用java写一个文件下载

您好，以下是一个简单的使用 Java 进行文件下载的示例代码：

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

public class FileDownloader {
    public static void main(String[] args) {
        String fileUrl = "http://example.com/file.zip";
        String saveDir = "D:/Downloads/";

        try {
            URL url = new URL(fileUrl);
            URLConnection conn = url.openConnection();
            InputStream inputStream = conn.getInputStream();

            String fileName = fileUrl.substring(fileUrl.lastIndexOf("/") + 1);
            String saveFilePath = saveDir + fileName;

            FileOutputStream outputStream = new FileOutputStream(saveFilePath);

            int bytesRead = -1;
            byte[] buffer = new byte[1024];

            while ((bytesRead = inputStream.read(buffer)) != -1) {
                outputStream.write(buffer, 0, bytesRead);
            }

            outputStream.close();
            inputStream.close();

            System.out.println("文件下载完成！");
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

该代码中，您需要设置文件的 URL 和保存路径，然后通过 URLConnection 获取文件流并写入本地文件。