如何用Java处理HTTP响应数据

在Java中处理HTTP响应数据，你可以使用多种库和方法。以下是一些常用的方法：

使用Java内置的HttpURLConnection

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;

public class HttpGetRequest {
    public static void main(String[] args) {
        try {
            URL url = new URL("http://example.com");
            HttpURLConnection connection = (HttpURLConnection) url.openConnection();
            connection.setRequestMethod("GET");

            int responseCode = connection.getResponseCode();
            System.out.println("Response Code : " + responseCode);

            BufferedReader in = new BufferedReader(new InputStreamReader(connection.getInputStream()));
            String inputLine;
            StringBuffer response = new StringBuffer();

            while ((inputLine = in.readLine()) != null) {
                response.append(inputLine);
            }
            in.close();

            // Print the response
            System.out.println(response.toString());

        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

使用Apache HttpClient

首先，你需要添加Apache HttpClient的依赖。如果你使用Maven，可以在pom.xml中添加以下依赖：

<dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpclient</artifactId>
    <version>4.5.13</version>
</dependency>

然后，你可以使用以下代码来发送HTTP请求并处理响应：

import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;

public class HttpClientExample {
    public static void main(String[] args) {
        try {
            HttpClient httpClient = HttpClients.createDefault();
            HttpGet request = new HttpGet("http://example.com");
            HttpResponse response = httpClient.execute(request);

            String responseBody = EntityUtils.toString(response.getEntity());
            System.out.println(responseBody);

        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

使用OkHttp

首先，添加OkHttp的依赖到你的项目中。如果你使用Maven，可以在pom.xml中添加以下依赖：

<dependency>
    <groupId>com.squareup.okhttp3</groupId>
    <artifactId>okhttp</artifactId>
    <version>4.9.0</version>
</dependency>

然后，使用以下代码发送HTTP请求并处理响应：

import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.Response;

public class OkHttpExample {
    public static void main(String[] args) {
        OkHttpClient client = new OkHttpClient();

        Request request = new Request.Builder()
                .url("http://example.com")
                .build();

        client.newCall(request).enqueue(new Callback() {
            @Override
            public void onFailure(Call call, IOException e) {
                e.printStackTrace();
            }

            @Override
            public void onResponse(Call call, Response response) throws IOException {
                if (response.isSuccessful()) {
                    String responseBody = response.body().string();
                    System.out.println(responseBody);
                }
            }
        });
    }
}

以上是三种在Java中处理HTTP响应数据的方法。你可以根据自己的需求和喜好选择合适的方法。