zoukankan      html  css  js  c++  java

  • 【转】iphone 输入/输出流异步读写数据

     

    原文：iphone 输入/输出流异步读写数据

    分类： iphone2012-05-30 14:50 2484人阅读 评论(1) 收藏 举报
    iphoneattributesinterfacepathstreamfile

    1、首先是往文件里写入数据

    WriteFile.h

    [cpp] view plaincopy
    1. #import <Foundation/Foundation.h>  
    2. #import <UIKit/UIKit.h>  
    3. @class NoteDb;  
    4. @interface WriteFile : NSObject<NSStreamDelegate>{  
    5.     //文件地址  
    6.     NSString *parentDirectoryPath;  
    7.     //输出流，写数据  
    8.     NSOutputStream *asyncOutputStream;  
    9.     //写数据的内容  
    10.     NSData *outputData;  
    11.     //位置及长度  
    12.     NSRange outputRange;  
    13.     //数据的来源  
    14.     NoteDb *aNoteDb;  
    15. }  
    16. @property (nonatomic,retain) NSData *outputData;  
    17. @property (nonatomic,retain) NoteDb *aNoteDb;  
    18. //写数据  
    19. -(void)write;  
    20. @end  

    实现文件WriteFile.m
    [cpp] view plaincopy
    1. #import "WriteFile.h"  
    2. #import "NoteDb.h"  
    3. @implementation WriteFile  
    4. @synthesize outputData,aNoteDb;  
    5.   
    6. -(id)init{  
    7.     self=[super init];  
    8.     if (!self) {  
    9.         [self release];  
    10.         return nil;  
    11.     }  
    12.     outputData=[[NSData alloc]init];  
    13.     aNoteDb=[[NoteDb alloc]init];  
    14.     return self;  
    15. }  
    16. -(void)write{  
    17.     //NSLog(@"%@",self.aNoteDb);  
    18.     //沙盒路径  
    19.     NSArray *paths= NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);  
    20.     NSString *documentsDirectory = [paths objectAtIndex:0];  
    21.     //文件名字是note.txt  
    22.     NSString *path = [documentsDirectory stringByAppendingPathComponent:@"note.txt"];  
    23.       
    24.     [asyncOutputStream release];  
    25.     parentDirectoryPath = path;  
    26.     //数据源  
    27.     NSData *tmpdata = [NSKeyedArchiver archivedDataWithRootObject:self.aNoteDb.noteList];  
    28.       
    29.     //self.outputData=[[NSData alloc]initWithData:tmpdata];  
    30.     self.outputData=tmpdata;  
    31.     //位置从哪开始  
    32.     outputRange.location=0;  
    33.     //创建文件  
    34.     [[NSFileManager defaultManager] createFileAtPath:parentDirectoryPath  
    35.                                             contents:nil attributes:nil];  
    36.     //初始化输出流  
    37.     asyncOutputStream = [[NSOutputStream alloc] initToFileAtPath: parentDirectoryPath append: NO];  
    38.     //回调方法，  
    39.     [asyncOutputStream setDelegate: self];   
    40.     //异步处理，  
    41.     [asyncOutputStream scheduleInRunLoop:[NSRunLoop currentRunLoop]  forMode:NSDefaultRunLoopMode];  
    42.     //打开异步输出流  
    43.     [asyncOutputStream open];   
    44.       
    45.       
    46. }  
    47. -(void)stream:(NSStream *)theStream handleEvent:(NSStreamEvent)streamEvent{  
    48.    // NSLog(@"as");  
    49.     NSOutputStream *outputStream = (NSOutputStream*) theStream;  
    50.     BOOL shouldClose = NO;  
    51.     switch (streamEvent)   
    52.     {  
    53.         case NSStreamEventHasSpaceAvailable://读事件   
    54.         {  
    55.             //缓冲区  
    56.             uint8_t outputBuf [1];  
    57.             //长度  
    58.             outputRange.length = 1;  
    59.             //把数据放到缓冲区中  
    60.             [outputData getBytes:&outputBuf range:outputRange];   
    61.             //把缓冲区中的东西放到输出流  
    62.             [outputStream write: outputBuf maxLength: 1];   
    63.             //判断data数据是否读完  
    64.             if (++outputRange.location == [outputData length])   
    65.             {    
    66.                 shouldClose = YES;  
    67.             }  
    68.             break;  
    69.         }  
    70.         case NSStreamEventErrorOccurred:  
    71.         {  
    72.             //出错的时候  
    73.             NSError *error = [theStream streamError];  
    74.             if (error != NULL)   
    75.             {  
    76.                 UIAlertView *errorAlert = [[UIAlertView alloc]  
    77.                                            initWithTitle: [error localizedDescription]  
    78.                                            message: [error localizedFailureReason]  
    79.                                            delegate:nil  
    80.                                            cancelButtonTitle:@"OK"  
    81.                                            otherButtonTitles:nil];  
    82.                 [errorAlert show];  
    83.                 [errorAlert release];  
    84.             }  
    85.             shouldClose = YES;  
    86.             break;  
    87.         }  
    88.         case NSStreamEventEndEncountered:  
    89.             shouldClose = YES;  
    90.     }  
    91.     if (shouldClose)  
    92.     {  
    93.         //当出错或者写完数据，把线程移除  
    94.         [outputStream removeFromRunLoop: [NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];  
    95.         //最后关掉输出流  
    96.         [theStream close];   
    97.     }  
    98.   
    99. }  
    100. -(void)dealloc{  
    101.     [outputData release];  
    102.     [aNoteDb release];  
    103.     [super dealloc];  
    104. }  
    105. @end  

    2、其次是从文件里读出数据

    ReadFile.h

    [cpp] view plaincopy
    1. #import <Foundation/Foundation.h>  
    2. @class NoteDb;  
    3. @interface ReadFile : NSObject<NSStreamDelegate>{  
    4.     //路径  
    5.     NSString *parentDirectoryPath;  
    6.     //异步输出流  
    7.     NSInputStream *asyncInputStream;  
    8.     //读出来的数据  
    9.     NSMutableData *resultData;  
    10.     //返回去的数据  
    11.     NoteDb *aNoteDb;  
    12. }  
    13. @property(nonatomic,retain)NoteDb *aNoteDb;  
    14. @property (nonatomic, retain) NSMutableData *resultData;  
    15. //开始读数据  
    16. -(void)read;  
    17. //读出来的数据追加到resultData上  
    18. - (void)appendData:(NSData*)_data;  
    19. //  
    20. - (void)dataAtNoteDB;  
    21. //返回去的数据  
    22. - (NoteDb*)getNoteDb;  
    23. @end  

    实现文件ReadFile.m
    [cpp] view plaincopy
    1. #import "ReadFile.h"  
    2. #import "NoteDb.h"  
    3. #import "NoteList.h"  
    4. #import "WriteFile.h"  
    5. @implementation ReadFile  
    6. @synthesize aNoteDb,resultData;  
    7. -(id)init{  
    8.     self=[super init];  
    9.     //aNoteDb=[[NoteDb alloc]init];  
    10.     resultData=[[NSMutableData alloc]init];  
    11.     return self;  
    12. }  
    13. -(void)read{  
    14.     //沙盒路径  
    15.     NSArray *paths= NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);  
    16.     NSString *documentsDirectory = [paths objectAtIndex:0];  
    17.     //文件名  
    18.     NSString *path = [documentsDirectory stringByAppendingPathComponent:@"note.txt"];  
    19.     /* 
    20.     if(![[NSFileManager defaultManager]fileExistsAtPath:path]){ 
    21.         //如果不存在，就新建 
    22.         WriteFile *file=[[WriteFile alloc]init]; 
    23.         [file write]; 
    24.         [file release];         
    25.     }else{ 
    26.         NSLog(@"有note.txt文件"); 
    27.     } 
    28.     */  
    29.     [asyncInputStream release];  
    30.     parentDirectoryPath = path;  
    31.     //异步输入流初始化，并把赋于地址  
    32.     asyncInputStream =  
    33.     [[NSInputStream alloc] initWithFileAtPath: parentDirectoryPath];  
    34.     //设置代理（回调方法、委托）  
    35.     [asyncInputStream setDelegate: self];  
    36.     //设置线程，添加线程，创建线程：Runloop顾名思义就是一个不停的循环，不断的去check输入  
    37.     [asyncInputStream scheduleInRunLoop:[NSRunLoop currentRunLoop]  
    38.                                 forMode:NSDefaultRunLoopMode];  
    39.     //打开线程  
    40.     [asyncInputStream open];  
    41.   
    42. }  
    43. //追加数据  
    44. - (void)appendData:(NSData*)_data{  
    45.     [resultData appendData:_data];  
    46. }  
    47. //回调方法，不停的执行  
    48. -(void)stream:(NSStream *)theStream handleEvent:(NSStreamEvent)streamEvent{  
    49.     BOOL shouldClose = NO;  
    50.     NSInputStream *inputStream = (NSInputStream*) theStream;  
    51.      //NSLog(@"as");  
    52.     switch (streamEvent)   
    53.     {  
    54.         case NSStreamEventHasBytesAvailable:   
    55.         {         
    56.             //读数据  
    57.             //读取的字节长度  
    58.             NSInteger maxLength = 128;   
    59.             //缓冲区  
    60.             uint8_t readBuffer [maxLength];   
    61.             //从输出流中读取数据，读到缓冲区中  
    62.             NSInteger bytesRead = [inputStream read: readBuffer   
    63.                                           maxLength:maxLength];  
    64.             //如果长度大于0就追加数据  
    65.             if (bytesRead > 0)   
    66.             {  
    67.                 //把缓冲区中的数据读成data数据   
    68.                 NSData *bufferData = [[NSData alloc]  
    69.                                       initWithBytesNoCopy:readBuffer   
    70.                                       length:bytesRead   
    71.                                       freeWhenDone:NO];  
    72.                 //追加数据  
    73.                 [self appendData:bufferData];  
    74.                 //release掉data  
    75.                 [bufferData release];  
    76.             }  
    77.             break;  
    78.         }   
    79.         case NSStreamEventErrorOccurred:   
    80.         {  
    81.             //读的时候出错了  
    82.             NSError *error = [theStream streamError];  
    83.             if (error != NULL)   
    84.             {  
    85.                 UIAlertView *errorAlert = [[UIAlertView alloc]  
    86.                                            initWithTitle: [error localizedDescription]  
    87.                                            message: [error localizedFailureReason]  
    88.                                            delegate:nil  
    89.                                            cancelButtonTitle:@"OK"  
    90.                                            otherButtonTitles:nil];  
    91.                 [errorAlert show];  
    92.                 [errorAlert release];  
    93.             }  
    94.             shouldClose = YES;  
    95.             break;  
    96.         }  
    97.         case NSStreamEventEndEncountered:   
    98.         {  
    99.             shouldClose = YES;  
    100.             //数据读完就返回数据  
    101.             [self dataAtNoteDB];              
    102.             [theStream close];  
    103.         }break;  
    104.     }  
    105.     if (shouldClose)  
    106.     {  
    107.         //当文件读完或者是读到出错时，把线程移除  
    108.         [inputStream removeFromRunLoop: [NSRunLoop currentRunLoop]   
    109.                                forMode:NSDefaultRunLoopMode];  
    110.         //并关闭流  
    111.         [theStream close];   
    112.     }  
    113. }  
    114. -(void) dataAtNoteDB{  
    115.     aNoteDb=nil;  
    116.     aNoteDb=[[NoteDb alloc]init];  
    117.     aNoteDb.noteList = [NSKeyedUnarchiver unarchiveObjectWithData:resultData];  
    118.     //NSLog(@"%@",aNoteDb);  
    119.     /* 
    120.     for (id tmp in  aNoteDb.noteList.noteArray)  
    121.     { 
    122.         NSLog(@"tmp = %@",tmp); 
    123.     } 
    124.      */  
    125. }  
    126. - (NoteDb*)getNoteDb{  
    127.     return self.aNoteDb;  
    128. }  
    129. -(void)dealloc{  
    130.     [aNoteDb release];  
    131.     [resultData release];  
    132.     [super dealloc];  
    133. }  
    134. @end  
  • 相关阅读:
    oracle 数据库、实例、服务名、SID
    查看oracle数据库服务器的名字
    oracle表复制
    Oracle 备份、恢复单表或多表数据步骤
    如何查询一个表中有哪些列全为空
    mysql当查询某字段结果为空并赋值
    NoSQL初探之人人都爱Redis：（1）Redis简介与简单安装
    《大型网站技术架构》读书笔记四：瞬时响应之网站的高性能架构
    《大型网站技术架构》读书笔记三：大型网站核心架构要素
    《大型网站技术架构》读书笔记二：大型网站架构模式
  • 原文地址：https://www.cnblogs.com/wangrui-techbolg/p/3965105.html
Copyright © 2011-2022 走看看