String jsonInput = "{"Appkey":"mEwead5ZQx0psM6b","Sign":"9d5cd39aab1adb6837e044e2eed0dd82","Timestamp":Timestamp,"TargetNodeId":"gdwalzz","TargetDatabaseId":"WalzzPaperERP","QueryID":0,"SQLCommand":"select * from Users"}";，mEwead5ZQx0psM6b，9d5cd39aab1adb6837e044e2eed0dd82等等几个，替换成变量提供给我，变量就用Appkey，Sign以此类推

以下是使用变量替换的代码示例：

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 appKey, String sign, long timestamp, String targetNodeId, String targetDatabaseId, int queryId, String sqlCommand) 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);

        String jsonInput = String.format("{\"Appkey\":\"%s\",\"Sign\":\"%s\",\"Timestamp\":%d,\"TargetNodeId\":\"%s\",\"TargetDatabaseId\":\"%s\",\"QueryID\":%d,\"SQLCommand\":\"%s\"}",
                appKey, sign, timestamp, targetNodeId, targetDatabaseId, queryId, sqlCommand);

        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 appKey = "mEwead5ZQx0psM6b";
            String sign = "9d5cd39aab1adb6837e044e2eed0dd82";
            long timestamp = 1690161912433L;
            String targetNodeId = "gdwalzz";
            String targetDatabaseId = "WalzzPaperERP";
            int queryId = 0;
            String sqlCommand = "select * from Users";

            String response = sendPostRequest(url, appKey, sign, timestamp, targetNodeId, targetDatabaseId, queryId, sqlCommand);
            System.out.println(response);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

在这个示例中，我添加了新的参数并将它们传递给 `sendPostRequest` 方法。你可以使用这些参数来动态构建 JSON 输入字符串。确保将这些变量替换为你实际的值。