结合以前的项目开发中遇到的不同的文件操作，在这里基本上提取出了所遇到过的文件操作的工具类。

1 我项目中用到的文件工具类

1 读取raw文件、file文件，drawable文件，asset文件，比如本地的json数据，本地文本等；
如：String result =FileUtil.getString(context,”raw://first.json”)
2 读取本地的property文件，并转化为hashMap类型的数据 （simpleProperty2HashMap）；
3 将raw文件拷贝到指定目录（copyRawFile）；
4 基本文件读写操作（readFile，writeFile）；
5 从文件的完整路径名（路径+文件名）中提取 路径（extractFilePath）；
6 从文件的完整路径名（路径+文件名）中提取文件名(包含扩展名)
如：d:\path\file.ext –> file.ext（extractFileName）
7 检查指定文件的路径是否存在（pathExists）
8 检查制定文件是否存在（fileExists）
9 创建目录（makeDir）
10 移除字符串中的BOM前缀（removeBomHeaderIfExists）

package com.nsu.edu.library.utils;import android.content.Context;import android.graphics.Bitmap;import android.graphics.drawable.BitmapDrawable;import android.text.TextUtils;import java.io.BufferedReader;import java.io.ByteArrayInputStream;import java.io.ByteArrayOutputStream;import java.io.File;import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.IOException;import java.io.InputStream;import java.io.InputStreamReader;import java.io.OutputStream;import java.util.HashMap;import java.util.Iterator;import java.util.Properties;import java.util.Set;/** * Create By Anthony on 2016/1/15 * Class Note:文件工具类 * 包含内容： * 1 读取raw文件、file文件，drawable文件，asset文件，比如本地的json数据，本地文本等； * 如：String result =FileUtil.getString(context,"raw://first.json") * 2 读取本地的property文件，并转化为hashMap类型的数据（simpleProperty2HashMap）； * 3 将raw文件拷贝到指定目录（copyRawFile）； * 4 基本文件读写操作（readFile，writeFile）； * 5 从文件的完整路径名（路径+文件名）中提取 路径（extractFilePath）； * 6 从文件的完整路径名（路径+文件名）中提取文件名(包含扩展名) 如：d:\path\file.ext --> file.ext（extractFileName） *7 检查指定文件的路径是否存在（pathExists） *8 检查制定文件是否存在（fileExists） *9 创建目录（makeDir） *10 移除字符串中的BOM前缀（removeBomHeaderIfExists） */public class FileUtil { public static final String ASSETS_PREFIX = "file://android_assets/"; public static final String ASSETS_PREFIX2 = "file://android_asset/"; public static final String ASSETS_PREFIX3 = "assets://"; public static final String ASSETS_PREFIX4 = "asset://"; public static final String RAW_PREFIX = "file://android_raw/"; public static final String RAW_PREFIX2 = "raw://"; public static final String FILE_PREFIX = "file://"; public static final String DRAWABLE_PREFIX = "drawable://"; public static InputStream getStream(Context context, String url) throws IOException { String lowerUrl = url.toLowerCase(); InputStream is; if (lowerUrl.startsWith(ASSETS_PREFIX)) { String assetPath = url.substring(ASSETS_PREFIX.length()); is = getAssetsStream(context, assetPath); } else if (lowerUrl.startsWith(ASSETS_PREFIX2)) { String assetPath = url.substring(ASSETS_PREFIX2.length()); is = getAssetsStream(context, assetPath); } else if (lowerUrl.startsWith(ASSETS_PREFIX3)) { String assetPath = url.substring(ASSETS_PREFIX3.length()); is = getAssetsStream(context, assetPath); } else if (lowerUrl.startsWith(ASSETS_PREFIX4)) { String assetPath = url.substring(ASSETS_PREFIX4.length()); is = getAssetsStream(context, assetPath); } else if (lowerUrl.startsWith(RAW_PREFIX)) { String rawName = url.substring(RAW_PREFIX.length()); is = getRawStream(context, rawName); } else if (lowerUrl.startsWith(RAW_PREFIX2)) { String rawName = url.substring(RAW_PREFIX2.length()); is = getRawStream(context, rawName); } else if (lowerUrl.startsWith(FILE_PREFIX)) { String filePath = url.substring(FILE_PREFIX.length()); is = getFileStream(filePath); } else if (lowerUrl.startsWith(DRAWABLE_PREFIX)) { String drawableName = url.substring(DRAWABLE_PREFIX.length()); is = getDrawableStream(context, drawableName); } else { throw new IllegalArgumentException(String.format("Unsupported url: %s \n" + "Supported: \n%sxxx\n%sxxx\n%sxxx", url, ASSETS_PREFIX, RAW_PREFIX, FILE_PREFIX)); } return is; } private static InputStream getAssetsStream(Context context, String path) throws IOException { return context.getAssets().open(path); } private static InputStream getFileStream(String path) throws IOException { return new FileInputStream(path); } private static InputStream getRawStream(Context context, String rawName) throws IOException { int id = context.getResources().getIdentifier(rawName, "raw", context.getPackageName()); if (id != 0) { try { return context.getResources().openRawResource(id); } catch (Exception e) { e.printStackTrace(); } } throw new IOException(String.format("raw of id: %s from %s not found", id, rawName)); } private static InputStream getDrawableStream(Context context, String rawName) throws IOException { int id = context.getResources().getIdentifier(rawName, "drawable", context.getPackageName()); if (id != 0) { BitmapDrawable drawable = (BitmapDrawable) context.getResources().getDrawable(id); Bitmap bitmap = drawable.getBitmap(); ByteArrayOutputStream os = new ByteArrayOutputStream(); bitmap.compress(Bitmap.CompressFormat.PNG, 0, os); return new ByteArrayInputStream(os.toByteArray()); } throw new IOException(String.format("bitmap of id: %s from %s not found", id, rawName)); } public static String getString(Context context, String url) throws IOException { return getString(context, url, "UTF-8"); } public static String getString(Context context, String url, String encoding) throws IOException { String result = readStreamString(getStream(context, url), encoding); if (result.startsWith("\ufeff")) { result = result.substring(1); } return result; } public static String readStreamString(InputStream is, String encoding) throws IOException { return new String(readStream(is), encoding); } public static byte[] readStream(InputStream is) throws IOException { ByteArrayOutputStream baos = new ByteArrayOutputStream(); byte[] buf = new byte[1024 * 10]; int readlen; while ((readlen = is.read(buf)) >= 0) { baos.write(buf, 0, readlen); } baos.close(); return baos.toByteArray(); } public static Bitmap getDrawableBitmap(Context context, String rawName) { int id = context.getResources().getIdentifier(rawName, "drawable", context.getPackageName()); if (id != 0) { BitmapDrawable drawable = (BitmapDrawable) context.getResources().getDrawable(id); if (drawable != null) { return drawable.getBitmap(); } } return null; } /** * 读取Property文件 */ public static HashMap<String, String> simpleProperty2HashMap(Context context, String path) { try { InputStream is = getStream(context, path); return simpleProperty2HashMap(is); } catch (IOException e) { e.printStackTrace(); } return new HashMap<String, String>(); } private static HashMap<String, String> simpleProperty2HashMap(InputStream in) throws IOException { HashMap<String, String> hashMap = new HashMap<String, String>(); Properties properties = new Properties(); properties.load(in); in.close(); Set keyValue = properties.keySet(); for (Iterator it = keyValue.iterator(); it.hasNext(); ) { String key = (String) it.next(); hashMap.put(key, (String) properties.get(key)); } return hashMap; } /** * 将raw文件拷贝到指定目录 */ public static void copyRawFile(Context ctx, String rawFileName, String to) { String[] names = rawFileName.split("\\."); String toFile = to + "/" + names[0] + "." + names[1]; File file = new File(toFile); if (file.exists()) { return; } try { InputStream is = getStream(ctx, "raw://" + names[0]); OutputStream os = new FileOutputStream(toFile); int byteCount = 0; byte[] bytes = new byte[1024]; while ((byteCount = is.read(bytes)) != -1) { os.write(bytes, 0, byteCount); } os.close(); is.close(); } catch (Exception e) { e.printStackTrace(); } } /** * 基本文件操作 */ public static String FILE_READING_ENCODING = "UTF-8"; public static String FILE_WRITING_ENCODING = "UTF-8"; public static String readFile(String _sFileName, String _sEncoding) throws Exception { StringBuffer buffContent = null; String sLine; FileInputStream fis = null; BufferedReader buffReader = null; if (_sEncoding == null || "".equals(_sEncoding)) { _sEncoding = FILE_READING_ENCODING; } try { fis = new FileInputStream(_sFileName); buffReader = new BufferedReader(new InputStreamReader(fis, _sEncoding)); boolean zFirstLine = "UTF-8".equalsIgnoreCase(_sEncoding); while ((sLine = buffReader.readLine()) != null) { if (buffContent == null) { buffContent = new StringBuffer(); } else { buffContent.append("\n"); } if (zFirstLine) { sLine = removeBomHeaderIfExists(sLine); zFirstLine = false; } buffContent.append(sLine); }// end while return (buffContent == null ? "" : buffContent.toString()); } catch (FileNotFoundException ex) { throw new Exception("要读取的文件没有找到!", ex); } catch (IOException ex) { throw new Exception("读取文件时错误!", ex); } finally { // 增加异常时资源的释放 try { if (buffReader != null) buffReader.close(); if (fis != null) fis.close(); } catch (Exception ex) { ex.printStackTrace(); } } } public static File writeFile(InputStream is, String path, boolean isOverride) throws Exception { String sPath = extractFilePath(path); if (!pathExists(sPath)) { makeDir(sPath, true); } if (!isOverride && fileExists(path)) { if(path.contains(".")) { String suffix = path.substring(path.lastIndexOf(".")); String pre = path.substring(0, path.lastIndexOf(".")); path = pre + "_" + TimeUtils.getNowTime() + suffix; } else { path = path + "_" + TimeUtils.getNowTime(); } } FileOutputStream os = null; File file = null; try { file = new File(path); os = new FileOutputStream(file); int byteCount = 0; byte[] bytes = new byte[1024]; while ((byteCount = is.read(bytes)) != -1) { os.write(bytes, 0, byteCount); } os.flush(); return file; } catch (Exception e) { e.printStackTrace(); throw new Exception("写文件错误", e); } finally { try { if (os != null) os.close(); if (is != null) is.close(); } catch (Exception e) { e.printStackTrace(); } } } public static File writeFile(String path, String content, String encoding, boolean isOverride) throws Exception { if (TextUtils.isEmpty(encoding)) { encoding = FILE_WRITING_ENCODING; } InputStream is = new ByteArrayInputStream(content.getBytes(encoding)); return writeFile(is, path, isOverride); } /** * 从文件的完整路径名（路径+文件名）中提取 路径（包括：Drive+Directroy ) * * @param _sFilePathName * @return */ public static String extractFilePath(String _sFilePathName) { int nPos = _sFilePathName.lastIndexOf('/'); if (nPos < 0) { nPos = _sFilePathName.lastIndexOf('\\'); } return (nPos >= 0 ? _sFilePathName.substring(0, nPos + 1) : ""); } /** * 从文件的完整路径名（路径+文件名）中提取文件名(包含扩展名) <br> * 如：d:\path\file.ext --> file.ext * * @param _sFilePathName * @return */ public static String extractFileName(String _sFilePathName) { return extractFileName(_sFilePathName, File.separator); } /** * 从文件的完整路径名（路径+文件名）中提取文件名(包含扩展名) <br> * 如：d:\path\file.ext --> file.ext * * @param _sFilePathName 全文件路径名 * @param _sFileSeparator 文件分隔符 * @return */ public static String extractFileName(String _sFilePathName, String _sFileSeparator) { int nPos = -1; if (_sFileSeparator == null) { nPos = _sFilePathName.lastIndexOf(File.separatorChar); if (nPos < 0) { nPos = _sFilePathName .lastIndexOf(File.separatorChar == '/' ? '\\' : '/'); } } else { nPos = _sFilePathName.lastIndexOf(_sFileSeparator); } if (nPos < 0) { return _sFilePathName; } return _sFilePathName.substring(nPos + 1); } /** * 检查指定文件的路径是否存在 * * @param _sPathFileName 文件名称(含路径） * @return 若存在，则返回true；否则，返回false */ public static boolean pathExists(String _sPathFileName) { String sPath = extractFilePath(_sPathFileName); return fileExists(sPath); } public static boolean fileExists(String _sPathFileName) { File file = new File(_sPathFileName); return file.exists(); } /** * 创建目录 * * @param _sDir 目录名称 * @param _bCreateParentDir 如果父目录不存在，是否创建父目录 * @return */ public static boolean makeDir(String _sDir, boolean _bCreateParentDir) { boolean zResult = false; File file = new File(_sDir); if (_bCreateParentDir) zResult = file.mkdirs(); // 如果父目录不存在，则创建所有必需的父目录 else zResult = file.mkdir(); // 如果父目录不存在，不做处理 if (!zResult) zResult = file.exists(); return zResult; } /** * 移除字符串中的BOM前缀 * * @param _sLine 需要处理的字符串 * @return 移除BOM后的字符串. */ private static String removeBomHeaderIfExists(String _sLine) { if (_sLine == null) { return null; } String line = _sLine; if (line.length() > 0) { char ch = line.charAt(0); // 使用while是因为用一些工具看到过某些文件前几个字节都是0xfffe. // 0xfeff,0xfffe是字节序的不同处理.JVM中,一般是0xfeff while ((ch == 0xfeff || ch == 0xfffe)) { line = line.substring(1); if (line.length() == 0) { break; } ch = line.charAt(0); } } return line; }}

2 网上的工具类

这个工具类也大同小异。其中也有很多和我上面重复的一些方法，也有上面没有的方法。转自Trinea的android-common项目。这里直接贴出来，不做任何更改。希望能对看到的人有帮助。也做一个笔记。

package com.nsu.edu.library.utils;import android.text.TextUtils;import java.io.BufferedReader;import java.io.File;import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.FileWriter;import java.io.IOException;import java.io.InputStream;import java.io.InputStreamReader;import java.io.OutputStream;import java.util.ArrayList;import java.util.List;/** * File Utils * <ul> * Read or write file * <li>{@link #readFile(String, String)} read file</li> * <li>{@link #readFileToList(String, String)} read file to string list</li> * <li>{@link #writeFile(String, String, boolean)} write file from String</li> * <li>{@link #writeFile(String, String)} write file from String</li> * <li>{@link #writeFile(String, List, boolean)} write file from String List</li> * <li>{@link #writeFile(String, List)} write file from String List</li> * <li>{@link #writeFile(String, InputStream)} write file</li> * <li>{@link #writeFile(String, InputStream, boolean)} write file</li> * <li>{@link #writeFile(File, InputStream)} write file</li> * <li>{@link #writeFile(File, InputStream, boolean)} write file</li> * </ul> * <ul> * Operate file * <li>{@link #moveFile(File, File)} or {@link #moveFile(String, String)}</li> * <li>{@link #copyFile(String, String)}</li> * <li>{@link #getFileExtension(String)}</li> * <li>{@link #getFileName(String)}</li> * <li>{@link #getFileNameWithoutExtension(String)}</li> * <li>{@link #getFileSize(String)}</li> * <li>{@link #deleteFile(String)}</li> * <li>{@link #isFileExist(String)}</li> * <li>{@link #isFolderExist(String)}</li> * <li>{@link #makeFolders(String)}</li> * <li>{@link #makeDirs(String)}</li> * </ul> * * @author <a href="http://plete directory path required * to create this directory. <br/> * <br/> * <ul> * <strong>Attentions:</strong> * <li>makeDirs("C:\\Users\\Trinea") can only create users folder</li> * <li>makeFolder("C:\\Users\\Trinea\\") can create Trinea folder</li> * </ul> * * @param filePath * @return true if the necessary directories have been created or the target directory already exists, false one of * the directories can not be created. * <ul> * <li>if {@link FileUtils#getFolderName(String)} return null, return false</li> * <li>if target directory already exists, return true</li> * <li>return {@link File#makeFolder}</li> * </ul> */ public static boolean makeDirs(String filePath) { String folderName = getFolderName(filePath); if (StringUtils.isEmpty(folderName)) { return false; } File folder = new File(folderName); return (folder.exists() && folder.isDirectory()) ? true : folder.mkdirs(); } /** * @param filePath * @return * @see #makeDirs(String) */ public static boolean makeFolders(String filePath) { return makeDirs(filePath); } /** * Indicates if this file represents a file on the underlying file system. * * @param filePath * @return */ public static boolean isFileExist(String filePath) { if (StringUtils.isBlank(filePath)) { return false; } File file = new File(filePath); return (file.exists() && file.isFile()); } /** * Indicates if this file represents a directory on the underlying file system. * * @param directoryPath * @return */ public static boolean isFolderExist(String directoryPath) { if (StringUtils.isBlank(directoryPath)) { return false; } File dire = new File(directoryPath); return (dire.exists() && dire.isDirectory()); } /** * delete file or directory * <ul> * <li>if path is null or empty, return true</li> * <li>if path not exist, return true</li> * <li>if path exist, delete recursion. return true</li> * <ul> * * @param path * @return */ public static boolean deleteFile(String path) { if (StringUtils.isBlank(path)) { return true; } File file = new File(path); if (!file.exists()) { return true; } if (file.isFile()) { return file.delete(); } if (!file.isDirectory()) { return false; } for (File f : file.listFiles()) { if (f.isFile()) { f.delete(); } else if (f.isDirectory()) { deleteFile(f.getAbsolutePath()); } } return file.delete(); } /** * get file size * <ul> * <li>if path is null or empty, return -1</li> * <li>if path exist and it is a file, return file size, else return -1</li> * <ul> * * @param path * @return returns the length of this file in bytes. returns -1 if the file does not exist. */ public static long getFileSize(String path) { if (StringUtils.isBlank(path)) { return -1; } File file = new File(path); return (file.exists() && file.isFile() ? file.length() : -1); }}

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