java post请求代码

以下是使用 Java 发送 POST 请求的示例代码：

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

public class HttpPostExample {

    public static void main(String[] args) {
        String url = "http://example.com/api/endpoint";
        String data = "param1=value1&param2=value2";

        try {
            URL endpoint = new URL(url);
            HttpURLConnection connection = (HttpURLConnection) endpoint.openConnection();
            connection.setRequestMethod("POST");
            connection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
            connection.setDoOutput(true);

            OutputStream outputStream = connection.getOutputStream();
            outputStream.write(data.getBytes());
            outputStream.flush();

            if (connection.getResponseCode() != HttpURLConnection.HTTP_OK) {
                throw new RuntimeException("Failed : HTTP error code : " + connection.getResponseCode());
            }

            BufferedReader responseReader = new BufferedReader(new InputStreamReader((connection.getInputStream())));

            String output;
            System.out.println("Output from Server:\n");
            while ((output = responseReader.readLine()) != null) {
                System.out.println(output);
            }

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

其中，`url` 和 `data` 分别表示请求的 URL 和请求参数。我们使用 `HttpURLConnection` 类来发送请求，并设置请求方法为 `POST`。设置请求头的 `Content-Type` 为 `application/x-www-form-urlencoded`，表示请求参数为表单形式。然后，我们将请求参数写入输出流，并发送请求。最后，我们读取响应数据，并在控制台打印出来。