使用Java Jersey返回一个文件

Question

I am using the Java Jersey to implement a REST service. One thing my service should provide is a file download option. These files are quite big and are constructed from data from db.

Currently I am fetching all data from the db and saving it to a file and returning a

Response.ok().entity(new FileInputStream(file)).build();

Is there a way how I can start serving the file without fully downloading the data from db, but as the data comes from db append it to the Output stream ?

Answer 1

使用JERSEY使用输入和输出二进制流的答案解决了这个问题？

Answer 2

How about

File fileToSend = getFile();
return Response.ok(fileToSend, "application/zip").build();

The media type can be set to match the file being sent.

This looks pretty straight forward but more importantly, do java experts reading this see a performance problem with the solution?

Answer 3

So you want to get a stream from your database ?

I'm not sure it's even possible.

But you don't have to write a temp file to send your data. Instead of writing into the file, you could use a ByteArrayInputStream and put your data there with a byte array.

Answer 4

depends on the type of underlying database connection/driver, if you have access to the JDBC layer (eg using Hibernate) it should be possible to stream data using the JDBC Streaming API, then take the Streams from the ResultSet and pass them into Jersey's Response Builder. I have not done this myself though..

check here:

• JDBC's getBinaryStream()

• An example