JAX-RS ChunkedOutput and ChunkedInput Example

In Jersey you can use ChunkedOutput to send response to a client in chunks. By using a chunked output the jersey runtime is informed that the response will be chunked and that the processing works asynchronously in a non-blocking fashion.

ChunkedOutput

In the following example we return a ChunkedOutput instance. This informs Jersey that the response will be asynchronously processed. Usually, a long running method will be executed and as soon the method returns, the response will be sent to the client.

package com.memorynotfound.jaxrs.chunked;

import org.glassfish.jersey.server.ChunkedOutput;
import javax.ws.rs.*;
import java.io.*;

@Path("/numbers")
public class NumbersResource {

    @GET
    public ChunkedOutput<String> streamExample(){
        final ChunkedOutput<String> output = new ChunkedOutput<String>(String.class);

        new Thread() {
            @Override
            public void run() {
                try {
                    for (int i = 0; i < 100000 ; i++){
                        output.write(i + " ");
                    }
                } catch (IOException e){
                    e.printStackTrace();
                } finally {
                    try {
                        output.close();
                    } catch (IOException e){
                        e.printStackTrace();
                    }
                }
            }
        }.start();
        return output;
    }

}

ChunkedInput

On the client side, we use the ChunkedInput to receive chunked messages. The following example shows how to read from ChunkedInput.

package com.memorynotfound.jaxrs.chunked;

import org.glassfish.jersey.client.ChunkedInput;
import javax.ws.rs.client.Client;
import javax.ws.rs.client.ClientBuilder;
import javax.ws.rs.core.GenericType;
import javax.ws.rs.core.Response;

public class RunClient {

    public static void main(String... args){
        Client client = ClientBuilder.newClient();

        Response response = client
                .target("http://localhost:8081/jaxrs-chuncked/api")
                .path("numbers")
                .request()
                .get();

        ChunkedInput<String> input = response.readEntity(new GenericType<ChunkedInput<String>>() {});


        String chunk;
        while ((chunk = input.read()) != null){
            System.out.println("chunk: " + chunk);
        }
    }
}

References

• ChunkedOutput Jersey Doc
• ChunkedOutput JavaDoc
• ChunkedInput JavaDoc

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