使用 MTOM 进行 WS 下载操作 [英] WS Download operation with MTOM

问题描述

我想通过带有 MTOM 的 WS 直接从 Oracle 数据库 blob 文件流式传输到 WS 客户端.

I want to stream directly from an Oracle database blobs files via WS with MTOM directly to the WS client.

我以为我找到了这里描述的方法:

I thought I found a way which is described here:

http://www.java.net/forum/topic/glassfish/metro-and-jaxb/mtom-best-practices

但是在我查看了 InputStreamDataSource 和 javax.mail.util.ByteArrayDataSource 之后，我意识到它们在内存中实际包含了文档"的一个字节 []，这意味着流媒体的想法是徒劳的，导致我试图避免是在内存中同时拥有多个文档.

but after i took a look on InputStreamDataSource and javax.mail.util.ByteArrayDataSource i realized that they acutal hava a byte[] of the 'document' in memory meaning the streaming ideea is in vain, cause what i try to avoid is to have multiple docs in the same time fully in memory.

那么我如何通过 WS 和 MTOM 从 DB 流式传输到 WS 客户端?

So how can I stream from DB via WS and MTOM to a WS client ?

有什么想法吗?

谢谢

克里斯

推荐答案

我尝试过尝试，最后我得到了一些积极的结果.

I tried experimenting and finally i had some positive results.

为了从数据库直接流式传输到客户端浏览器，上述事情是有效的，但 InputStreamDataSource 应该是这样的:

In order to stream from DB directly to clients browser the above things are valid but the InputStreamDataSource should be like this:

public class InputStreamDataSource implements DataSource {
    private InputStream inputStream;

    public InputStreamDataSource(InputStream inputStream) {
        this.inputStream = inputStream;
    }

    public InputStream getInputStream() throws IOException {
        return inputStream;
    }

    public OutputStream getOutputStream() throws IOException {
        throw new UnsupportedOperationException("Not implemented");
    }

    public String getContentType() {
        return "*/*";
    }

    public String getName() {
        return "InputStreamDataSource";
    }
}

我害怕的是，一旦我自己关闭了输入流......ws 客户端没有收到二进制内容...

What I was affraid is that once I closed the input stream myself... the ws client did not received the binary content...

我检查了一下，实际上DataHandler创建了一个新线程并关闭了输入流

Than i check and actually the DataHandler creates a new thread and closes the input stream

我能够快速地将 500MB 从数据库传输到客户端，并且内存占用低！

I was able to stream 500MB from DB to client fast and with low memory footprint !

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