Java中如何处理HTTP错误响应

在Java中，处理HTTP错误响应通常涉及到使用HTTP客户端库（如HttpClient、HttpURLConnection等）来发起请求并检查响应状态码。以下是使用这些库处理HTTP错误响应的示例：

1. 使用HttpClient（Java 11及以上版本）：

import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;

public class HttpClientExample {
    public static void main(String[] args) {
        HttpClient httpClient = HttpClient.newHttpClient();
        HttpRequest request = HttpRequest.newBuilder()
                .uri(URI.create("https://api.example.com/data"))
                .GET()
                .build();

        try {
            HttpResponse<String> response = httpClient.send(request, HttpResponse.BodyHandlers.ofString());

            if (response.statusCode() >= 200 && response.statusCode() < 300) {
                System.out.println("请求成功，响应内容: " + response.body());
            } else {
                System.out.println("请求失败，HTTP状态码: " + response.statusCode());
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

2. 使用HttpURLConnection：

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

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

            int responseCode = connection.getResponseCode();

            if (responseCode >= 200 && responseCode < 300) {
                BufferedReader in = new BufferedReader(new InputStreamReader(connection.getInputStream()));
                String inputLine;
                StringBuilder content = new StringBuilder();

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

                in.close();
                System.out.println("请求成功，响应内容: " + content.toString());
            } else {
                System.out.println("请求失败，HTTP状态码: " + responseCode);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

在这两个示例中，我们首先发起一个HTTP GET请求，然后检查响应状态码。如果状态码表示成功（2xx），则处理响应内容；否则，输出错误状态码。注意，这些示例仅处理GET请求，但你可以根据需要修改它们以支持其他HTTP方法。