1     // 确定URL 2     NSString *urlStr = @"http://localhost/试试看"; 3     urlStr = [urlStr stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]; 4     NSURL *url = [NSURL URLWithString:urlStr]; 5      6     // 确定request 7     NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url cachePolicy:0 timeoutInterval:2.0f]; 8      9     // 确定会话10     NSURLSession *session = [NSURLSession sharedSession];11     12     // 由会话生成任务13     NSURLSessionDataTask *dataTask = [session dataTaskWithRequest:request completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {14         NSLog(@"response-- %@",response);15         NSLog(@"data--%@",data);16         17         // 刷新UI,一定要返回主线程去刷新18         dispatch_async(dispatch_get_main_queue(), ^{19             [self.imageView  setImage:[UIImage imageWithData:data]];20         });21 22     }];23     24     [dataTask resume];

 1     // 确定URL 2     NSString *urlStr = @"http://localhost/试试看"; 3     urlStr = [urlStr stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]; 4     NSURL *url = [NSURL URLWithString:urlStr]; 5      6     // 确定request 7     NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url cachePolicy:0 timeoutInterval:2.0f]; 8      9     // 确定会话10     NSURLSession *session = [NSURLSession sharedSession];11     12     // 由会话生成任务13     NSURLSessionDownloadTask *downloadTask = [session downloadTaskWithRequest:request completionHandler:^(NSURL *location, NSURLResponse *response, NSError *error) {14         // 从tmp中拷贝文件到cache15         NSString *cachePath = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) lastObject];16         NSURL *cachePathURL = [NSURL fileURLWithPath:cachePath];17         NSString *fileNameByMD5 = [[[response URL] absoluteString] MD5];18         NSURL *fileURL = [cachePathURL URLByAppendingPathComponent: fileNameByMD5];19 20         NSFileManager *mgr = [NSFileManager defaultManager];21         [mgr moveItemAtURL:location toURL:fileURL  error:NULL];22         23     }];24     25     [downloadTask resume];

 1 - (NSString *)MD5 2 { 3     const char *cStr = [self UTF8String]; 4     unsigned char digest[CC_MD5_DIGEST_LENGTH]; 5  6     CC_MD5(cStr, strlen(cStr), digest); 7  8     NSMutableString *result = [NSMutableString stringWithCapacity:CC_MD5_DIGEST_LENGTH * 2]; 9 10     for(int i = 0; i < CC_MD5_DIGEST_LENGTH; i++) {11         [result appendFormat:@"%02x", digest[i]];12     }13 14     return result;15 }