Android开发工具类之FileUtils，ImageUtils

文件工具类，可用于读写文件及对文件进行操作。如：
readFile(String filePath) 读文件
writeFile(String filePath, String content, boolean append) 写文件
getFileSize(String path) 得到文件大小
deleteFile(String path) 删除文件

 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;

import android.text.TextUtils;

/**
 * File Utils
 * 

 * Read or write file
 * 
{@link #readFile(String, String)} read file
 * 
{@link #readFileToList(String, String)} read file to string list
 * 
{@link #writeFile(String, String, boolean)} write file from String
 * 
{@link #writeFile(String, String)} write file from String
 * 
{@link #writeFile(String, List, boolean)} write file from String List
 * 
{@link #writeFile(String, List)} write file from String List
 * 
{@link #writeFile(String, InputStream)} write file
 * 
{@link #writeFile(String, InputStream, boolean)} write file
 * 
{@link #writeFile(File, InputStream)} write file
 * 
{@link #writeFile(File, InputStream, boolean)} write file
 * 
 * 

 * Operate file
 * 
{@link #moveFile(File, File)} or {@link #moveFile(String, String)}
 * 
{@link #copyFile(String, String)}
 * 
{@link #getFileExtension(String)}
 * 
{@link #getFileName(String)}
 * 
{@link #getFileNameWithoutExtension(String)}
 * 
{@link #getFileSize(String)}
 * 
{@link #deleteFile(String)}
 * 
{@link #isFileExist(String)}
 * 
{@link #isFolderExist(String)}
 * 
{@link #makeFolders(String)}
 * 
{@link #makeDirs(String)}
 * 
 */
public class FileUtils {

    public final static String FILE_EXTENSION_SEPARATOR = ".";

    private FileUtils() {
        throw new AssertionError();
    }

    /**
     * read file
     * 
     * @param filePath
     * @param charsetName The name of a supported {@link java.nio.charset.Charset charset}
     * @return if file not exist, return null, else return content of file
     * @throws RuntimeException if an error occurs while operator BufferedReader
     */
    public static StringBuilder readFile(String filePath, String charsetName) {
        File file = new File(filePath);
        StringBuilder fileContent = new StringBuilder("");
        if (file == null || !file.isFile()) {
            return null;
        }

        BufferedReader reader = null;
        try {
            InputStreamReader is = new InputStreamReader(new FileInputStream(file), charsetName);
            reader = new BufferedReader(is);
            String line = null;
            while ((line = reader.readLine()) != null) {
                if (!fileContent.toString().equals("")) {
                    fileContent.append("\r\n");
                }
                fileContent.append(line);
            }
            return fileContent;
        } catch (IOException e) {
            throw new RuntimeException("IOException occurred. ", e);
        } finally {
            IOUtils.close(reader);
        }
    }

    /**
     * write file
     * 
     * @param filePath
     * @param content
     * @param append is append, if true, write to the end of file, else clear content of file and write into it
     * @return return false if content is empty, true otherwise
     * @throws RuntimeException if an error occurs while operator FileWriter
     */
    public static boolean writeFile(String filePath, String content, boolean append) {
        if (StringUtils.isEmpty(content)) {
            return false;
        }

        FileWriter fileWriter = null;
        try {
            makeDirs(filePath);
            fileWriter = new FileWriter(filePath, append);
            fileWriter.write(content);
            return true;
        } catch (IOException e) {
            throw new RuntimeException("IOException occurred. ", e);
        } finally {
            IOUtils.close(fileWriter);
        }
    }

    /**
     * write file
     * 
     * @param filePath
     * @param contentList
     * @param append is append, if true, write to the end of file, else clear content of file and write into it
     * @return return false if contentList is empty, true otherwise
     * @throws RuntimeException if an error occurs while operator FileWriter
     */
    public static boolean writeFile(String filePath, List contentList, boolean append) {
        if (ListUtils.isEmpty(contentList)) {
            return false;
        }

        FileWriter fileWriter = null;
        try {
            makeDirs(filePath);
            fileWriter = new FileWriter(filePath, append);
            int i = 0;
            for (String line : contentList) {
                if (i++ > 0) {
                    fileWriter.write("\r\n");
                }
                fileWriter.write(line);
            }
            return true;
        } catch (IOException e) {
            throw new RuntimeException("IOException occurred. ", e);
        } finally {
            IOUtils.close(fileWriter);
        }
    }

    /**
     * write file, the string will be written to the begin of the file
     * 
     * @param filePath
     * @param content
     * @return
     */
    public static boolean writeFile(String filePath, String content) {
        return writeFile(filePath, content, false);
    }

    /**
     * write file, the string list will be written to the begin of the file
     * 
     * @param filePath
     * @param contentList
     * @return
     */
    public static boolean writeFile(String filePath, List contentList) {
        return writeFile(filePath, contentList, false);
    }

    /**
     * write file, the bytes will be written to the begin of the file
     * 
     * @param filePath
     * @param stream
     * @return
     * @see {@link #writeFile(String, InputStream, boolean)}
     */
    public static boolean writeFile(String filePath, InputStream stream) {
        return writeFile(filePath, stream, false);
    }

    /**
     * write file
     * 
     * @param file the file to be opened for writing.
     * @param stream the input stream
     * @param append if true, then bytes will be written to the end of the file rather than the beginning
     * @return return true
     * @throws RuntimeException if an error occurs while operator FileOutputStream
     */
    public static boolean writeFile(String filePath, InputStream stream, boolean append) {
        return writeFile(filePath != null ? new File(filePath) : null, stream, append);
    }

    /**
     * write file, the bytes will be written to the begin of the file
     * 
     * @param file
     * @param stream
     * @return
     * @see {@link #writeFile(File, InputStream, boolean)}
     */
    public static boolean writeFile(File file, InputStream stream) {
        return writeFile(file, stream, false);
    }

    /**
     * write file
     * 
     * @param file the file to be opened for writing.
     * @param stream the input stream
     * @param append if true, then bytes will be written to the end of the file rather than the beginning
     * @return return true
     * @throws RuntimeException if an error occurs while operator FileOutputStream
     */
    public static boolean writeFile(File file, InputStream stream, boolean append) {
        OutputStream o = null;
        try {
            makeDirs(file.getAbsolutePath());
            o = new FileOutputStream(file, append);
            byte data[] = new byte[1024];
            int length = -1;
            while ((length = stream.read(data)) != -1) {
                o.write(data, 0, length);
            }
            o.flush();
            return true;
        } catch (FileNotFoundException e) {
            throw new RuntimeException("FileNotFoundException occurred. ", e);
        } catch (IOException e) {
            throw new RuntimeException("IOException occurred. ", e);
        } finally {
            IOUtils.close(o);
            IOUtils.close(stream);
        }
    }

    /**
     * move file
     * 
     * @param sourceFilePath
     * @param destFilePath
     */
    public static void moveFile(String sourceFilePath, String destFilePath) {
        if (TextUtils.isEmpty(sourceFilePath) || TextUtils.isEmpty(destFilePath)) {
            throw new RuntimeException("Both sourceFilePath and destFilePath cannot be null.");
        }
        moveFile(new File(sourceFilePath), new File(destFilePath));
    }

    /**
     * move file
     * 
     * @param srcFile
     * @param destFile
     */
    public static void moveFile(File srcFile, File destFile) {
        boolean rename = srcFile.renameTo(destFile);
        if (!rename) {
            copyFile(srcFile.getAbsolutePath(), destFile.getAbsolutePath());
            deleteFile(srcFile.getAbsolutePath());
        }
    }

    /**
     * copy file
     * 
     * @param sourceFilePath
     * @param destFilePath
     * @return
     * @throws RuntimeException if an error occurs while operator FileOutputStream
     */
    public static boolean copyFile(String sourceFilePath, String destFilePath) {
        InputStream inputStream = null;
        try {
            inputStream = new FileInputStream(sourceFilePath);
        } catch (FileNotFoundException e) {
            throw new RuntimeException("FileNotFoundException occurred. ", e);
        }
        return writeFile(destFilePath, inputStream);
    }

    /**
     * read file to string list, a element of list is a line
     * 
     * @param filePath
     * @param charsetName The name of a supported {@link java.nio.charset.Charset charset}
     * @return if file not exist, return null, else return content of file
     * @throws RuntimeException if an error occurs while operator BufferedReader
     */
    public static List readFileToList(String filePath, String charsetName) {
        File file = new File(filePath);
        List fileContent = new ArrayList();
        if (file == null || !file.isFile()) {
            return null;
        }

        BufferedReader reader = null;
        try {
            InputStreamReader is = new InputStreamReader(new FileInputStream(file), charsetName);
            reader = new BufferedReader(is);
            String line = null;
            while ((line = reader.readLine()) != null) {
                fileContent.add(line);
            }
            return fileContent;
        } catch (IOException e) {
            throw new RuntimeException("IOException occurred. ", e);
        } finally {
            IOUtils.close(reader);
        }
    }

    /**
     * get file name from path, not include suffix
     * 
     * 
     *      getFileNameWithoutExtension(null)               =   null
     *      getFileNameWithoutExtension("")                 =   ""
     *      getFileNameWithoutExtension("   ")              =   "   "
     *      getFileNameWithoutExtension("abc")              =   "abc"
     *      getFileNameWithoutExtension("a.mp3")            =   "a"
     *      getFileNameWithoutExtension("a.b.rmvb")         =   "a.b"
     *      getFileNameWithoutExtension("c:\\")              =   ""
     *      getFileNameWithoutExtension("c:\\a")             =   "a"
     *      getFileNameWithoutExtension("c:\\a.b")           =   "a"
     *      getFileNameWithoutExtension("c:a.txt\\a")        =   "a"
     *      getFileNameWithoutExtension("/home/admin")      =   "admin"
     *      getFileNameWithoutExtension("/home/admin/a.txt/b.mp3")  =   "b"
     * 
     * 
     * @param filePath
     * @return file name from path, not include suffix
     * @see
     */
    public static String getFileNameWithoutExtension(String filePath) {
        if (StringUtils.isEmpty(filePath)) {
            return filePath;
        }

        int extenPosi = filePath.lastIndexOf(FILE_EXTENSION_SEPARATOR);
        int filePosi = filePath.lastIndexOf(File.separator);
        if (filePosi == -1) {
            return (extenPosi == -1 ? filePath : filePath.substring(0, extenPosi));
        }
        if (extenPosi == -1) {
            return filePath.substring(filePosi + 1);
        }
        return (filePosi < extenPosi ? filePath.substring(filePosi + 1, extenPosi) : filePath.substring(filePosi + 1));
    }

    /**
     * get file name from path, include suffix
     * 
     * 
     *      getFileName(null)               =   null
     *      getFileName("")                 =   ""
     *      getFileName("   ")              =   "   "
     *      getFileName("a.mp3")            =   "a.mp3"
     *      getFileName("a.b.rmvb")         =   "a.b.rmvb"
     *      getFileName("abc")              =   "abc"
     *      getFileName("c:\\")              =   ""
     *      getFileName("c:\\a")             =   "a"
     *      getFileName("c:\\a.b")           =   "a.b"
     *      getFileName("c:a.txt\\a")        =   "a"
     *      getFileName("/home/admin")      =   "admin"
     *      getFileName("/home/admin/a.txt/b.mp3")  =   "b.mp3"
     * 
     * 
     * @param filePath
     * @return file name from path, include suffix
     */
    public static String getFileName(String filePath) {
        if (StringUtils.isEmpty(filePath)) {
            return filePath;
        }

        int filePosi = filePath.lastIndexOf(File.separator);
        return (filePosi == -1) ? filePath : filePath.substring(filePosi + 1);
    }

    /**
     * get folder name from path
     * 
     * 
     *      getFolderName(null)               =   null
     *      getFolderName("")                 =   ""
     *      getFolderName("   ")              =   ""
     *      getFolderName("a.mp3")            =   ""
     *      getFolderName("a.b.rmvb")         =   ""
     *      getFolderName("abc")              =   ""
     *      getFolderName("c:\\")              =   "c:"
     *      getFolderName("c:\\a")             =   "c:"
     *      getFolderName("c:\\a.b")           =   "c:"
     *      getFolderName("c:a.txt\\a")        =   "c:a.txt"
     *      getFolderName("c:a\\b\\c\\d.txt")    =   "c:a\\b\\c"
     *      getFolderName("/home/admin")      =   "/home"
     *      getFolderName("/home/admin/a.txt/b.mp3")  =   "/home/admin/a.txt"
     * 
     * 
     * @param filePath
     * @return
     */
    public static String getFolderName(String filePath) {

        if (StringUtils.isEmpty(filePath)) {
            return filePath;
        }

        int filePosi = filePath.lastIndexOf(File.separator);
        return (filePosi == -1) ? "" : filePath.substring(0, filePosi);
    }

    /**
     * get suffix of file from path
     * 
     * 
     *      getFileExtension(null)               =   ""
     *      getFileExtension("")                 =   ""
     *      getFileExtension("   ")              =   "   "
     *      getFileExtension("a.mp3")            =   "mp3"
     *      getFileExtension("a.b.rmvb")         =   "rmvb"
     *      getFileExtension("abc")              =   ""
     *      getFileExtension("c:\\")              =   ""
     *      getFileExtension("c:\\a")             =   ""
     *      getFileExtension("c:\\a.b")           =   "b"
     *      getFileExtension("c:a.txt\\a")        =   ""
     *      getFileExtension("/home/admin")      =   ""
     *      getFileExtension("/home/admin/a.txt/b")  =   ""
     *      getFileExtension("/home/admin/a.txt/b.mp3")  =   "mp3"
     * 
     * 
     * @param filePath
     * @return
     */
    public static String getFileExtension(String filePath) {
        if (StringUtils.isBlank(filePath)) {
            return filePath;
        }

        int extenPosi = filePath.lastIndexOf(FILE_EXTENSION_SEPARATOR);
        int filePosi = filePath.lastIndexOf(File.separator);
        if (extenPosi == -1) {
            return "";
        }
        return (filePosi >= extenPosi) ? "" : filePath.substring(extenPosi + 1);
    }

    /**
     * Creates the directory named by the trailing filename of this file, including the complete directory path required
     * to create this directory. 

     * 

     * 

     * Attentions:
     * 
makeDirs("C:\\Users\\Trinea") can only create users folder
     * 
makeFolder("C:\\Users\\Trinea\\") can create Trinea folder
     * 
     * 
     * @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.
     *         

     *         
if {@link FileUtils#getFolderName(String)} return null, return false
     *         
if target directory already exists, return true
     *         
return {@link java.io.File#makeFolder}
     *         
     */
    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
     * 

     * 
if path is null or empty, return true
     * 
if path not exist, return true
     * 
if path exist, delete recursion. return true
     * 

     * 
     * @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
     * 

     * 
if path is null or empty, return -1
     * 
if path exist and it is a file, return file size, else return -1
     * 

     * 
     * @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);
    }
}   

ImageUtils

图片工具类，可用于Bitmap, byte array, Drawable之间进行转换以及图片缩放，目前功能薄弱，后面会进行增强。如：
bitmapToDrawable(Bitmap b) bimap转换为drawable
drawableToBitmap(Drawable d) drawable转换为bitmap
drawableToByte(Drawable d) drawable转换为byte
scaleImage(Bitmap org, float scaleWidth, float scaleHeight) 缩放图片

 import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.Map;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Matrix;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;

/**
 * ImageUtils
 * 

 * convert between Bitmap, byte array, Drawable
 * 
{@link #bitmapToByte(Bitmap)}
 * 
{@link #bitmapToDrawable(Bitmap)}
 * 
{@link #byteToBitmap(byte[])}
 * 
{@link #byteToDrawable(byte[])}
 * 
{@link #drawableToBitmap(Drawable)}
 * 
{@link #drawableToByte(Drawable)}
 * 
 * 

 * get image
 * 
{@link #getInputStreamFromUrl(String, int)}
 * 
{@link #getBitmapFromUrl(String, int)}
 * 
{@link #getDrawableFromUrl(String, int)}
 * 
 * 

 * scale image
 * 
{@link #scaleImageTo(Bitmap, int, int)}
 * 
{@link #scaleImage(Bitmap, float, float)}
 * 
 */
public class ImageUtils {

    private ImageUtils() {
        throw new AssertionError();
    }

    /**
     * convert Bitmap to byte array
     * 
     * @param b
     * @return
     */
    public static byte[] bitmapToByte(Bitmap b) {
        if (b == null) {
            return null;
        }

        ByteArrayOutputStream o = new ByteArrayOutputStream();
        b.compress(Bitmap.CompressFormat.PNG, 100, o);
        return o.toByteArray();
    }

    /**
     * convert byte array to Bitmap
     * 
     * @param b
     * @return
     */
    public static Bitmap byteToBitmap(byte[] b) {
        return (b == null || b.length == 0) ? null : BitmapFactory.decodeByteArray(b, 0, b.length);
    }

    /**
     * convert Drawable to Bitmap
     * 
     * @param d
     * @return
     */
    public static Bitmap drawableToBitmap(Drawable d) {
        return d == null ? null : ((BitmapDrawable)d).getBitmap();
    }

    /**
     * convert Bitmap to Drawable
     * 
     * @param b
     * @return
     */
    public static Drawable bitmapToDrawable(Bitmap b) {
        return b == null ? null : new BitmapDrawable(b);
    }

    /**
     * convert Drawable to byte array
     * 
     * @param d
     * @return
     */
    public static byte[] drawableToByte(Drawable d) {
        return bitmapToByte(drawableToBitmap(d));
    }

    /**
     * convert byte array to Drawable
     * 
     * @param b
     * @return
     */
    public static Drawable byteToDrawable(byte[] b) {
        return bitmapToDrawable(byteToBitmap(b));
    }

    /**
     * get input stream from network by imageurl, you need to close inputStream yourself
     * 
     * @param imageUrl
     * @param readTimeOutMillis
     * @return
     * @see ImageUtils#getInputStreamFromUrl(String, int, boolean)
     */
    public static InputStream getInputStreamFromUrl(String imageUrl, int readTimeOutMillis) {
        return getInputStreamFromUrl(imageUrl, readTimeOutMillis, null);
    }

    /**
     * get input stream from network by imageurl, you need to close inputStream yourself
     * 
     * @param imageUrl
     * @param readTimeOutMillis read time out, if less than 0, not set, in mills
     * @param requestProperties http request properties
     * @return
     * @throws MalformedURLException
     * @throws IOException
     */
    public static InputStream getInputStreamFromUrl(String imageUrl, int readTimeOutMillis,
            Map requestProperties) {
        InputStream stream = null;
        try {
            URL url = new URL(imageUrl);
            HttpURLConnection con = (HttpURLConnection)url.openConnection();
            HttpUtils.setURLConnection(requestProperties, con);
            if (readTimeOutMillis > 0) {
                con.setReadTimeout(readTimeOutMillis);
            }
            stream = con.getInputStream();
        } catch (MalformedURLException e) {
            IOUtils.close(stream);
            throw new RuntimeException("MalformedURLException occurred. ", e);
        } catch (IOException e) {
            IOUtils.close(stream);
            throw new RuntimeException("IOException occurred. ", e);
        }
        return stream;
    }

    /**
     * get drawable by imageUrl
     * 
     * @param imageUrl
     * @param readTimeOutMillis
     * @return
     * @see ImageUtils#getDrawableFromUrl(String, int, boolean)
     */
    public static Drawable getDrawableFromUrl(String imageUrl, int readTimeOutMillis) {
        return getDrawableFromUrl(imageUrl, readTimeOutMillis, null);
    }

    /**
     * get drawable by imageUrl
     * 
     * @param imageUrl
     * @param readTimeOutMillis read time out, if less than 0, not set, in mills
     * @param requestProperties http request properties
     * @return
     */
    public static Drawable getDrawableFromUrl(String imageUrl, int readTimeOutMillis,
            Map requestProperties) {
        InputStream stream = getInputStreamFromUrl(imageUrl, readTimeOutMillis, requestProperties);
        Drawable d = Drawable.createFromStream(stream, "src");
        IOUtils.close(stream);
        return d;
    }

    /**
     * get Bitmap by imageUrl
     * 
     * @param imageUrl
     * @param readTimeOut
     * @return
     * @see ImageUtils#getBitmapFromUrl(String, int, boolean)
     */
    public static Bitmap getBitmapFromUrl(String imageUrl, int readTimeOut) {
        return getBitmapFromUrl(imageUrl, readTimeOut, null);
    }

    /**
     * get Bitmap by imageUrl
     * 
     * @param imageUrl
     * @param requestProperties http request properties
     * @return
     */
    public static Bitmap getBitmapFromUrl(String imageUrl, int readTimeOut, Map requestProperties) {
        InputStream stream = getInputStreamFromUrl(imageUrl, readTimeOut, requestProperties);
        Bitmap b = BitmapFactory.decodeStream(stream);
        IOUtils.close(stream);
        return b;
    }

    /**
     * scale image
     * 
     * @param org
     * @param newWidth
     * @param newHeight
     * @return
     */
    public static Bitmap scaleImageTo(Bitmap org, int newWidth, int newHeight) {
        return scaleImage(org, (float) newWidth / org.getWidth(), (float) newHeight / org.getHeight());
    }

    /**
     * scale image
     * 
     * @param org
     * @param scaleWidth sacle of width
     * @param scaleHeight scale of height
     * @return
     */
    public static Bitmap scaleImage(Bitmap org, float scaleWidth, float scaleHeight) {
        if (org == null) {
            return null;
        }

        Matrix matrix = new Matrix();
        matrix.postScale(scaleWidth, scaleHeight);
        return Bitmap.createBitmap(org, 0, 0, org.getWidth(), org.getHeight(), matrix, true);
    }

}