java从网络Url中下载文件例子

谁践踏了优雅 2022-08-02 10:59 191阅读 0赞

java从网络Url中下载文件例子：

import java.io.ByteArrayOutputStream;
    import java.io.File;
    import java.io.FileOutputStream;
    import java.io.IOException;
    import java.io.InputStream;
    import java.net.HttpURLConnection;
    import java.net.URL;
    
    
    public class Demo {
    	/**
    	 * 从网络Url中下载文件
    	 * @param urlStr
    	 * @param fileName
    	 * @param savePath
    	 * @throws IOException
    	 */
    	public static void downLoadFromUrl(String urlStr, String fileName,String savePath) throws IOException {
    		URL url = new URL(urlStr);
    		HttpURLConnection conn = (HttpURLConnection) url.openConnection();
    		// 设置超时间为3秒
    		conn.setConnectTimeout(3 * 1000);
    		// 防止屏蔽程序抓取而返回403错误
    		conn.setRequestProperty("User-Agent","Mozilla/4.0 (compatible; MSIE 5.0; Windows NT; DigExt)");
    		
    		// 得到输入流
    		InputStream inputStream = conn.getInputStream();
    		// 获取自己数组
    		byte[] getData = readInputStream(inputStream);
    		
    		// 文件保存位置
    		File saveDir = new File(savePath);
    		if (!saveDir.exists()) {
    			saveDir.mkdir();
    		}
    		File file = new File(saveDir + File.separator + fileName);
    		FileOutputStream fos = new FileOutputStream(file);
    		fos.write(getData);
    		if (fos != null) {
    			fos.close();
    		}
    		if (inputStream != null) {
    			inputStream.close();
    		}
    		
    		System.out.println("info:" + url + " download success");
    		
    	}
    	
    	/**
    	 * 从输入流中获取字节数组
    	 * @param inputStream
    	 * @return
    	 * @throws IOException
    	 */
    	public static byte[] readInputStream(InputStream inputStream)throws IOException {
    		byte[] buffer = new byte[1024];
    		int len = 0;
    		ByteArrayOutputStream bos = new ByteArrayOutputStream();
    		while ((len = inputStream.read(buffer)) != -1) {
    			bos.write(buffer, 0, len);
    		}
    		bos.close();
    		return bos.toByteArray();
    	}
    	
    	public static void main(String[] args) {
    		try {
    			downLoadFromUrl("http://avatar.csdn.net/9/B/0/1_xb12369.jpg","百度.jpg", "d:/images");
    		} catch (Exception e) {
    			e.printStackTrace();
    		}
    	}
    }

原文地址：[http://blog.csdn.net/xb12369/article/details/40543649][http_blog.csdn.net_xb12369_article_details_40543649]

[http_blog.csdn.net_xb12369_article_details_40543649]: http://blog.csdn.net/xb12369/article/details/40543649