学步园

有需求，需要把log文件打印到文件中进行转存，或者上传到服务器， 代码如下：

（要打印的内容为NSString）

方法1. 成功打印，但要注意下面这种方式会不断地打开这个文件，然后不断地关闭文件，（在正常的代码中，应该是打开一次，关闭一次即可，因为打开和关闭文件流的操作是很费时的。）

#define recordFilePath (@"/Users/heqin/Desktop/recordRequstTimeLast.log")

NSDate *curDate = [NSDate
date];

NSTimeInterval lastTimeLength = [curDate
timeIntervalSinceDate:requestHappenDate];

NSString *resultString = [NSString
stringWithFormat:@"%@, interval=%f, success=%@", [request.url
path], lastTimeLength, success?@"YES":@"NO"];

FILE *file = fopen([recordFilePath
UTF8String], [@"ab+"UTF8String]);

if (file !=
NULL) {

   
fseek(file, 0, SEEK_END);

}

NSData *resultData = [resultString dataUsingEncoding:NSUTF8StringEncoding];

int readSize = [resultData
length];

fwrite((const
void *)[resultData
bytes], readSize, 1, file);

fclose(file);

方法2.（这种方法看起来似乎更接近OC代码）

 NSFileManager *file_manager = [NSFileManager defaultManager];
    NSString
*fileName = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,
NSUserDomainMask, YES) objectAtIndex:0]
     stringByAppendingPathComponent:@"xxx.txt"];
    BOOL
isExit = [file_manager fileExistsAtPath:fileName];
    if
(!isExit) {
        [file_manager
createFileAtPath:fileName contents:nil attributes:nil];
    }
    NSFileHandle
*outFile = [NSFileHandle fileHandleForWritingAtPath:fileName];
    //找到并定位到outFile的末尾位置(在此后追加文件)
    [outFile
seekToEndOfFile];
    NSString
*bs = [NSString stringWithFormat:@"@"%@",\n", album.Img];
//    [[bs
dataUsingEncoding:NSUTF8StringEncoding] writeToFile:fileName atomically:YES];
    [outFile
writeData:[bs dataUsingEncoding:NSUTF8StringEncoding]];
    //关闭读写文件
    [outFile
closeFile];

方法3. 

- (NSString*)logFilePath {
 2 //非越狱版路径
 3  #ifndef CRACK
 4      NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
 5      NSString *documentsDirectory = [paths objectAtIndex:0];
 6 //越狱版路径
 7  #else
 8      NSString *documentsDirectory = @"/var/root/Media/xiaodao/";
 9  #endif
10      NSString *logDir = [documentsDirectory stringByAppendingPathComponent:@"logs"];    
11      BOOL isDir = YES;
12      //如果logs文件夹存不存在，则创建
13      if([[NSFileManager defaultManager] fileExistsAtPath:logDir isDirectory:&isDir] == NO)
14      {
15          [[NSFileManager defaultManager] createDirectoryAtPath:logDir withIntermediateDirectories:YES attributes:nil error:nil];
16      }
17      //以当天的时间为文件名，文件名后缀为.log
18      NSString *fileName =[NSString stringWithFormat:@"%@.log",[NSDate date]];
19      NSString *logPath = [logDir stringByAppendingPathComponent:fileName];
20      return logPath;
21  }

// 开始打印

- (void)startLog {
2    freopen([[self logFilePath] cStringUsingEncoding:NSASCIIStringEncoding],"a+",stderr);
3 }
freopen重定向打印
stderr为标准出错信息
// 关闭日志
- (void)finishLog { 
2     fflush(stderr);
3     dup2(dup(STDERR_FILENO), STDERR_FILENO);
4     close(dup(STDERR_FILENO));
5 }
//  删除日志
- (BOOL)deleteLogFile {
2     BOOL success = [[NSFileManager defaultManager] removeItemAtPath:[self logFilePath] error:nil];
3     return success;
4 }