本文实例讲述了Android中Java根据文件头获取文件类型的方法。分享给大家供大家参考,具体如下:
前面讲过Android系统内部的MediaFile类来获取文件类型的办法,这个类主要是根据文件的扩展名来判断,其准确性不是很好。具体可查看Android系统使用MediaFile类判断音频文件类型。其实,获取文件类型最好的办法便是根据文件头信息来判断。下面贴出相关代码:
public class FileType { public static final HashMap<String,String> mFileTypes = new HashMap<String,String>(); static { //images mFileTypes.put("FFD8FF","jpg"); mFileTypes.put("89504E47","png"); mFileTypes.put("47494638","gif"); mFileTypes.put("49492A00","tif"); mFileTypes.put("424D","bmp"); // mFileTypes.put("41433130","dwg"); //CAD mFileTypes.put("38425053","psd"); mFileTypes.put("7B5C727466","rtf"); //日记本 mFileTypes.put("3C3F786D6C","xml"); mFileTypes.put("68746D6C3E","html"); mFileTypes.put("44656C69766572792D646174653A","eml"); //邮件 mFileTypes.put("D0CF11E0","doc"); mFileTypes.put("5374616E64617264204A","mdb"); mFileTypes.put("252150532D41646F6265","ps"); mFileTypes.put("255044462D312E","pdf"); mFileTypes.put("504B0304","zip"); mFileTypes.put("52617221","rar"); mFileTypes.put("57415645","wav"); mFileTypes.put("41564920","avi"); mFileTypes.put("2E524D46","rm"); mFileTypes.put("000001BA","mpg"); mFileTypes.put("000001B3","mpg"); mFileTypes.put("6D6F6F76","mov"); mFileTypes.put("3026B2758E66CF11","asf"); mFileTypes.put("4D546864","mid"); mFileTypes.put("1F8B08","gz"); mFileTypes.put("",""); mFileTypes.put("",""); } public static String getFileType(String filePath) { return mFileTypes.get(getFileHeader(filePath)); } //获取文件头信息 public static String getFileHeader(String filePath) { FileInputStream is = null; String value = null; try { is = new FileInputStream(filePath); byte[] b = new byte[3]; is.read(b,b.length); value = bytesToHexString(b); } catch (Exception e) { } finally { if(null != is) { try { is.close(); } catch (IOException e) {} } } return value; } private static String bytesToHexString(byte[] src){ StringBuilder builder = new StringBuilder(); if (src == null || src.length <= 0) { return null; } String hv; for (int i = 0; i < src.length; i++) { hv = Integer.toHexString(src[i] & 0xFF).toupperCase(); if (hv.length() < 2) { builder.append(0); } builder.append(hv); } return builder.toString(); } public static void main(String[] args) throws Exception { final String fileType = getFileType("D:/apache-tomcat-6.0.35.tar.gz"); System.out.println(fileType); } }
更多关于Android相关内容感兴趣的读者可查看本站专题:《Android开发入门与进阶教程》、《Android多媒体操作技巧汇总(音频,视频,录音等)》、《Android基本组件用法总结》、《Android视图View技巧总结》、《Android布局layout技巧总结》及《Android控件用法总结》
希望本文所述对大家Android程序设计有所帮助。