java post请求代码

Sure, here's an example of how to make a POST request in Java:

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

public class PostRequestExample {
    public static void main(String[] args) throws Exception {
        URL url = new URL("http://example.com/api/post");
        HttpURLConnection connection = (HttpURLConnection) url.openConnection();
        connection.setRequestMethod("POST");
        connection.setRequestProperty("Content-Type", "application/json");
        connection.setDoOutput(true);

        String data = "{ \"name\": \"John\", \"age\": 30 }";
        OutputStream outputStream = connection.getOutputStream();
        outputStream.write(data.getBytes());
        outputStream.flush();

        BufferedReader reader = new BufferedReader(new InputStreamReader(connection.getInputStream()));
        String response = "";
        String line;
        while ((line = reader.readLine()) != null) {
            response += line;
        }
        reader.close();
        connection.disconnect();

        System.out.println("Response: " + response);
    }
}

This example sends a JSON payload to the URL `http://example.com/api/post` using a POST request. The payload is `{ "name": "John", "age": 30 }` and the response from the server is printed to the console.