   */
  protected boolean handleInvalidToken(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception
  {
    Map<String , Object> data = new HashMap<String , Object>();
    data.put("flag", 0);
    data.put("msg", "请不要频繁操作！");
    writeMessageUtf8(response, data);
    return false;
  } 

  /**
   * 当发现一个合法令牌时调用.
   */
  protected boolean handleValidToken(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception
  {
    return true;
  } 

  private void writeMessageUtf8(HttpServletResponse response, Map<String , Object> json) throws IOException
  {
    try
    {
      response.setCharacterEncoding("UTF-8");
      response.getWriter().print(JsonUtil.toJson(json));
    }
    finally
    {
      response.getWriter().close();
    }
  } 

}

TokenHelper.java

package com.xxx.www.common.utils; 

import java.math.BigInteger;
import java.util.Map;
import java.util.Random;
import javax.servlet.http.HttpServletRequest;
import org.apache.log4j.Logger;
import com.xxx.cache.redis.IRedisCacheClient; 

/**
 * TokenHelper
 *
 */
public class TokenHelper
{ 

  /**
   * 保存token值的默认命名空间
   */
  public static final String TOKEN_NAMESPACE = "xxx.tokens"; 

  /**
   * 持有token名称的字段名
   */
  public static final String TOKEN_NAME_FIELD = "xxx.token.name";
  private static final Logger LOG = Logger.getLogger(TokenHelper.class);
  private static final Random RANDOM = new Random(); 

  private static IRedisCacheClient redisCacheClient;// 缓存调用,代替session,支持分布式 

  public static void setRedisCacheClient(IRedisCacheClient redisCacheClient)
  {
    TokenHelper.redisCacheClient = redisCacheClient;
  } 

  /**
   * 使用随机字串作为token名字保存token
   *
   * @param request
   * @return token
   */
  public static String setToken(HttpServletRequest request)
  {
    return setToken(request, generateGUID());
  } 

  /**
   * 使用给定的字串作为token名字保存token
   *
   * @param request
   * @param tokenName
   * @return token
   */
  private static String setToken(HttpServletRequest request, String tokenName)
  {
    String token = generateGUID();
    setCacheToken(request, tokenName, token);
    return token;
  } 

  /**
   * 保存一个给定名字和值的token
   *
   * @param request
   * @param tokenName
   * @param token
   */
  private static void setCacheToken(HttpServletRequest request, String tokenName, String token)
  {
    try
    {
      String tokenName0 = buildTokenCacheAttributeName(tokenName);
      redisCacheClient.listLpush(tokenName0, token);
      request.setAttribute(TOKEN_NAME_FIELD, tokenName);
      request.setAttribute(tokenName, token);
    }
    catch(IllegalStateException e)
    {
      String msg = "Error creating HttpSession due response is commited to client. You can use the CreateSessionInterceptor or create the HttpSession from your action before the result is rendered to the client: " + e.getMessage();
      LOG.error(msg, e);
      throw new IllegalArgumentException(msg);
    }
  } 

  /**
   * 构建一个基于token名字的带有命名空间为前缀的token名字
   *
   * @param tokenName
   * @return the name space prefixed session token name
   */
  public static String buildTokenCacheAttributeName(String tokenName)
  {
    return TOKEN_NAMESPACE + "." + tokenName;
  } 

  /**
   * 从请求域中获取给定token名字的token值
   *
   * @param tokenName
   * @return the token String or null, if the token could not be found
   */
  public static String getToken(HttpServletRequest request, String tokenName)
  {
    if(tokenName == null)
    {
      return null;
    }
    Map params = request.getParameterMap();
    String[] tokens = (String[]) (String[]) params.get(tokenName);
    String token;
    if((tokens == null) || (tokens.length < 1))
    {
      LOG.warn("Could not find token mapped to token name " + tokenName);
      return null;
    } 

    token = tokens[0];
    return token;
  } 

  /**
   * 从请求参数中获取token名字
   *
   * @return the token name found in the params, or null if it could not be found
   */
  public static String getTokenName(HttpServletRequest request)
  {
    Map params = request.getParameterMap(); 

    if(!params.containsKey(TOKEN_NAME_FIELD))
    {
      LOG.warn("Could not find token name in params.");
      return null;
    } 

    String[] tokenNames = (String[]) params.get(TOKEN_NAME_FIELD);
    String tokenName; 

    if((tokenNames == null) || (tokenNames.length < 1))
    {
      LOG.warn("Got a null or empty token name.");
      return null;
    } 

    tokenName = tokenNames[0]; 

    return tokenName;
  } 

  /**
   * 验证当前请求参数中的token是否合法，如果合法的token出现就会删除它，它不会再次成功合法的token
   *
   * @return 验证结果
   */
  public static boolean validToken(HttpServletRequest request)
  {
    String tokenName = getTokenName(request); 

    if(tokenName == null)
    {
      LOG.debug("no token name found -> Invalid token ");
      return false;
    } 

    String token = getToken(request, tokenName); 

    if(token == null)
    {
      if(LOG.isDebugEnabled())
      {
        LOG.debug("no token found for token name " + tokenName + " -> Invalid token ");
      }
      return false;
    } 

    String tokenCacheName = buildTokenCacheAttributeName(tokenName);
    String cacheToken = redisCacheClient.listLpop(tokenCacheName); 

    if(!token.equals(cacheToken))
    {
      LOG.warn("xxx.internal.invalid.token Form token " + token + " does not match the session token " + cacheToken + ".");
      return false;
    } 

    // remove the token so it won't be used again 

    return true;
  } 

  public static String generateGUID()
  {
    return new BigInteger(165,RANDOM).toString(36).toUpperCase();
  } 

}

spring-mvc.xml

<!-- token拦截器-->
  <bean id="tokenInterceptor" class="com.xxx.www.common.interceptor.TokenInterceptor"></bean>
  <bean class="org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping">
    <property name="interceptors">
      <list>
        <ref bean="tokenInterceptor"/>
      </list>
    </property>
  </bean>

input.jsp 在form中加如下内容：

<input type="hidden" name="<%=request.getAttribute("xxx.token.name") %>" value="<%=token %>"/> 

<input type="hidden" name="xxx.token.name" value="<%=request.getAttribute("xxx.token.name") %>"/>

当前这里也可以用类似于struts2的自定义标签来做。

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