POST /api/walzzerpapi.asq HTTP/1.1 Host: www.walzz.com Content-Type: application/json cache-control: no-cache Postman-Token: 286f9b9a-e6ee-4e83-b37b-aae5d6ea7a5e { "Appkey": "mEwead5ZQx0psM6b", "Sign": "9d5cd39aab1adb6837e044e2eed0dd82", "Timestamp": 1690161912433, "TargetNodeId": "gdwalzz", "TargetDatabaseId": "WalzzPaperERP", "QueryID": 0, "SQLCommand": "select * from Users" }------WebKitFormBoundary7MA4YWxkTrZu0gW--，这是postman给出来的，给我提供一个封装好的java方法，做http请求。参考上面的

以下是一个封装好的 Java 方法，用于进行 HTTP 请求：

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

public class HttpRequestUtil {
    public static String sendPostRequest(String url, String jsonInput) throws IOException {
        URL requestUrl = new URL(url);
        HttpURLConnection connection = (HttpURLConnection) requestUrl.openConnection();
        connection.setRequestMethod("POST");
        connection.setRequestProperty("Content-Type", "application/json");
        connection.setRequestProperty("cache-control", "no-cache");
        connection.setRequestProperty("Postman-Token", "286f9b9a-e6ee-4e83-b37b-aae5d6ea7a5e");
        connection.setDoOutput(true);

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

        int responseCode = connection.getResponseCode();
        if (responseCode == HttpURLConnection.HTTP_OK) {
            BufferedReader reader = new BufferedReader(new InputStreamReader(connection.getInputStream()));
            StringBuilder response = new StringBuilder();
            String line;
            while ((line = reader.readLine()) != null) {
                response.append(line);
            }
            reader.close();
            return response.toString();
        } else {
            throw new IOException("HTTP request failed with code: " + responseCode);
        }
    }

    public static void main(String[] args) {
        try {
            String url = "http://www.walzz.com/api/walzzerpapi.asq";
            String jsonInput = "{\"Appkey\":\"mEwead5ZQx0psM6b\",\"Sign\":\"9d5cd39aab1adb6837e044e2eed0dd82\",\"Timestamp\":1690161912433,\"TargetNodeId\":\"gdwalzz\",\"TargetDatabaseId\":\"WalzzPaperERP\",\"QueryID\":0,\"SQLCommand\":\"select * from Users\"}";
            String response = sendPostRequest(url, jsonInput);
            System.out.println(response);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

请确保你已经将 `url` 和 `jsonInput` 替换为你实际的请求 URL 和 JSON 输入。这个方法会发送 POST 请求，并返回服务器的响应。