iOS 下载图片 －当后台返回的数据是文件流而不是图片url

NSString *urlStr = [NSString stringWithFormat:@"%@uploadFileRest/downFile",[AFAppDotNetAPIClient getUrl]];

NSURL *url = [NSURL URLWithString:urlStr];

NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];

request.HTTPMethod = @"POST";

NSString *post = [NSString stringWithFormat:@"contentType=%@&fileName=%@&filePath=%@",model.CONTENT_TYPE,model.FILE_NAME,model.FILE_PATH];

request.HTTPBody = [post dataUsingEncoding:NSUTF8StringEncoding];

NSURLSession *session = [NSURLSession sharedSession];

// 可以不必创建请求直接用url进行获取，但是只能应用于get请求

NSURLSessionTask *task = [session dataTaskWithRequest:request completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {

if (error) {

UIAlertController *alert = [UIAlertController alertControllerWithTitle:@"提示" message:error.localizedDescription preferredStyle: UIAlertControllerStyleAlert];

UIAlertAction *okAction = [UIAlertAction actionWithTitle:@"确定" style:(UIAlertActionStyleDefault) handler:^(UIAlertAction *action) {

}];

[alert addAction:okAction];

//弹出提示框；

[self presentViewController:alert animated:true completion:nil];

}else

{

image1 = [UIImage imageWithData:data];

dispatch_async(dispatch_get_main_queue(), ^

{

// 更UI

UIImageView *imgView1 = [[UIImageView alloc]initWithFrame:CGRectMake(10, 10, 200, 200)];

// imgView.backgroundColor = [UIColor yellowColor];

imgView1.image = image1;

[self.view addSubview:imgView1];

});

}

}];

[task resume];