问题
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
回答1:
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>
来源：https://stackoverflow.com/questions/24098132/no-access-control-allow-origin-header-is-present-on-the-requested-resource