### Question:
HttpClientUtils { public static String get(String url, Map<String, String> params, RegistryClientConfig config) throws Exception { HttpURLConnection httpURLConnection = create(getFullPath(url, params), config); httpURLConnection.setRequestMethod("GET"); BufferedReader reader = null; try { StringBuilder stringBuffer = new StringBuilder(); int responseCode = httpURLConnection.getResponseCode(); if (responseCode == HttpURLConnection.HTTP_OK) { String charset = httpURLConnection.getContentEncoding(); if (charset != null) { reader = new BufferedReader(new InputStreamReader( httpURLConnection.getInputStream(), charset)); } else { reader = new BufferedReader(new InputStreamReader( httpURLConnection.getInputStream())); } String strCurrentLine; while ((strCurrentLine = reader.readLine()) != null) { stringBuffer.append(strCurrentLine).append("\n"); } if (stringBuffer.length() > 0 && stringBuffer.charAt(stringBuffer.length() - 1) == '\n') { stringBuffer.deleteCharAt(stringBuffer.length() - 1); } return stringBuffer.toString(); } } finally { httpURLConnection.disconnect(); if (null != reader) { reader.close(); } } return null; }  static String get(String url, Map<String, String> params, RegistryClientConfig config);  }### Answer:
@Test public void testGet() { String url = "http: Map<String, String> map = new HashMap<String, String>(); map.put("x", "1"); map.put("y", "2"); RegistryClientConfig clientConfig = new DefaultRegistryClientConfigBuilder().build(); try { HttpClientUtils.get(url, map, clientConfig); Assert.fail(); } catch (Exception e) { } url = "http: try { HttpClientUtils.get(url, map, clientConfig); } catch (Exception e) { Assert.fail(e.getMessage()); } url = "http: try { Assert.assertNull(HttpClientUtils.get(url, map, clientConfig)); } catch (Exception e) { Assert.fail(e.getMessage()); } }