object-c中NSFileManger 和NSFileHandler的用法(2)

 

 

文件定时读取(即用定时器读取NSTime）注意定时器一般在一个类里面设置

//
//  WriteData.m
//  FileMangerTask1
//
//  Created by ganchaobo on 13-5-4.
//  Copyright (c) 2013年 ganchaobo. All rights reserved.
//

#import "WriteData.h"

@interface WriteData()
-(void)startwrite:(NSTimer *) time;
@end

@implementation WriteData

-(void)Runwrite{
    //创建目录
    NSFileManager *fileManager=[NSFileManager defaultManager];
   BOOL isscuess= [fileManager createFileAtPath:@"/Users/ganchaobo/Desktop/1.text" contents:nil attributes:nil];
    if(isscuess){
        NSLog(@"create success");
    }
   NSFileHandle *filehandle=[NSFileHandle fileHandleForUpdatingAtPath:@"/Users/ganchaobo/Desktop/1.text"];
    [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(startwrite:) userInfo:filehandle repeats:YES];
}


-(void)startwrite:(NSTimer *) time{
    NSFileHandle * handle=[time userInfo];
    static int count=0;
    [handle seekToEndOfFile];
    //对内容的描述
    NSDate *date=[NSDate date];
    NSDateFormatter *formatter=[[[NSDateFormatter alloc] init] autorelease];
   formatter.dateFormat=@"yyyy-MM-dd hh:mm:ss";
    NSString *str= [formatter stringFromDate:date];
    str=[str stringByAppendingString:@"\n"];
    
    NSData *date1=[str dataUsingEncoding:NSUTF8StringEncoding] ;
    [handle writeData:date1];
    
    
    if(count==10){
        [time invalidate] ;
        [handle closeFile];
    }
    count++;

}
@end

 拷贝一个大文件 以500字节进行分段读取

void copybigfile(){
    NSString *newpath=@"/Users/ganchaobo/Desktop/1_bar.rar";
    NSString *orginpath=@"/Users/ganchaobo/Desktop/1.rar";
    NSFileManager *filemanger=[NSFileManager defaultManager];
    BOOL issuccess=[filemanger createFileAtPath:newpath contents:nil attributes:nil];
    if(issuccess){
        NSLog(@"create success");
    }
    NSFileHandle *orginhandle=[NSFileHandle fileHandleForReadingAtPath:orginpath];
    NSFileHandle *newhandle=[NSFileHandle fileHandleForWritingAtPath:newpath];
    //要算出文件的大小
    NSError *error=nil;
    NSDictionary *dic= [filemanger attributesOfItemAtPath:orginpath error:&error];
    if(error){
        NSLog(@"read file size filder");
    }
    
    NSNumber *  filesize=[dic objectForKey:NSFileSize];
    NSInteger * longsize=[filesize longValue];//文件的大小
    
    BOOL isEnd=YES;
    NSData *date=nil;
    NSInteger readsize=0;
    while (isEnd) {
        
        if(longsize-readsize<500){
            date=[orginhandle readDataOfLength:readsize];
            isEnd=NO;   
        }
        else{
            
            date=[orginhandle readDataOfLength:500];
        }
        
        readsize=readsize+500;
        [newhandle writeData:date];
    }
    
    [newhandle closeFile];
    [orginhandle closeFile];
    
}