keep the HttpUtil and marked it deprecated

apollo-client/src/main/java/com/ctrip/framework/apollo/util/http/HttpUtil.java

@@ -0,0 +1,171 @@
+package com.ctrip.framework.apollo.util.http;
+
+import com.ctrip.framework.apollo.build.ApolloInjector;
+import com.ctrip.framework.apollo.exceptions.ApolloConfigException;
+import com.ctrip.framework.apollo.exceptions.ApolloConfigStatusCodeException;
+import com.ctrip.framework.apollo.util.ConfigUtil;
+import com.google.common.base.Function;
+import com.google.common.io.CharStreams;
+import com.google.gson.Gson;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.lang.reflect.Type;
+import java.net.HttpURLConnection;
+import java.net.URL;
+import java.nio.charset.StandardCharsets;
+import java.util.Map;
+
+/**
+ * @author Jason Song([email protected])
+ * @deprecated in favor of the interface {@link HttpClient} and it's default implementation {@link DefaultHttpClient}
+ */
+@Deprecated
+public class HttpUtil implements HttpClient {
+  private ConfigUtil m_configUtil;
+  private static final Gson GSON = new Gson();
+
+  /**
+   * Constructor.
+   */
+  public HttpUtil() {
+    m_configUtil = ApolloInjector.getInstance(ConfigUtil.class);
+  }
+
+  /**
+   * Do get operation for the http request.
+   *
+   * @param httpRequest  the request
+   * @param responseType the response type
+   * @return the response
+   * @throws ApolloConfigException if any error happened or response code is neither 200 nor 304
+   */
+  @Override
+  public <T> HttpResponse<T> doGet(HttpRequest httpRequest, final Class<T> responseType) {
+    Function<String, T> convertResponse = new Function<String, T>() {
+      @Override
+      public T apply(String input) {
+        return GSON.fromJson(input, responseType);
+      }
+    };
+
+    return doGetWithSerializeFunction(httpRequest, convertResponse);
+  }
+
+  /**
+   * Do get operation for the http request.
+   *
+   * @param httpRequest  the request
+   * @param responseType the response type
+   * @return the response
+   * @throws ApolloConfigException if any error happened or response code is neither 200 nor 304
+   */
+  @Override
+  public <T> HttpResponse<T> doGet(HttpRequest httpRequest, final Type responseType) {
+    Function<String, T> convertResponse = new Function<String, T>() {
+      @Override
+      public T apply(String input) {
+        return GSON.fromJson(input, responseType);
+      }
+    };
+
+    return doGetWithSerializeFunction(httpRequest, convertResponse);
+  }
+
+  private <T> HttpResponse<T> doGetWithSerializeFunction(HttpRequest httpRequest,
+      Function<String, T> serializeFunction) {
+    InputStreamReader isr = null;
+    InputStreamReader esr = null;
+    int statusCode;
+    try {
+      HttpURLConnection conn = (HttpURLConnection) new URL(httpRequest.getUrl()).openConnection();
+
+      conn.setRequestMethod("GET");
+
+      Map<String, String> headers = httpRequest.getHeaders();
+      if (headers != null && headers.size() > 0) {
+        for (Map.Entry<String, String> entry : headers.entrySet()) {
+          conn.setRequestProperty(entry.getKey(), entry.getValue());
+        }
+      }
+
+      int connectTimeout = httpRequest.getConnectTimeout();
+      if (connectTimeout < 0) {
+        connectTimeout = m_configUtil.getConnectTimeout();
+      }
+
+      int readTimeout = httpRequest.getReadTimeout();
+      if (readTimeout < 0) {
+        readTimeout = m_configUtil.getReadTimeout();
+      }
+
+      conn.setConnectTimeout(connectTimeout);
+      conn.setReadTimeout(readTimeout);
+
+      conn.connect();
+
+      statusCode = conn.getResponseCode();
+      String response;
+
+      try {
+        isr = new InputStreamReader(conn.getInputStream(), StandardCharsets.UTF_8);
+        response = CharStreams.toString(isr);
+      } catch (IOException ex) {
+        /**
+         * according to https://docs.oracle.com/javase/7/docs/technotes/guides/net/http-keepalive.html,
+         * we should clean up the connection by reading the response body so that the connection
+         * could be reused.
+         */
+        InputStream errorStream = conn.getErrorStream();
+
+        if (errorStream != null) {
+          esr = new InputStreamReader(errorStream, StandardCharsets.UTF_8);
+          try {
+            CharStreams.toString(esr);
+          } catch (IOException ioe) {
+            //ignore
+          }
+        }
+
+        // 200 and 304 should not trigger IOException, thus we must throw the original exception out
+        if (statusCode == 200 || statusCode == 304) {
+          throw ex;
+        }
+        // for status codes like 404, IOException is expected when calling conn.getInputStream()
+        throw new ApolloConfigStatusCodeException(statusCode, ex);
+      }
+
+      if (statusCode == 200) {
+        return new HttpResponse<>(statusCode, serializeFunction.apply(response));
+      }
+
+      if (statusCode == 304) {
+        return new HttpResponse<>(statusCode, null);
+      }
+    } catch (ApolloConfigStatusCodeException ex) {
+      throw ex;
+    } catch (Throwable ex) {
+      throw new ApolloConfigException("Could not complete get operation", ex);
+    } finally {
+      if (isr != null) {
+        try {
+          isr.close();
+        } catch (IOException ex) {
+          // ignore
+        }
+      }
+
+      if (esr != null) {
+        try {
+          esr.close();
+        } catch (IOException ex) {
+          // ignore
+        }
+      }
+    }
+
+    throw new ApolloConfigStatusCodeException(statusCode,
+        String.format("Get operation failed for %s", httpRequest.getUrl()));
+  }
+
+}