Java HTTP客户端：GET/POST请求示例

原创傷城~ 2024-12-01 05:15 3阅读 0赞

在Java中，我们可以使用HttpURLConnection或者HttpClient来发送HTTP GET或POST请求。这里我将提供这两种方法的示例。

1. 使用HttpURLConnection：

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

public class HttpClientGETExample {
    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");

// 如果是POST请求，需要设置请求体
        // connection.setDoOutput(true);
        // String postBody = "Your POST body";
        // byte[] postBytes = postBody.getBytes();
        // connection.getOutputStream().write(postBytes);

// 获取响应状态码
        int responseCode = connection.getResponseCode();

// 打印响应状态码
        System.out.println("Response Code: " + responseCode);

// 读取并打印响应内容（如果是POST请求，需要处理请求体）
        BufferedReader reader = new BufferedReader(new InputStreamReader(connection.getInputStream()))));
        String outputLine;
        while ((outputLine = reader.readLine()) != null)) {
            System.out.println(outputLine);
        }
    }
}
```

2. 使用HttpClient：

如果你使用的是Apache HttpClient，那么示例会稍微有所不同。这里我提供一个基本的GET请求示例：

```java
import org.apache.http.HttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;

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

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

try (HttpResponse response = httpClient.execute(httpGet)) {

// 获取响应状态码
            int statusCode = response.getStatusLine().getStatusCode();
            System.out.println("Response Status Code: " + statusCode);

// 如果状态码为200（OK），则读取并打印响应内容
            if (statusCode == 200) {
                String responseContent = EntityUtils.toString(response.getEntity(), "UTF-8"));
                System.out.println("Response Content: " + responseContent);
            }

} catch (Exception e) {
            System.err.println(e.getMessage());
            e.printStackTrace();
        }
    }
}
```

以上示例展示了如何使用Java的HttpURLConnection或者HttpClient发送GET请求。