如何在Java中实现HTTP客户端请求？

原创梦里梦外; 2024-12-11 12:51 20阅读 0赞

在Java中，我们可以使用HttpURLConnection或者更现代的HttpClient来实现HTTP客户端请求。

以下是一个使用HttpURLConnection的例子：

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

public class HttpClientExample {
    public static void main(String[] args) {
        // 创建URL对象
        URL url = new URL("http://example.com");

// 创建HttpURLConnection对象
        HttpURLConnection connection = (HttpURLConnection) url.openConnection();

// 设置请求方法（GET或POST）
        connection.setRequestMethod("GET");

// 获取响应码，判断请求是否成功
        int responseCode = connection.getResponseCode();
        System.out.println("Response Code: " + responseCode);

// 读取响应内容
        BufferedReader reader = new BufferedReader(new InputStreamReader(connection.getInputStream())));

String line;
        while ((line = reader.readLine()) != null) {
            System.out.println(line);
        }

// 关闭连接
        connection.disconnect();
    }
}
```

如果使用更现代的 HttpClient，代码会更为简洁：

```java
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;

public class HttpClientExampleModern {
    public static void main(String[] args) {
        // 创建HttpClient对象
        CloseableHttpClient httpClient = HttpClients.createDefault();

try {
            // 创建HttpGet请求对象
            HttpGet httpGet = new HttpGet("http://example.com");

// 执行HTTP请求
            CloseableHttpResponse response = httpClient.execute(httpGet);

// 检查响应状态码，表示请求是否成功
            int statusCode = response.getStatusLine().getStatusCode();
            System.out.println("Status Code: " + statusCode);

// 读取响应内容
            BufferedReader reader = new BufferedReader(new InputStreamReader(response.getInputStream()))));

String line;
            while ((line = reader.readLine()) != null) {
                System.out.println(line);
            }

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

// 关闭连接
        response.close();
        httpClient.close();
    }
}
```