最近在使用Apache的httpclient的时候，maven引用了最新版本4.3,发现Idea提示DefaultHttpClient等常用的类已经不推荐使用了，之前在使用4.2.3版本的时候，还没有被deprecated。去看了下官方文档，确实不推荐使用了，点击此处详情。

• DefaultHttpClient —> CloseableHttpClient
• HttpResponse —> CloseableHttpResponse

官方给出了新api的样例，如下。

Get方法：

Get方法：

    CloseableHttpClient httpclient = HttpClients.createDefault();

    HttpGet httpGet = new HttpGet("http://targethost/homepage");

    CloseableHttpResponse response1 = httpclient.execute(httpGet);

    // The underlying HTTP connection is still held by the response object

    // to allow the response content to be streamed directly from the network socket.

    // In order to ensure correct deallocation of system resources

    // the user MUST either fully consume the response content  or abort request

    // execution by calling CloseableHttpResponse#close().

    //建立的http连接，仍旧被response1保持着，允许我们从网络socket中获取返回的数据

    //为了释放资源，我们必须手动消耗掉response1或者取消连接（使用CloseableHttpResponse类的close方法）

    try {

        System.out.println(response1.getStatusLine());

        HttpEntity entity1 = response1.getEntity();

        // do something useful with the response body

        // and ensure it is fully consumed

        EntityUtils.consume(entity1);

    } finally {

        response1.close();

    }

Post方法：

    HttpPost httpPost = new HttpPost("http://targethost/login");

    //拼接参数

    List <NameValuePair> nvps = new ArrayList <NameValuePair>();

    nvps.add(new BasicNameValuePair("username", "vip"));

    nvps.add(new BasicNameValuePair("password", "secret"));

    httpPost.setEntity(new UrlEncodedFormEntity(nvps));

    CloseableHttpResponse response2 = httpclient.execute(httpPost);

    try {

        System.out.println(response2.getStatusLine());

        HttpEntity entity2 = response2.getEntity();

        // do something useful with the response body

        // and ensure it is fully consumed

        //消耗掉response

        EntityUtils.consume(entity2);

    } finally {

        response2.close();

    }

再往下看HttpClients的源码，具体的实现都在HttpClientBuilder的build方法中，有兴趣的可以去apache看源码。

    /**

    * Creates {@link CloseableHttpClient} instance with default

    * configuration.

    */

    public static CloseableHttpClient createDefault() {

        return HttpClientBuilder.create().build();

    }