【IPHONE开发-OBJECTC入门学习】文件的操作,读写复制文件

转自：http://blog.csdn.net/java886o/article/details/9041547

FileTools.h

#import <Foundation/Foundation.h>
//文件工具类
@interface FileTools : NSObject

//复制文件
+ (void) copyFileWithSrcFile:(NSString*) srcFilePath withBakFile:(NSString*) bakFilePath;

//获取文件的大小
+ (NSNumber*) fileLengthWithFile:(NSString*) filePath;

@end

FileTools.m

#import "FileTools.h"

@implementation FileTools

//复制文件
+ (void) copyFileWithSrcFile:(NSString*) srcFilePath withBakFile:(NSString*) bakFilePath {
    //1.利用NSFileManager复制文件
    //NSFileManager* manager = [NSFileManager defaultManager];
    //[manager copyItemAtPath:srcFilePath toPath:bakFilePath error:nil];
    
    
    //2.利用读原文件,写新文件复制文件
    NSFileManager* fileManager = [NSFileManager defaultManager];
    
    //创建新文件
    BOOL createResult = [fileManager createFileAtPath:bakFilePath contents:nil attributes:nil];
    if (createResult) {
        NSLog(@"文件创建成功...");
    }else {
        NSLog(@"文件创建失败...");
        return;
    }
    
    
    NSFileHandle* inStream = [NSFileHandle fileHandleForReadingAtPath:srcFilePath];
    
    //特别注意-----必须先创建文件再创建outStream,否则将出现拷贝文件大小为0的问题
    
    NSFileHandle* outStream = [NSFileHandle fileHandleForWritingAtPath:bakFilePath];
    
 
    
    //初始化变量
    NSInteger readCount = 0;
    NSInteger fileSize = [[self fileLengthWithFile:srcFilePath] intValue];

    NSLog(@"复制的文件大小为:%ld",fileSize);

    BOOL isCanRead = YES;
    NSData* bufferData = nil;
    
    while(isCanRead) { //如果可以读文件,则开始读文件
        [inStream seekToFileOffset:readCount];
        if ((fileSize - readCount) < (1024 * 8)) { //如果剩下可读的文件小于8K,则直接读取到文件末尾,并保存文件,然后结束读取文件
            bufferData = [inStream readDataToEndOfFile];
            isCanRead = false;
            [outStream writeData:bufferData];
            break;
        }else { //如果剩余的刻度文件大于等于8K,则跳转到已读文件位置,并读取8K的数据,保存文件,然后继续读取
            bufferData = [inStream readDataOfLength:(1024 * 8)];
            readCount+= (1024 * 8);
            [outStream writeData:bufferData];

        }
    }
    
    [outStream closeFile];
    [inStream closeFile];
       
    NSLog(@"文件拷贝完成...");
}

//获取文件大小
+ (NSNumber*) fileLengthWithFile:(NSString*) filePath {
    NSFileManager* manager = [NSFileManager defaultManager];
    NSDictionary* attrs = [manager attributesOfItemAtPath:filePath error:nil];
    return [attrs objectForKey:NSFileSize];
}


@end

 

测试 main.m

 

 

#import <Foundation/Foundation.h>
#import "FileTools.h"

int main(int argc, const char * argv[])
{

    @autoreleasepool {

        NSNumber* size = [FileTools fileLengthWithFile:@"/Users/3g2win/Downloads/ios_development.cer"];
        NSLog(@"文件大小:%d",[size intValue]);
        [FileTools copyFileWithSrcFile:@"/Users/3g2win/Downloads/ios_development.cer" withBakFile:@"/Users/3g2win/Downloads/ios_development_备份.cer"];

    }
    return 0;
}