(Java)网路路径文件下载
此篇时讲通过网路路径将文件以二进制流响应到浏览器，文件名称是前台所管控的。
下面是下载文件方法的主体：
1 import org.slf4j.Logger; 2 import org.slf4j.LoggerFactory; 3 import org.springframework.stereotype.Component; 4 5 import javax.servlet.ServletOutputStream; 6 import javax.servlet.http.HttpServletResponse; 7 import java.io.IOException; 8 import java.io.InputStream; 9 import java.net.HttpURLConnection; 10 import java.net.URL; 11 12 /** 13 * 文件下载 14 * Date: 2020/10/29 15 * @author 时恰好那个i 16 */ 17 @Component 18 public class FileDownloadUtil { 19 20 private static final Logger LOGGER = LoggerFactory.getLogger(FileDownloadUtil.class); 21 22 23 /** 24 * 从网络Url中下载文件 25 * @param fileUrl 网路路径 26 * @param fileName 文件名称 27 */ 28 public void downLoadFromUrl(String fileUrl,String fileName, HttpServletResponse response) { 29 ServletOutputStream outputStream = null; 30 InputStream inputStream = null; 31 try { 32 URL url = new URL(fileUrl); 33 HttpURLConnection conn = (HttpURLConnection)url.openConnection(); 34 //设置超时间为3秒 35 conn.setConnectTimeout(3 * 1000); 36 //防止屏蔽程序抓取而返回403错误 37 conn.setRequestProperty("User-Agent", "Mozilla/4.0 (compatible; MSIE 5.0; Windows NT; DigExt)"); 38 39 //得到输入流 40 inputStream = conn.getInputStream(); 41 response.setContentType("application/json;charset=UTF-8"); 42 // response.setHeader("Content-Disposition", "attachment;fileName=" + URLEncoder.encode(fileName, "UTF-8") ); 43 response.setHeader("Cache-Control", "no-cache"); 44 outputStream = response.getOutputStream(); 45 byte[] b = new byte[1024]; 46 int len = 0; 47 while((len = inputStream.read(b)) > 0) { 48 outputStream.write(b, 0, len); 49 } 50 outputStream.flush(); 51 } catch (IOException e) { 52 LOGGER.info("文件下载失败"); 53 e.printStackTrace(); 54 } finally { 55 if (outputStream != null) { 56 try { 57 outputStream.close(); 58 } catch (IOException e) { 59 e.printStackTrace(); 60 } 61 } 62 if (inputStream != null) { 63 try { 64 inputStream.close(); 65 } catch (IOException e) { 66 e.printStackTrace(); 67 } 68 } 69 } 70 } 71 72 }
