1.NSInputStream文件的讀取流,是將本地的文件讀取到內(nèi)存中去

@property(nonatomic)NSInputStream*inputStream;

// ①文件讀取流的開啟 ?path為需要被讀取的文件路徑 ?

self.inputStream= [[NSInputStreamalloc]initWithFileAtPath:path];

[self.inputStreamsetDelegate:self];

[self.inputStreamscheduleInRunLoop:[NSRunLoopcurrentRunLoop]forMode:NSDefaultRunLoopMode];

[self.inputStreamopen];

// ②在開啟了文件流以后就會在代理方法中執(zhí)行讀取操作

#define HBUFC_BUFFER_SIZE1024 ?//一次最大讀取的字節(jié)

uint8_thbufc_file_buffer[HBUFC_BUFFER_SIZE]; // 一個緩存的數(shù)組

-(void)stream:(NSStream*)stream handleEvent:(NSStreamEvent)eventCode{

switch(eventCode) {

// 有有效讀取字節(jié)的時候進(jìn)入這個case,一次性將所有的流進(jìn)入

caseNSStreamEventHasBytesAvailable:{

// 將HBUFC_BUFFER_SIZE 大小的字節(jié)流放入到緩存數(shù)組hbufc_file_buffer中

longbytes = [(NSInputStream*)streamread:hbufc_file_buffermaxLength:HBUFC_BUFFER_SIZE];

// 進(jìn)行循環(huán)的讀取，注意每次data取的是讀取到的字節(jié)數(shù) 而不是最大字節(jié)數(shù)即bytes

while(bytes >0) {

NSData*data = [NSDatadataWithBytes:hbufc_file_bufferlength:bytes];

[self.dataappendData:data];

bytes = [(NSInputStream*)streamread:hbufc_file_buffermaxLength:HBUFC_BUFFER_SIZE];

}

}

break;

// 流讀取完畢后，進(jìn)入這個case 將流關(guān)閉，并且從runloop中移除

caseNSStreamEventEndEncountered:{

NSString*dataStr = [[NSStringalloc]initWithData:self.dataencoding:(NSUTF8StringEncoding)];

NSLog(@"%@===",dataStr);

[streamclose];

[streamremoveFromRunLoop:[NSRunLoopcurrentRunLoop]forMode:NSDefaultRunLoopMode];

stream =nil;

}

break;

default:

break;

}