android studio HttpURLConnection请求出问题

Question

用HttpURLConnection请求百度首页成功，(GET请求)
请求这个地址也成功：http://10.207.112.191:8080，说明后台服务器可用
但请求这个地址不成功：http://10.207.112.191:8080/user
/user后台测试代码：

用的是SpringMVC

@RequestMapping(value = "/user", method = RequestMethod.GET)  
   public void Reply(HttpServletResponse response) throws IOException {  
       PrintWriter out = response.getWriter();
       System.out.println("来自安卓");
       out.print("OK");
       out.flush();      
       out.close();
   }

logcat:

D/NetworkSecurityConfig: No Network Security Config specified, using platform default
D/Tag: 未进入http
W/System.err: java.io.FileNotFoundException: http://10.207.112.191:8080/user
W/System.err:     at com.android.okhttp.internal.huc.HttpURLConnectionImpl.getInputStream(HttpURLConnectionImpl.java:250)
W/System.err:     at hope.HttpUtil.HttpUtil$1.run(HttpUtil.java:43)
W/System.err:     at java.lang.Thread.run(Thread.java:761)