文件操作相关utils
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; /** * 文件操作公共类 */ public class FileUtil { /** * 删除文件 * @param filePath */ public static void deleteFile(String filePath) { try { File fileTemp = new File(filePath); if (fileTemp.exists()) { fileTemp.delete(); } } catch (Exception e) { e.printStackTrace(); } } /** * 删除文件夹 * @param dir * @return */ public static boolean deleteDir(File dir) { if (dir.isDirectory()) { String[] children = dir.list(); // 递归删除目录中的子目录下 for (int i = 0; i < children.length; i++) { boolean success = deleteDir(new File(dir, children[i])); if (!success) { return false; } } } return dir.delete(); } /** * 清空目录下所有文件 * @param path * @return */ public static boolean deleteDir(String path){ File file = new File(path); if(!file.exists()){//判断是否待删除目录是否存在 System.err.println("The dir are not exists!"); return false; } String[] content = file.list();//取得当前目录下所有文件和文件夹 for(String name : content){ File temp = new File(path, name); if(temp.isDirectory()){//判断是否是目录 deleteDir(temp.getAbsolutePath());//递归调用,删除目录里的内容 temp.delete();//删除空目录 }else{ if(!temp.delete()){//直接删除文件 System.err.println("Failed to delete " + name); } } } return true; } /** * 根据url下载图片 * @param imgurl * @return */ public static String downImg(String imgurl) { String path = ""; try { URL url = new URL(imgurl); 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 String dirPath = "C:/logs/demo/img"; File filedir = new File(dirPath); if (!filedir.exists()) { filedir.mkdirs(); } path = String.format("%s/%s.jpg", dirPath, StringUtil.getUUID()); File files = new File(path); FileOutputStream fos = new FileOutputStream(files); fos.write(getData); if (fos != null) { fos.close(); } if (inputStream != null) { inputStream.close(); } } catch (Exception e) { e.printStackTrace(); } return path; } /** * 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(); } /** 常用文件的文件头如下:(以前六位为准) JPEG (jpg),文件头:FFD8FF PNG (png),文件头:89504E47 GIF (gif),文件头:47494638 TIFF (tif),文件头:49492A00 Windows Bitmap (bmp),文件头:424D CAD (dwg),文件头:41433130 Adobe Photoshop (psd),文件头:38425053 Rich Text Format (rtf),文件头:7B5C727466 XML (xml),文件头:3C3F786D6C HTML (html),文件头:68746D6C3E Email [thorough only] (eml),文件头:44656C69766572792D646174653A Outlook Express (dbx),文件头:CFAD12FEC5FD746F Outlook (pst),文件头:2142444E MS Word/Excel (xls.or.doc),文件头:D0CF11E0 MS Access (mdb),文件头:5374616E64617264204A WordPerfect (wpd),文件头:FF575043 Postscript (eps.or.ps),文件头:252150532D41646F6265 Adobe Acrobat (pdf),文件头:255044462D312E Quicken (qdf),文件头:AC9EBD8F Windows Password (pwl),文件头:E3828596 ZIP Archive (zip),文件头:504B0304 RAR Archive (rar),文件头:52617221 Wave (wav),文件头:57415645 AVI (avi),文件头:41564920 Real Audio (ram),文件头:2E7261FD Real Media (rm),文件头:2E524D46 MPEG (mpg),文件头:000001BA MPEG (mpg),文件头:000001B3 Quicktime (mov),文件头:6D6F6F76 Windows Media (asf),文件头:3026B2758E66CF11 MIDI (mid),文件头:4D546864 */ public static String getFileType(byte[] bytes) { StringBuilder stringBuilder = new StringBuilder(); if (bytes == null || bytes.length <= 0) { return null; } for (int i = 0; i < bytes.length; i++) { int v = bytes[i] & 0xFF; String hv = Integer.toHexString(v); if (hv.length() < 2) { stringBuilder.append(0); } stringBuilder.append(hv); } String fileHead = stringBuilder.toString().toUpperCase(); if (fileHead.startsWith("FFD8FF")) { return "jpg"; } else if (fileHead.startsWith("89504E")) { return "png"; } else if (fileHead.startsWith("474946")) { return "jif"; } else if (fileHead.startsWith("41564920")) { return "avi"; } else if (fileHead.startsWith("3C3F786D6C")) { return "xml"; } else if (fileHead.startsWith("504B0304")) { return "zip"; } else if (fileHead.startsWith("52617221")) { return "rar"; } else { return "data"; } } }