CorsFilter 過濾器解決跨域的處理

@Component
public class CorsFilter {
    //這裡是前端請求頭,那個跨域就添加到這裡就行瞭
    private static final String headers = "User-Agent,Cache-Control,Content-type,Date,Server,withCredentials," +
            "appversion";
    @Override
    public void init(FilterConfig filterConfig)
            throws ServletException {
    }
    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
            throws IOException, ServletException {
        HttpServletResponse httpServletResponse = (HttpServletResponse) response;
        httpServletResponse.setHeader("Access-Control-Allow-Origin", "*");
        httpServletResponse.setHeader("Access-Control-Allow-Headers", headers);
        httpServletResponse.setHeader("Access-Control-Allow-Credentials", "true");
        httpServletResponse.setHeader("Access-Control-Allow-Methods",
                "GET, POST, PUT, DELETE, OPTIONS, HEAD");
        httpServletResponse.setHeader("Access-Control-Max-Age", "3600");
        httpServletResponse.setHeader("Access-Control-Expose-Headers", "usertoken");
        httpServletResponse.setHeader("Access-Control-Request-Headers", "usertoken");
        httpServletResponse.setHeader("Expires", "-1");
        httpServletResponse.setHeader("Cache-Control", "no-cache");
        httpServletResponse.setHeader("pragma", "no-cache");
        ServletRequest requestWrapper = null;
        if (request instanceof HttpServletRequest) {
            requestWrapper = new RequestWrapper((HttpServletRequest) request);
        }
        if (null == requestWrapper) {
            chain.doFilter(request, response);
        } else {
            chain.doFilter(requestWrapper, response);
        }
    }
    @Override
    public void destroy() {
    }
}

package com.grain.filter;
import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class CORSFilter implements Filter {
 @Override
 public void init(FilterConfig arg0) throws ServletException {
  // TODO Auto-generated method stub
  
 }
 @Override
 public void destroy() {
  // TODO Auto-generated method stub
  
 }

 @Override
 public void doFilter(ServletRequest req, ServletResponse res, FilterChain filterChain)
   throws IOException, ServletException {
  HttpServletRequest request = (HttpServletRequest) req;
        HttpServletResponse response = (HttpServletResponse) res;
  response.addHeader("Access-Control-Allow-Origin", "*");
        response.addHeader("Access-Control-Allow-Methods", "GET, POST, PUT, DELETE");
        response.addHeader("Access-Control-Allow-Headers", "Content-Type");
        response.addHeader("Access-Control-Max-Age", "1800");//30 min
        filterChain.doFilter(request, response); 
 }
}

<filter>
   <filter-name>CORSFilter</filter-name>
   <filter-class>com.grain.filter.CORSFilter</filter-class>
  </filter>
  <filter-mapping>
    <filter-name>CORSFilter</filter-name>
   <url-pattern>/*</url-pattern>
  </filter-mapping>