JAVA文件/文件夹操作实用函数

列举了一些这个项目中用到的文件/文件夹操作的函数，以备后用。

/**
* 计算文件夹大小
*/
public static final long getDirectorySize( File dir ) {
    long retSize = 0;
    if ( ( dir == null ) || !dir.isDirectory() ) {
        return retSize;
    }
    File[] entries = dir.listFiles();
    int count = entries.length;
    for ( int i = 0; i < count; i++ ) {
        if ( entries[ i ].isDirectory() ) {
            retSize += getDirectorySize( entries[ i ] );
        } else {
            retSize += entries[ i ].length();
        }
    }
    return retSize;
}  

/**
* 删除文件夹
*/
public static final boolean deleteDirectory( File dir ) {
    boolean bRet = false;
    if ( dir !=null && dir.isDirectory() ) {
        File[] entries = dir.listFiles();
        int sz = entries.length;
        for ( int i = 0; i < sz; i++ ) {
            if ( entries[ i ].isDirectory() ) {
                deleteDirectory( entries[ i ] );
            } else {
                entries[ i ].delete();
            }
        }
        dir.delete();
        bRet = true;
    }
    return bRet;
}

/**
* 新建文件夹
*/
public static final void createDirectory( String strDir ) {
    File file = new File( strDir );
    if ( !file.isDirectory() ) {
        file.mkdir();
    }
}

/**
* 移动文件
*/
public static final void moveFile( String strOriginal, String strDest ) throws IOException {
    try {
        File fileOriginal = new File( strOriginal );
        File fileDest = new File( strDest );
        fileOriginal.renameTo( fileDest );
    } catch ( IOException e ) {
        throw new IOException("");
    }
}

/**
* 复制文件
*/
public static final void copyFile( String strOriginal, String strDest ) throws IOException{
    try {
        File fileOriginal = new File( strOriginal );
        File fileDest = new File( strDest );
        FileInputStream fis = new FileInputStream( fileOriginal );
        FileOutputStream fos = new FileOutputStream( fileDest );
        byte[] bytes = new byte[ 1024 ];
        int c;
        while ( ( c = fis.read( bytes ) ) != -1 ) {
            fos.write( bytes, 0, c );
        }
        fis.close();
        fos.close();
    } catch ( IOException e ) {
        throw new IOException("");
    }
}
   
/**
* 复制文件夹
*/
public static final boolean copyDirectory( String strOriginal, String  strDest ) throws Exception {
    boolean bRet = false;
    File dirOriginal = new File( strOriginal );
    if ( dirOriginal !=null && dirOriginal.isDirectory() ) {
        createDirectory( strDest );
        File dirDest = new File( strDest );
        File[] entries = dirOriginal.listFiles();
        int sz = entries.length;
        for ( int i = 0; i < sz; i++ ) {
            StringBuffer sbDest = new StringBuffer();
            sbDest.append( dirDest.getPath() );
            sbDest.append( "\" );
            sbDest.append( entries[ i ].getName() );
            if ( entries[ i ].isDirectory() ) {
                strDest = dirDest.getPath() + "\" + entries[ i ].getName();
                copyDirectory( entries[ i ].getPath(), sbDest.toString() );
            } else {
                copyFile( entries[ i ].getPath(), sbDest.toString() );
            }
        }
        bRet = true;
    }
    return bRet;
}

/**
* 读取文件
*/
private String readFile( File file ) {
    String text= "";
    if ( file.exists() ) {
        Reader reader = null;
        try {
            char[] tempchars = new char[1024];
            int charread = 0;
            reader = new InputStreamReader( new FileInputStream( file ), "UTF-8" );
            while ( ( charread = reader.read( tempchars ) ) != -1 ) {
                for ( int i = 0; i < charread; i++ ) {
                    if ( tempchars[i] == '\r' ) {
                        continue;
                    } else {
                        text += tempchars[i];
                    }
                }
            }
            reader.close();
        } catch ( IOException e ) {
            throw new IOException("");
        }
    }
    return text;
}

/**
* 写入文件
*/
private boolean writeFile( File file, String text ) {
    try {
        Writer writer = new OutputStreamWriter( new FileOutputStream( file ), "UTF-8" );
        writer.write( text );
        writer.close();
        return true;
    } catch ( IOException e ) {
        return false;
    }
}

/**
* 文件夹中的文件按文件名排序（升序）
*/
File[]   files = ( new File( strPictureDirectory ) ).listFiles();
File temp;
for ( int i = 0; i < files.length; i++ ) {
    for ( int j = i; j < files.length; j++ ) {
        if ( files[i].getName().compareTo( files[j].getName() ) > 0 ) {
            temp = files[i];
            files[i] = files[j];
            files[j] = temp;
        }
    }
}