java post请求调用文件下载接口并保存文件到本地

在Java中，你可以使用`java.net.URLConnection`或者第三方库如`Apache HttpClient`或`OkHttp`来发送POST请求并下载文件。以下是一个基本示例，使用`URLConnection`：

import java.io.FileOutputStream;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;

public class FileDownloadExample {
    public static void main(String[] args) {
        String downloadUrl = "http://example.com/file-to-download"; // 替换为你实际的文件下载地址
        String saveFilePath = "/path/to/save/downloaded/file"; // 替换为你想要保存的位置

        try {
            URL url = new URL(downloadUrl);
            HttpURLConnection connection = (HttpURLConnection) url.openConnection();
            connection.setRequestMethod("POST"); // 设置请求方法为POST，如果需要可以添加其他请求头
            
            // 如果有post数据，设置连接的Content-Type和POST数据
            if (!connection.getRequestProperty("Content-Type").isEmpty()) {
                connection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
            }
            
            connection.connect(); // 连接服务器
            int responseCode = connection.getResponseCode();
            if (responseCode == HttpURLConnection.HTTP_OK) { // 检查HTTP状态码是否为200
                InputStream inputStream = connection.getInputStream();
                
                FileOutputStream outputStream = new FileOutputStream(saveFilePath);
                byte[] buffer = new byte[4096];
                int bytesRead;
                while ((bytesRead = inputStream.read(buffer)) != -1) {
                    outputStream.write(buffer, 0, bytesRead);
                }

                outputStream.close();
                inputStream.close();
                System.out.println("File downloaded successfully.");
            } else {
                System.err.println("Failed to download file. Server responded with code: " + responseCode);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}