java 代码实现下载微信支付交易账单

以下是 Java 代码实现下载微信支付交易账单的示例：

import java.io.*;
import java.net.HttpURLConnection;
import java.net.URL;

public class DownloadWeChatBill {
    public static void main(String[] args) {
        String urlStr = "https://api.mch.weixin.qq.com/pay/downloadbill";
        String data = "appid=APPID&mch_id=MCH_ID&nonce_str=NONCE_STR&sign=SIGN&bill_date=BILL_DATE&bill_type=BILL_TYPE";
        String filePath = "D:/bill.csv";

        try {
            URL url = new URL(urlStr);
            HttpURLConnection conn = (HttpURLConnection) url.openConnection();
            conn.setRequestMethod("POST");
            conn.setDoOutput(true);
            conn.setDoInput(true);
            conn.setUseCaches(false);
            conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
            conn.setRequestProperty("Content-Length", String.valueOf(data.getBytes().length));

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

            InputStream inputStream = conn.getInputStream();
            byte[] buffer = new byte[1024];
            int len;
            FileOutputStream fileOutputStream = new FileOutputStream(new File(filePath));
            while ((len = inputStream.read(buffer)) != -1) {
                fileOutputStream.write(buffer, 0, len);
            }
            fileOutputStream.close();
            inputStream.close();

            System.out.println("微信支付交易账单下载成功！");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}