HttpClient和HttpURLConnection的区别

Posted 2023-04-24

参考技术A HttpURLConnection是一种多用途、轻量极的HTTP客户端，使用它来进行HTTP操作可以适用于大多数的应用程序。虽然HttpURLConnection的API提供的比较简单，但是同时这也使得我们可以更加容易地去使用和扩展它。但是早期的版本BUG比较多，最新比较方便扩展。
早期为了更好地处理向Web站点请求，包括处理Session、Cookie等细节问题，Apache开源组织提供了一个HttpClient项目，看它的名称就知道，它是一个简单的HTTP客户端（并不是浏览器），可以用于发送HTTP请求，接收HTTP响应。但不会缓存服务器的响应，不能执行html页面中嵌入的javascript代码；也不会对页面内容进行任何解析、处理。简单来说，HttpClient就是一个增强版的HttpURLConnection，HttpURLConnection可以做的事情HttpClient全部可以做；HttpURLConnection没有提供的有些功能，HttpClient也提供了，但它只是关注于如何发送请求、接收响应，以及管理HTTP连接。 参考技术B 首先：在 JDK 的 java.net 包中已经提供了访问 HTTP 协议的基本功能：HttpURLConnection。但是对于大部分应用程序来说，JDK 库本身提供的功能还不够丰富和灵活。
在android中，androidSDK中集成了Apache的HttpClient模块，用来提供高效的、最新的、功能丰富的支持 HTTP 协议工具包，并且它支持 HTTP 协议最新的版本和建议。使用HttpClient可以快速开发出功能强大的Http程序。
其次：HttpClient是个很不错的开源框架，封装了访问http的请求头，参数，内容体，响应等等，

HttpURLConnection是java的标准类，什么都没封装，用起来太原始，不方便，比如重访问的自定义，以及一些高级功能等。
HttpClient就是一个增强版的HttpURLConnection，HttpURLConnection可以做的事情HttpClient全部可以做；HttpURLConnection没有提供的有些功能，HttpClient也提供了，但它只是关注于如何发送请求、接收响应，以及管理HTTP连接。

使用HttpClient发送请求、接收响应很简单，只要如下几步即可：
1.创建HttpClient对象。
2.如果需要发送GET请求，创建HttpGet对象；如果需要发送POST请求，创建HttpPost对象。
3.如果需要发送请求参数，可调用HttpGet、HttpPost共同的setParams(HetpParams params)方法来添加请求参数；对于HttpPost对象而言，也可调用setEntity(HttpEntity entity)方法来设置请求参数。
4.调用HttpClient对象的execute(HttpUriRequest request)发送请求，执行该方法返回一个HttpResponse。
5.调用HttpResponse的getAllHeaders()、getHeaders(String name)等方法可获取服务器的响应头；调用HttpResponse的getEntity()方法可获取HttpEntity对象，该对象包装了服务器的响应内容。程序可通过该对象获取服务器的响应内容。

Android’s HTTP Clients (httpClient 和 httpURLConnect 区别)

来源自: http://android-developers.blogspot.jp/2011/09/androids-http-clients.html

 

Most network-connected Android apps will use HTTP to send and receive data. Android includes two HTTP clients: HttpURLConnection and Apache HTTP Client. Both support HTTPS, streaming uploads and downloads, configurable timeouts, IPv6 and connection pooling.

Apache HTTP Client

DefaultHttpClient and its sibling AndroidHttpClient are extensible HTTP clients suitable for web browsers. They have large and flexible APIs. Their implementation is stable and they have few bugs.

But the large size of this API makes it difficult for us to improve it without breaking compatibility. The Android team is not actively working on Apache HTTP Client.

HttpURLConnection

HttpURLConnection is a general-purpose, lightweight HTTP client suitable for most applications. This class has humble beginnings, but its focused API has made it easy for us to improve steadily.

Prior to Froyo, HttpURLConnection had some frustrating bugs. In particular, calling close() on a readable InputStream could poison the connection pool. Work around this by disabling connection pooling:

private void disableConnectionReuseIfNecessary() {
    // HTTP connection reuse which was buggy pre-froyo
    if (Integer.parseInt(Build.VERSION.SDK) < Build.VERSION_CODES.FROYO) {
        System.setProperty("http.keepAlive", "false");
    }
}

In Gingerbread, we added transparent response compression. HttpURLConnection will automatically add this header to outgoing requests, and handle the corresponding response:

Accept-Encoding: gzip

Take advantage of this by configuring your Web server to compress responses for clients that can support it. If response compression is problematic, the class documentation shows how to disable it.

Since HTTP’s Content-Length header returns the compressed size, it is an error to use getContentLength() to size buffers for the uncompressed data. Instead, read bytes from the response until InputStream.read() returns -1.

We also made several improvements to HTTPS in Gingerbread. HttpsURLConnection attempts to connect with Server Name Indication (SNI) which allows multiple HTTPS hosts to share an IP address. It also enables compression and session tickets. Should the connection fail, it is automatically retried without these features. This makes HttpsURLConnection efficient when connecting to up-to-date servers, without breaking compatibility with older ones.

In Ice Cream Sandwich, we are adding a response cache. With the cache installed, HTTP requests will be satisfied in one of three ways:

• Fully cached responses are served directly from local storage. Because no network connection needs to be made such responses are available immediately.

• Conditionally cached responses must have their freshness validated by the webserver. The client sends a request like “Give me /foo.png if it changed since yesterday” and the server replies with either the updated content or a 304 Not Modified status. If the content is unchanged it will not be downloaded!

• Uncached responses are served from the web. These responses will get stored in the response cache for later.

Use reflection to enable HTTP response caching on devices that support it. This sample code will turn on the response cache on Ice Cream Sandwich without affecting earlier releases:

private void enableHttpResponseCache() {
    try {
        long httpCacheSize = 10 * 1024 * 1024; // 10 MiB
        File httpCacheDir = new File(getCacheDir(), "http");
        Class.forName("android.net.http.HttpResponseCache")
            .getMethod("install", File.class, long.class)
            .invoke(null, httpCacheDir, httpCacheSize);
    } catch (Exception httpResponseCacheNotAvailable) {
    }
}

You should also configure your Web server to set cache headers on its HTTP responses.

Which client is best?

Apache HTTP client has fewer bugs on Eclair and Froyo. It is the best choice for these releases.

For Gingerbread and better, HttpURLConnection is the best choice. Its simple API and small size makes it great fit for Android. Transparent compression and response caching reduce network use, improve speed and save battery. New applications should use HttpURLConnection; it is where we will be spending our energy going forward.