code: @Test public void testRevertRegister2(){
    String key="dubbo.test.api.HelloService";
    Map<String,Map<String,String>> register=new HashMap<String,Map<String,String>>();
    Map<String,String> service=new HashMap<String,String>();
    service.put("dubbo://127.0.0.1:20880/com.xxx.XxxService",null);
    register.put(key,service);
    Map<String,Map<String,String>> newRegister=UrlUtils.revertRegister(register);
    Map<String,Map<String,String>> expectedRegister=new HashMap<String,Map<String,String>>();
    service.put("dubbo://127.0.0.1:20880/com.xxx.XxxService",null);
    expectedRegister.put("dubbo.test.api.HelloService",service);
    assertEquals(expectedRegister,newRegister);
  }
  