Java里HTTP响应如何处理

在Java中，处理HTTP响应通常是通过使用HTTP客户端库来实现的。这些库提供了发送HTTP请求和处理HTTP响应的功能。以下是一些常用的Java HTTP客户端库：

1. HttpURLConnection：这是Java标准库中的一个类，用于发送和接收HTTP请求。要使用HttpURLConnection，首先需要创建一个URL对象，然后调用其openConnection()方法来获取一个HttpURLConnection对象。接下来，可以设置请求方法（如GET、POST等）、请求头等信息，并通过输入输出流来发送和接收数据。

示例代码：

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

public class HttpUrlConnectionExample {
    public static void main(String[] args) throws Exception {
        URL url = new URL("https://api.example.com/data");
        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;
        StringBuilder content = new StringBuilder();

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

        in.close();
        connection.disconnect();

        System.out.println("Response Content: " + content.toString());
    }
}

2. Apache HttpClient：这是一个流行的第三方HTTP客户端库，提供了更丰富的功能和更简洁的API。要使用Apache HttpClient，首先需要将其添加到项目依赖中。

Maven依赖：

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

示例代码：

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 ApacheHttpClientExample {
    public static void main(String[] args) throws Exception {
        HttpClient httpClient = HttpClients.createDefault();
        HttpGet httpGet = new HttpGet("https://api.example.com/data");

        HttpResponse httpResponse = httpClient.execute(httpGet);
        int statusCode = httpResponse.getStatusLine().getStatusCode();
        System.out.println("Response Code: " + statusCode);

        String responseContent = EntityUtils.toString(httpResponse.getEntity());
        System.out.println("Response Content: " + responseContent);
    }
}

3. OkHttp：这是另一个流行的第三方HTTP客户端库，提供了简洁的API和高效的性能。要使用OkHttp，首先需要将其添加到项目依赖中。

Maven依赖：

<dependency>
    <groupId>com.squareup.okhttp3</groupId>
    <artifactId>okhttp</artifactId>
    <version>4.9.1</version>
</dependency>

示例代码：

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

public class OkHttpExample {
    public static void main(String[] args) throws Exception {
        OkHttpClient httpClient = new OkHttpClient();
        Request request = new Request.Builder()
                .url("https://api.example.com/data")
                .build();

        Response response = httpClient.newCall(request).execute();
        int statusCode = response.code();
        System.out.println("Response Code: " + statusCode);

        String responseContent = response.body().string();
        System.out.println("Response Content: " + responseContent);
    }
}

这些库都可以用于处理HTTP响应。你可以根据项目需求和个人喜好选择合适的库。