java发送post请求json格式

可以使用以下代码示例发送Post请求并传递JSON格式数据：

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

public class HttpURLConnectionExample {

    private static final String targetURL = "http://example.com/api/test";

    public static void main(String[] args) {
        try {

            URL url = new URL(targetURL);
            HttpURLConnection connection = (HttpURLConnection) url.openConnection();
            connection.setRequestMethod("POST");
            connection.setRequestProperty("Content-Type", "application/json; utf-8");
            connection.setRequestProperty("Accept", "application/json");
            connection.setDoOutput(true);

            String jsonInputString = "{\"name\": \"John Smith\", \"email\": \"john.smith@example.com\"}";

            try(OutputStream os = connection.getOutputStream()) {
                byte[] input = jsonInputString.getBytes("utf-8");
                os.write(input, 0, input.length);
            }

            BufferedReader bufferedReader = new BufferedReader(
                    new InputStreamReader(connection.getInputStream(), "utf-8"));

            StringBuilder response = new StringBuilder();
            String responseLine = null;
            while ((responseLine = bufferedReader.readLine()) != null) {
                response.append(responseLine.trim());
            }
            System.out.println(response.toString());

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

请注意，此示例代码仅供参考，您需要根据实际需求进行修改。