HttpClient自动处理Gzip,Deflate压缩

在4.4版本之后通过RequestConfig创建的httpclient能够自动处理压缩数据

如下RequestConfig.class源码

 /**
     * Determines whether compressed entities should be decompressed automatically.
     * <p>
     * Default: {@code true}
     * </p>
     *
     * @since 4.4
     */
    public boolean isDecompressionEnabled() {
        return decompressionEnabled;
    }

 ResponseContentEncoding （implements HttpResponseInterceptor）类中有处理带压缩header的数据。

 @Override
    public void process(
            final HttpResponse response,
            final HttpContext context) throws HttpException, IOException {
        final HttpEntity entity = response.getEntity();

        final HttpClientContext clientContext = HttpClientContext.adapt(context);
        final RequestConfig requestConfig = clientContext.getRequestConfig();
        // entity can be null in case of 304 Not Modified, 204 No Content or similar
        // check for zero length entity.
        if (requestConfig.isDecompressionEnabled() && entity != null && entity.getContentLength() != 0) {
            final Header ceheader = entity.getContentEncoding();
            if (ceheader != null) {
                final HeaderElement[] codecs = ceheader.getElements();
                for (final HeaderElement codec : codecs) {
                    final String codecname = codec.getName().toLowerCase(Locale.ROOT);
                    final InputStreamFactory decoderFactory = decoderRegistry.lookup(codecname);
                    if (decoderFactory != null) {
                        response.setEntity(new DecompressingEntity(response.getEntity(), decoderFactory));
                        response.removeHeaders("Content-Length");
                        response.removeHeaders("Content-Encoding");
                        response.removeHeaders("Content-MD5");
                    } else {
                        if (!"identity".equals(codecname)) {
                            throw new HttpException("Unsupported Content-Coding: " + codec.getName());
                        }
                    }
                }
            }
        }
    }

Gzip\Deflate 的解压缩处理类。

/**
     * @since 4.4
     */
    public ResponseContentEncoding(final Lookup<InputStreamFactory> decoderRegistry) {
        this.decoderRegistry = decoderRegistry != null ? decoderRegistry :
            RegistryBuilder.<InputStreamFactory>create()
                    .register("gzip", GZIP)
                    .register("x-gzip", GZIP)
                    .register("deflate", DEFLATE)
                    .build();
    }

总结

     Httpclient对于原生的HttpConnection做了很多封装处理。方便的同时，当然相比原生的东西，速度上会下降一些，但是带来了很大的便利性。