【IPHONE开发-OBJECTC入门学习】文件的操作,读写复制文件

#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

#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

#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;
}