+ (void)downLoadPdf:(NSString *)url pdf_id:(NSString *)pdf_id block:(APIFilePath)pdfFilePath {

    NSMutableDictionary *mPdf_dic = [NSMutableDictionary dictionaryWithDictionary:[Tool getLocalKey:PDFLOCAL_DIC]];

    NSURL *URL = [NSURL URLWithString:url];

    NSURLRequest *request = [NSURLRequest requestWithURL:URL];

   

    NSURLSessionConfiguration *configuration = [NSURLSessionConfiguration defaultSessionConfiguration];

    AFURLSessionManager *manager = [[AFURLSessionManager alloc] initWithSessionConfiguration:configuration];

   

    NSURLSessionDownloadTask *downloadTask = [manager downloadTaskWithRequest:request progress:nil destination:^NSURL *(NSURL *targetPath, NSURLResponse *response) {

       

        NSURL *documentsDirectoryURL = [[NSFileManager defaultManager] URLForDirectory:NSDocumentDirectory inDomain:NSUserDomainMask appropriateForURL:nil create:NO error:nil];

        NSLog(@"###%@", targetPath);  //原始文件

        NSLog(@"**%@", [response suggestedFilename]);  //文件名

        return [documentsDirectoryURL URLByAppendingPathComponent:[response suggestedFilename]];

       

    } completionHandler:^(NSURLResponse *response, NSURL *filePath, NSError *error) {

        NSLog(@"File downloaded to: %@", filePath);//下载成功后本地保存id以及文件路径

        NSString *stringUrl = [filePath absoluteString];

        mPdf_dic[pdf_id] = stringUrl;

        NSDictionary *pdfDic = [NSDictionary dictionaryWithDictionary:mPdf_dic];

        [Tool saveLocalvalue:pdfDic key:PDFLOCAL_DIC];

        pdfFilePath(stringUrl);

    }];

    [downloadTask resume];

}

 

*********************************************************************************************

查看文档时判断本地是否已经下载

#pragma mark - read

- (void)read {

    //本地已下载pdf文件

    NSDictionary *pdfDic = [Tool getLocalKey:PDFLOCAL_DIC];

    if (pdfDic == nil) {

        [Tool saveLocalvalue:pdfDic key:PDFLOCAL_DIC];

    }

    //文件路径

    NSString *filePathLocal;

    NSString *fileUrl = @"pdf的URL";

    NSString *fileKey = @"1471509244417_1471509259460";

    NSArray *keys = [pdfDic allKeys];

    BOOL isDownload = NO; //是否已经下载

    for (NSString *key in keys) {

        if ([key isEqualToString:fileKey]) {

            isDownload = YES;

            break;

        } else {

            isDownload = NO;

        }

    }

    if (isDownload) {

        filePathLocal = pdfDic[fileKey];

        [self openPdf:filePathLocal];

    } else {

         [WYAPI downLoadPdf:fileUrl pdf_id:fileKey block:^(NSString *filePath) {

             [self openPdf:filePath];

         }];

    }

}