如何深入理解并利用 HttpClient 源码进行高效网络通信？

HttpClient 是 Java 中用于发送 HTTP 请求的库，以下是一个简单的 HttpClient 示例，展示了如何使用它发送 GET 和 POST 请求：

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.URI;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.util.EntityUtils;
public class HttpClientExample {
    private static final String USER_AGENT = "Mozilla/5.0";
    public static void main(String[] args) throws Exception {
        HttpClient httpclient = new DefaultHttpClient();
        // 发送 GET 请求
        HttpGet httpget = new HttpGet("http://www.example.com");
        httpget.addHeader("UserAgent", USER_AGENT);
        HttpResponse response = httpclient.execute(httpget);
        System.out.println("GET Response Status: " + response.getStatusLine().getStatusCode());
        BufferedReader reader = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
        String line = null;
        while ((line = reader.readLine()) != null) {
            System.out.println(line);
        }
        reader.close();
        // 发送 POST 请求
        HttpPost httppost = new HttpPost("http://www.example.com");
        httppost.addHeader("UserAgent", USER_AGENT);
        httppost.setEntity(new StringEntity("{"key":"value"}"));
        response = httpclient.execute(httppost);
        System.out.println("POST Response Status: " + response.getStatusLine().getStatusCode());
        reader = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
        while ((line = reader.readLine()) != null) {
            System.out.println(line);
        }
        reader.close();
    }
}

这个示例使用了 Apache HttpClient 库，首先导入了所需的类，然后创建了一个 HttpClient 实例，我们创建了一个 HttpGet 对象来发送 GET 请求，并设置了 UserAgent 头，我们执行请求并打印响应状态码和响应内容，同样的过程也适用于 HttpPost 对象，用于发送 POST 请求。