在所请求的资源上没有“Access-Control-Allow-Origin”头。 [英] No 'Access-Control-Allow-Origin' header is present on the requested resource.

问题描述

我使用SpringMVC.我想调用一个XML文件与Web服务为了解析它以后。问题是，我无法访问XML文件，我有这个错误：没有访问控制-Allow-Origin'头部存在于请求的资源上。我尝试了以下解决方案：

我创建了一个新类，目的是添加Access- - 请求的ressource上的-Origin头。这是类

  package com.mycompany.myapp; 
 
 import java.io.IOException; 
 import javax.servlet.Filter; 
 import javax.servlet.FilterChain; 
 import javax.servlet.FilterConfig; 
 import javax.servlet.ServletException; 
 import javax.servlet.ServletOutputStream; 
 import javax.servlet.ServletRequest; 
 import javax.servlet.ServletResponse; 
 import javax.servlet.http.HttpServletRequest; 
 import javax.servlet.http.HttpServletResponse; 
 
 public class JsonpFilter implements Filter {
 
 private String functionName; 
 
 @Override 
 public void destroy（）{
 
} 
 
 @Override 
 public void doFilter（ServletRequest request， ServletResponse servletResponse，
 FilterChain chain）throws IOException，ServletException {
 
 if（！（request instanceof HttpServletRequest））{
 throw new ServletException（This filter can
 +只处理HttpServletRequest请求）; 
} 
 
 HttpServletRequest httpRequest =（HttpServletRequest）request; 
 HttpServletResponse response =（HttpServletResponse）servletResponse; 
 
 if（isJSONPRequest（httpRequest））{
 ServletOutputStream out = response.getOutputStream（）; 
 
 out.println（getCallbackMethod（httpRequest）+（）; 
 chain.doFilter（request，response）; 
 out.println（）;）; 
 
 response.setContentType（text / javascript）; 
} else {
 response.addHeader（Access-Control-Allow-Origin，*）; 
 chain.doFilter（request，response）; 
} 
 
} 
 
 @Override 
 public void init（FilterConfig filterConfig）throws ServletException {
 this.functionName = filterConfig.getInitParameter encoding）; 
 if（this.functionName == null || this.functionName.length（）< = 0）{
 this.functionName =callback; 
} 
} 
 
 private String getCallbackMethod（HttpServletRequest httpRequest）{
 return httpRequest.getParameter（this.functionName）; 
} 
 
 private boolean isJSONPRequest（HttpServletRequest httpRequest）{
 String callbackMethod = getCallbackMethod（httpRequest）; 
 return（callbackMethod！= null&& callbackMethod.length（）> 0）; 
} 
  

}

<然后在我的web.xml文件中添加这两行：

 < display-name> DataServices< / display-name> ; 
 
< filter> 
< filter-name> JSONPRequestFilter< / filter-name> 
< filter-class> com.mycompany.myapp.JsonpFilter< / filter-class> 
< init-param> 
< param-name> functionName< / param-name> 
< param-value> callback< / param-value> 
< / init-param> 
< / filter> 
 
< filter-mapping> 
< filter-name> JSONPRequestFilter< / filter-name> 
< url-pattern> / *< / url-pattern> 
< / filter-mapping> 
  

我没有任何编译问题，但我仍然有同样的错误在控制台执行时间。所以，不考虑'Access-Control-Allow-Origin'头。
如果你能找到我的程序有什么问题，或者建议我另一个解决方案，我会非常感谢。

解决方案

要实现此接口

org.springframework.web.servlet.HandlerInterceptor

< blockquote>

这里是一个例子

  @Component 
 public class CORSInterceptor实现HandlerInterceptor {
 private static final Log LOG = LogFactory.getLog（CORSInterceptor.class）; 
 
 @Override 
 public boolean preHandle（HttpServletRequest请求，HttpServletResponse响应，对象处理程序）throws异常{
 
 LOG.trace（sending headers）; 
 response.setHeader（Access-Control-Allow-Origin，*）; 
 response.setHeader（Access-Control-Allow-Methods，POST，GET，PUT，DELETE）; 
 response.setHeader（Access-Control-Max-Age，3600）; 
 response.setHeader（Access-Control-Allow-Headers，x-requested-with）; 
 
 return true; 
} 
 
 @Override 
 public void postHandle（HttpServletRequest请求，HttpServletResponse响应，对象处理程序，ModelAndView modelAndView）
 throws异常{
 
 } 
 
 @Override 
 public void afterCompletion（HttpServletRequest请求，HttpServletResponse响应，对象处理程序，异常ex）
 throws异常{
 LOG.trace（afterCompletion被调用）; 
} 
 
} 
  

上下文

 < mvc：interceptors> 
< bean class =com.elm.mb.rest.interceptors.CORSInterceptor/> 
< / mvc：interceptors> 
  

I'm using SpringMVC.I want to call an XML file with web service in order to parse it later.The problem is that I can't access the XML file, I have got this error:No 'Access-Control-Allow-Origin' header is present on the requested resource.I have tried the solution below:

I created a new class which purpose is to add Access-Control-Allow-Origin' header on the requested ressource.This is the class

package com.mycompany.myapp;

import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class JsonpFilter implements Filter {

private String functionName;

@Override
public void destroy() {

}

@Override
public void doFilter(ServletRequest request, ServletResponse servletResponse,
                     FilterChain chain) throws IOException, ServletException {

    if (!(request instanceof HttpServletRequest)) {
        throw new ServletException("This filter can "
                                   + " only process HttpServletRequest requests");
    }

    HttpServletRequest httpRequest = (HttpServletRequest) request;
    HttpServletResponse response = (HttpServletResponse) servletResponse;

    if (isJSONPRequest(httpRequest)) {
        ServletOutputStream out = response.getOutputStream();

        out.println(getCallbackMethod(httpRequest) + "(");
        chain.doFilter(request, response);
        out.println(");");

        response.setContentType("text/javascript");
    } else {
        response.addHeader("Access-Control-Allow-Origin", "*");
        chain.doFilter(request, response);
    }

}

@Override
public void init(FilterConfig filterConfig) throws ServletException {
    this.functionName = filterConfig.getInitParameter("encoding");
    if(this.functionName == null || this.functionName.length() <= 0) {
        this.functionName = "callback";
    }
}

private String getCallbackMethod(HttpServletRequest httpRequest) {
    return httpRequest.getParameter(this.functionName);
}

private boolean isJSONPRequest(HttpServletRequest httpRequest) {
    String callbackMethod = getCallbackMethod(httpRequest);
    return (callbackMethod != null && callbackMethod.length() > 0);
}

}

then I add the these two lines in my web.xml file:

    <display-name>DataServices</display-name>

   <filter>
    <filter-name>JSONPRequestFilter</filter-name>
    <filter-class> com.mycompany.myapp.JsonpFilter</filter-class>
    <init-param>
        <param-name>functionName</param-name>
        <param-value>callback</param-value>
    </init-param>
</filter>

<filter-mapping>
    <filter-name>JSONPRequestFilter</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>

I don't have any complilation problem, but I still have the same error in the console at the execution time.So, the 'Access-Control-Allow-Origin' header isn't taken into account. Please,If you can find out what is wrong with my program, or suggest me another solution, I will be thankful

解决方案

To do this implement this interface

org.springframework.web.servlet.HandlerInterceptor

here is an example

@Component
public class CORSInterceptor implements HandlerInterceptor{
   private static final Log LOG = LogFactory.getLog(CORSInterceptor.class);

   @Override
   public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {

       LOG.trace("sending headers");
       response.setHeader("Access-Control-Allow-Origin", "*");
       response.setHeader("Access-Control-Allow-Methods", "POST, GET, PUT, DELETE");
       response.setHeader("Access-Control-Max-Age", "3600");
       response.setHeader("Access-Control-Allow-Headers", "x-requested-with");

       return true;
   }

   @Override
   public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView)
        throws Exception {

   }

   @Override
   public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex)
        throws Exception {
        LOG.trace("afterCompletion is called");
   }

}

Then add this line to your application context

<mvc:interceptors>
    <bean class="com.elm.mb.rest.interceptors.CORSInterceptor" />
</mvc:interceptors>

这篇关于在所请求的资源上没有“Access-Control-Allow-Origin”头。的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！