/存储publickey和sessionID -- writeContent： nil － 仅取出数据， 其他 － 修改原内容并提取 +(NSString *)storeFile:(NSString *)fileName content:(NSString *)writeContent {     NSString *pathDocuments=[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];     NSString *createPath=[NSString stringWithFormat:@"%@/%@",pathDocuments,fileName];//用文件名补全路径     NSError *ReadFileError;     NSString *readContent ;     NSData *data ;     if ([[NSFileManager defaultManager] fileExistsAtPath:createPath])//判断文件是否已存在     {         if (nil == writeContent) {             readContent = [NSString stringWithContentsOfFile:createPath encoding:NSUTF8StringEncoding error:&ReadFileError;];         }else{             data = [writeContent dataUsingEncoding:NSUTF8StringEncoding];//新文件的初始数据             [[NSFileManager defaultManager] createFileAtPath:createPath contents:data attributes:nil];//创建文件             readContent = [NSString stringWithContentsOfFile:createPath encoding:NSUTF8StringEncoding error:&ReadFileError;];                    }     }     else     {         if (nil == writeContent) {             return nil;         }else{             data = [writeContent dataUsingEncoding:NSUTF8StringEncoding];//新文件的初始数据             [[NSFileManager defaultManager] createFileAtPath:createPath contents:data attributes:nil];//创建文件             readContent = [NSString stringWithContentsOfFile:createPath encoding:NSUTF8StringEncoding error:&ReadFileError;];         }     }     return readContent; } + ( NSArray * )storeArryFile:(NSString *)fileName content:( NSArray *)writeArry {     //步骤     //存 ：将 数组放入 字典     //取： 从字典取出数组     if ( writeArry == nil)//读取文件     {         NSString *storeStr = [FNProRequest storeFile:fileName content:nil];         NSDictionary *dic = (NSDictionary *)[storeStr JSONValue];         NSLog(@"%@", dic);         return (NSArray *)[dic objectForKey:fileName];     }     else     {         NSArray *objectsArry = [[NSArray alloc]initWithObjects:writeArry,nil ];         NSArray *keysArry    = [[NSArray alloc]initWithObjects:fileName,nil ];         NSDictionary *dic = [[NSDictionary alloc]initWithObjects:objectsArry forKeys:keysArry];         NSString *storeStr = [dic JSONRepresentation];         [self storeFile:fileName content:storeStr];         [objectsArry release];         [keysArry release];         [dic release];     }     return nil; }