Java：使用URL下載圖片為何圖片下載不完全呢？

問題描述

public class Client { public static void main(String[] args) {try { URL url = new URL('http://www.iteye.com/upload/logo/user/1177132/a7159cc1-b11a-3122-9a9d-5183d6c6ba99.jpg'); HttpURLConnection connection = (HttpURLConnection) url.openConnection(); connection.setConnectTimeout(5 * 1000); InputStream inputStream = connection.getInputStream(); byte[] tmp = new byte[1024]; int length; OutputStream outputStream = new FileOutputStream('E:' + File.separator + 'eee.jpg'); while ((length = inputStream.read(tmp)) != -1) {outputStream.write(tmp, 0, length); } outputStream.close(); inputStream.close();} catch (Exception e) { e.printStackTrace();} }}

圖片URL：http://www.iteye.com/upload/l...圖片有3K，但我下載后圖片只有2K而且圖片是錯誤的這是為什么呢？

問題解答

你把代碼改成這樣試試

public class Client { public static void main(String[] args) {try { URL url = new URL('http://www.iteye.com/upload/logo/user/1177132/a7159cc1-b11a-3122-9a9d-5183d6c6ba99.jpg'); HttpURLConnection connection = (HttpURLConnection) url.openConnection(); connection.setRequestProperty('User-Agent', 'Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.19 Safari/537.36'); connection.setConnectTimeout(5 * 1000); InputStream inputStream = connection.getInputStream(); byte[] tmp = new byte[1024]; int length; OutputStream outputStream = new FileOutputStream('E:' + File.separator + 'eee.jpg'); while ((length = inputStream.read(tmp)) != -1) {outputStream.write(tmp, 0, length); } outputStream.close(); inputStream.close();} catch (Exception e) { e.printStackTrace();} }}

不添加UA下載下來的文件其實是這樣的

outputStream.close()之前，先調用outputStream.flush()，這個方法能強制把輸出流緩沖全部寫出來。你前邊的都沒錯，就差一步了。

這是我用你的代碼讀到的東西。

目標禁止了，為connection添加一個user-agent屬性吧。