support charset when build Reader for Response.Body

core/src/main/java/feign/Response.java

@@ -221,6 +221,11 @@ public interface Body extends Closeable {
      * It is the responsibility of the caller to close the stream.
      */
     Reader asReader() throws IOException;
+
+    /**
+     *
+     */
+    Reader asReader(Charset charset) throws IOException;
   }
 
   private static final class InputStreamBody implements Response.Body {
@@ -260,6 +265,12 @@ public Reader asReader() throws IOException {
       return new InputStreamReader(inputStream, UTF_8);
     }
 
+    @Override
+    public Reader asReader(Charset charset) throws IOException {
+      checkNotNull(charset, "charset should not be null");
+      return new InputStreamReader(inputStream, charset);
+    }
+
     @Override
     public void close() throws IOException {
       inputStream.close();
@@ -309,6 +320,12 @@ public Reader asReader() throws IOException {
       return new InputStreamReader(asInputStream(), UTF_8);
     }
 
+    @Override
+    public Reader asReader(Charset charset) throws IOException {
+      checkNotNull(charset, "charset should not be null");
+      return new InputStreamReader(asInputStream(), charset);
+    }
+
     @Override
     public void close() throws IOException {}
 

core/src/test/java/feign/FeignBuilderTest.java

@@ -21,6 +21,7 @@
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.Reader;
+import java.nio.charset.Charset;
 import java.lang.reflect.InvocationHandler;
 import java.lang.reflect.Method;
 import java.lang.reflect.Type;
@@ -399,6 +400,11 @@ public Reader asReader() throws IOException {
                     return original.body().asReader();
                   }
 
+                  @Override
+                  public Reader asReader(Charset charset) throws IOException {
+                    return original.body().asReader(charset);
+                  }
+
                   @Override
                   public void close() throws IOException {
                     closed.set(true);

httpclient/src/main/java/feign/httpclient/ApacheHttpClient.java

@@ -34,6 +34,7 @@
 import java.io.InputStream;
 import java.io.InputStreamReader;
 import java.io.Reader;
+import java.nio.charset.Charset;
 import java.io.UnsupportedEncodingException;
 import java.net.MalformedURLException;
 import java.net.URI;
@@ -52,7 +53,7 @@
 /**
  * This module directs Feign's http requests to Apache's
  * <a href="https://hc.apache.org/httpcomponents-client-ga/">HttpClient</a>. Ex.
- * 
+ *
  * <pre>
  * GitHub github = Feign.builder().client(new ApacheHttpClient()).target(GitHub.class,
  * "https://api.github.com");
@@ -224,6 +225,12 @@ public Reader asReader() throws IOException {
         return new InputStreamReader(asInputStream(), UTF_8);
       }
 
+      @Override
+      public Reader asReader(Charset charset) throws IOException {
+        Util.checkNotNull(charset, "charset should not be null");
+        return new InputStreamReader(asInputStream(), charset);
+      }
+
       @Override
       public void close() throws IOException {
         EntityUtils.consume(entity);

okhttp/src/main/java/feign/okhttp/OkHttpClient.java

@@ -22,6 +22,7 @@
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.Reader;
+import java.nio.charset.Charset;
 import java.util.Collection;
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
@@ -142,6 +143,11 @@ public InputStream asInputStream() throws IOException {
       public Reader asReader() throws IOException {
         return input.charStream();
       }
+
+      @Override
+      public Reader asReader(Charset charset) throws IOException {
+        return asReader();
+      }
     };
   }