Question

我想建立一个小项目。

我这样做：

1）自动将RGB图像从已知的互联网地址下载到亚马逊AWS。

2）将图像转换为灰度（最终将进行更高级的图像处理）。

3）将灰度图像存储在amazon AWS中。

4）能够在网络浏览器中查看/下载灰度图像。

我知道的编程语言是matlab和基础java（OOP大学课程）。

有没有一步一步的指南？

我应该从哪里开始？

Answer 1

请阅读java.net.HttpURLConnection的文档，了解如何使用Java下载文件。

然后阅读http://docs.aws.amazon.com/AWSJavaSDK/latest/javadoc/index.html，其中介绍了如何下载和上传到Amazon S3。以下是来自Java的S3的示例：

//---------------------------------------------------------------------     
// Amazon S3
//---------------------------------------------------------------------     
class S3 extends AmazonS3Client
 {final String bucket;
  S3(String u, String p, String Bucket)
   {super(new BasicAWSCredentials(u, p));
    bucket = Bucket;
   }
  boolean put(String k, String v)      
   {try 
     {final ByteArrayInputStream b = new ByteArrayInputStream(v.toString().getBytes());
      putObject(bucket, k, b, new ObjectMetadata());
      setObjectAcl(bucket, k, CannedAccessControlList.PublicRead);  // Has to be here to allow change to reduced redundancy
      changeObjectStorageClass(bucket, k, StorageClass.ReducedRedundancy);
      setObjectAcl(bucket, k, CannedAccessControlList.PublicRead);  // Has to be repeated because it is now a new object again
      return true; 
     }
    catch(Exception e) {log("Cannot put "+bucket+"/"+k+" to S3 because "+e);}
    return false; 
   }
  String get(String k) 
   {try 
     {final S3Object f = getObject(bucket, k);
      final BufferedInputStream i = new BufferedInputStream(f.getObjectContent());  
      final StringBuilder s = new StringBuilder(); 
      final byte[]b = new byte[1024];
      for(int n = i.read(b); n != -1; n = i.read(b)) {s.append(new String(b, 0, n));}
      return s.toString(); 
     }
    catch(Exception e) {log("Cannot get "+bucket+"/"+k+" from S3 because "+e);}
    return null; 
   }
  String[]list(String d) 
   {try 
     {final ObjectListing l = listObjects(bucket, d);
      final List<S3ObjectSummary> L = l.getObjectSummaries(); 
      final int n = L.size();
      final String[]s = new String[n];  
      for(int i = 0; i < n; ++i)
       {final S3ObjectSummary k = L.get(i);
        s[i] = k.getKey();
       } 
      return s; 
     }
    catch(Exception e) {log("Cannot list "+bucket+"/"+d+" on S3 because "+e);}
    return new String[]{}; 
   }
 }

}

在Amazon S3上拥有图像后，您可以将文件公开显示，从而可以在任何Web浏览器中显示。

亚马逊AWS - 从网上下载图像并操纵它们

1 个答案: