解决nginx代理spring boot tomcat工程报错

问题场景：在未通过nginx代理情况下所有业务逻辑正常，但是经常nginx代理后某些业务就报空指针错误。

报错提示：

java.lang.NullPointerException
        at org.springframework.web.util.WebUtils.isSameOrigin(WebUtils.java:816)
        at org.springframework.web.cors.DefaultCorsProcessor.processRequest(DefaultCorsProcessor.java:76)
        at org.springframework.web.servlet.handler.AbstractHandlerMapping$CorsInterceptor.preHandle(AbstractHandlerMapping.java:503)
        at org.springframework.web.servlet.HandlerExecutionChain.applyPreHandle(HandlerExecutionChain.java:134)
        at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:956)
        at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:895)
        at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:967)
        at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:869)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:648)

 找到代码：

	public static boolean isSameOrigin(HttpRequest request) {
		String origin = request.getHeaders().getOrigin();
		if (origin == null) {
			return true;
		}
		UriComponents actualUrl = UriComponentsBuilder.fromHttpRequest(request).build();
		UriComponents originUrl = UriComponentsBuilder.fromOriginHeader(origin).build();
		return (actualUrl.getHost().equals(originUrl.getHost()) && getPort(actualUrl) == getPort(originUrl));
	}

 看这个代码逻辑是会去判断实际的请求地址和源地址是否一致。

解决方法：在nginx代理层修改请求头为浏览器的请求来源。

        location /mgmt {
                proxy_pass http://sunbar_mgmt/mgmt;
                proxy_set_header        X-Real-IP       $remote_addr;
                proxy_set_header        Host            $host;
                proxy_set_header        X-Forwarded-For $proxy_add_x_forwarded_for;
                proxy_pass_request_headers              on;
        }