OC-NSFileManager和NSFileHandle的使用

@interface ReplaceStringInDirectory : NSObject
/**
 *  替换指定文件中指定的所有字符串为另一个字符串
 */
+ (void)replaceInDirectory:(NSString *)pathFile withOldString:(NSString *)oldString withNewString:(NSString *)newString;

//替换指定目录下所有指定类型的文件中的字符串
+ (void)replaceInDirectory:(NSString *)pathDirectory withOldString:(NSString *)oldString withNewString:(NSString *)newString InType:(NSString *)typeFile;
@end

/**
 *  替换指定文件中指定的所有字符串为另一个字符串
 */
+ (void)replaceInDirectory:(NSString *)pathFile withOldString:(NSString *)oldString withNewString:(NSString *)newString
{
    //文件目录管理器 一个单例对象
    NSFileManager *fm = [NSFileManager defaultManager];
    //先备份一份文件在相同的路劲下，并以指定文件格式
    [fm copyItemAtPath:pathFile toPath:[pathFile stringByAppendingString:@"_bak"] error:nil];
    
    //创建文件句柄 文件指针 用以操作文件的内容
    NSFileHandle *fh = [NSFileHandle fileHandleForUpdatingAtPath:pathFile];
    //读取文件的信息
    NSData *data = [fh readDataToEndOfFile];  //这样会使的当前文件指针fh指向末尾
    NSString *dataString = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
    
    //判断当前字符串对象中是否包含有oldWord
    if ([dataString containsString:oldString]) {
        dataString = [dataString stringByReplacingOccurrencesOfString:oldString withString:newString];
    }
    
    //将文件清空，之后将字符串写回到文件中
    [fh truncateFileAtOffset:0];
    [fh writeData:[dataString dataUsingEncoding:NSUTF8StringEncoding]];
    
    //同步文件。  关闭线程锁
    [fh synchronizeFile];
    [fh closeFile];
}


//替换指定目录下所有指定类型的文件中的字符串
+ (void)replaceInDirectory:(NSString *)pathDirectory withOldString:(NSString *)oldString withNewString:(NSString *)newString InType:(NSString *)typeFile
{
    NSFileManager *fm = [NSFileManager defaultManager];
    //深层次的遍历目录
    NSArray *arrayFile = [fm subpathsOfDirectoryAtPath:pathDirectory error:nil];
    
    for (NSString *item in arrayFile) {
        //获取文件的后缀名
        if ([typeFile isEqualToString:[item pathExtension]]) {
            [self replaceInDirectory:[pathDirectory stringByAppendingFormat:@"/%@",item] withOldString:oldString withNewString:newString];
        }
    }
}