基於Spring Security+Spring MVC的web應用，為了防止跨站提交攻擊，通常會配置csrf，即：

1     <http ...>
2         ...
3         <csrf />        
4     </http>

如果應用中有Post方式訪問的Rest服務(參考下面的程式碼)，會很不幸的發現，所有POST方式請求的服務會呼叫失敗。

1     @RequestMapping(value = "/user/create", method = RequestMethod.POST)
2     @ResponseBody
 
3     public UserInfo createUser(@RequestBody(required = true) UserInfo user,
4             HttpServletRequest request, HttpServletResponse response)
5             throws Exception {
6         ...
7     }

原因在於：啟用csrf後，所有http請求都被會CsrfFilter攔截，而CsrfFilter中有一個私有類DefaultRequiresCsrfMatcher

 1     private
 
 static final class DefaultRequiresCsrfMatcher implements RequestMatcher {
 2         private Pattern allowedMethods = Pattern.compile("^(GET|HEAD|TRACE|OPTIONS)$");
 3 
 4         /* (non-Javadoc)
 5          * @see org.springframework.security.web.util.matcher.RequestMatcher#matches(javax.servlet.http.HttpServletRequest)
 
 6          */
 7         public boolean matches(HttpServletRequest request) {
 8             return !allowedMethods.matcher(request.getMethod()).matches();
 9         }
10     }

從這段原始碼可以發現，POST方法被排除在外了，也就是說只有GET|HEAD|TRACE|OPTIONS這4類方法會被放行，其它Method的http請求，都要驗證_csrf的token是否正確，而通常post方式呼叫rest服務時，又沒有_csrf的token，所以校驗失敗。

解決方法：自己弄一個Matcher

 1 package com.cnblogs.yjmyzz.utils;
 2 
 3 import java.util.List;
 4 import java.util.regex.Pattern;
 5 
 6 import javax.servlet.http.HttpServletRequest;
 7 
 8 import org.springframework.security.web.util.matcher.RequestMatcher;
 9 
10 public class CsrfSecurityRequestMatcher implements RequestMatcher {
11     private Pattern allowedMethods = Pattern
12             .compile("^(GET|HEAD|TRACE|OPTIONS)$");
13 
14     public boolean matches(HttpServletRequest request) {
15 
16         if (execludeUrls != null && execludeUrls.size() > 0) {
17             String servletPath = request.getServletPath();
18             for (String url : execludeUrls) {
19                 if (servletPath.contains(url)) {
20                     return false;
21                 }
22             }
23         }
24         return !allowedMethods.matcher(request.getMethod()).matches();
25     }
26 
27     /**
28      * 需要排除的url列表
29      */
30     private List<String> execludeUrls;
31 
32     public List<String> getExecludeUrls() {
33         return execludeUrls;
34     }
35 
36     public void setExecludeUrls(List<String> execludeUrls) {
37         this.execludeUrls = execludeUrls;
38     }
39 }

這裡添加了一個屬性execludeUrls，允許人為排除哪些url。

然後在配置檔案裡，這樣修改：

 1     <http entry-point-ref="loginEntryPoint" use-expressions="true">
 2         ...
 3         <intercept-url pattern="/rest/**" access="permitAll" />
 4         ...
 5         <csrf request-matcher-ref="csrfSecurityRequestMatcher"/>        
 6     </http>
 7     
 8     <beans:bean id="csrfSecurityRequestMatcher" class="com.cnblogs.yjmyzz.utils.CsrfSecurityRequestMatcher">
 9         <beans:property name="execludeUrls">
10             <beans:list>
11                 <beans:value>/rest/</beans:value>
12             </beans:list>
13         </beans:property>
14     </beans:bean>

這裡約定所有/rest/開頭的都是Rest服務地址，上面的配置就把/rest/排除在csrf驗證的範圍之外了.