【IOS自定义工具类之缓存助手类】CacheHelper

来源：互联网发布：匹配域名的正则表达式编辑：程序博客网时间：2024/04/28 23:47

头文件：

#import <Foundation/Foundation.h>@interface CacheHelper : NSObject {    }+ (void) setObject:(NSData *) data forKey:(NSString *) key withExpires:(int) expires;+ (NSData *) get:(NSString *) key;+ (void) clear;+ (NSString *)getTempPath:(NSString*)key;+ (BOOL)fileExists:(NSString *)filepath;+ (BOOL)isExpired:(NSString *) key;@end

实现文件：

#import "CacheHelper.h"@implementation CacheHelper+ (void) setObject:(NSData *) data forKey:(NSString *) key withExpires:(int) expires{NSDate *dt = [NSDate date];double now = [dt timeIntervalSince1970];    NSMutableString *expiresString = [[NSMutableString alloc] init];NSData *dataExpires = [[expiresString stringByAppendingFormat:@"%f",now+expires] dataUsingEncoding:NSUTF8StringEncoding];[expiresString release];    //创建缓存时间控制文件[dataExpires writeToFile:[[self getTempPath:key] stringByAppendingFormat:@"%@",@".expires"] atomically:NO];    //创建缓存文件，写入缓存    [data writeToFile:[self getTempPath:key] atomically:NO];}+ (NSData *) get:(NSString *) key{if(![self fileExists:[self getTempPath:key]] || [self isExpired:[self getTempPath:key]]){NSLog(@"no cache");    return nil;}    NSData *data = [NSData dataWithContentsOfFile:[self getTempPath:key]];return data;}+ (void) clear{    }//获取临时文件目录+ (NSString *)getTempPath:(NSString*)key{NSString *tempPath = NSTemporaryDirectory();return [tempPath stringByAppendingPathComponent:key];}//判断文件是否存在+ (BOOL)fileExists:(NSString *)filepath{NSFileManager *fileManager = [NSFileManager defaultManager];return [fileManager fileExistsAtPath:filepath];}//判断是否过期+ (BOOL)isExpired:(NSString *) filepath{NSData *data = [NSData dataWithContentsOfFile:[filepath stringByAppendingFormat:@"%@",@".expires"]];NSString *expires = [[NSString alloc] initWithData:data  encoding:NSUTF8StringEncoding];double exp = [expires doubleValue];[expires release];NSDate *dt = [NSDate date];double value = [dt timeIntervalSince1970];if(exp > value){return NO;}return YES;}@end

转自：http://blog.csdn.net/lilizing/article/details/8553186

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