Returning an excel document via a Java REST service with Apache Wink

Question

I need to return a Microsoft Excel file from a Java REST service. I'm using WebSphere 8.5 which inherently uses Apache Wink as it's JAX-RS implementation; that's a requirement which I can not change. I am also using Java 7 JDK. Here is the error I'm receiving:

org.apache.wink.server.internal.handlers.FlushResultHandler handleResponse The system could not find a javax.ws.rs.ext.MessageBodyWriter or a DataSourceProvider class for the com.somewhere.else.message.core.BaseResponseMessage type and application/vnd.ms-excel mediaType. Ensure that a javax.ws.rs.ext.MessageBodyWriter exists in the JAX-RS application for the type and media type specified.

Here is my Java Resource class method:

@GET
@Path("/report")
@Produces("application/vnd.ms-excel")
public Response getReport() { 

    int fileSize = 0;

    byte[] reportByteArray = null;

    ResponseBuilder responseBuilder = null;
    InputStream report = null;

    BaseResponseMessage<InputStream> baseResponseMessage = new  
    BaseResponseMessage<InputStream>();

    Path reportPath = null;

    String localPath = "C:/Users/me/Report.xls";

    responseBuilder = Response.ok(baseResponseMessage); 

    responseBuilder.header("Content-Description", "File Transfer");
    responseBuilder.header("Content-Disposition", "attachment; 
         filename=Report.xls");
    responseBuilder.header("Content-Transfer-Encoding", "binary");
    responseBuilder.header("Connection", "Keep-Alive");

    reportPath = Paths.get(localPath);

    if (Files.exists(reportPath)) {

        if (Files.isReadable(reportPath)) {

            reportByteArray = Files.readAllBytes(reportPath);

            report = new ByteArrayInputStream(reportByteArray);
        }
    }

    fileSize = report.available();

    responseBuilder.header("Content-Length", fileSize);

    baseResponseMessage.setPayload(report);

    return responseBuilder.build();
}

I do know from looking at the debugger that the path and the excel file are found correctly, and the fileSize is populated correctly as well.

I will gladly provide any more information that is needed. Thank you for your time!

Answer 1

I think the problem is on the @Produces annotation. JAX-RS may not know how to handle "application/vnd.ms-excel" by default. You can try using

@Produces( MediaType.APPLICATION_OCTET_STREAM)

Here is the sample code,

1. Create a JEE 6 web project

2. Created an Application Class

   import javax.ws.rs.ApplicationPath;  
   import javax.ws.rs.core.Application; 
   
   @ApplicationPath("/services/*")  
   public class MyApplication extends Application {  
   
   }  
   

3. Created a REST Resource class,

   import java.io.File;  
   import javax.ws.rs.GET;  
   import javax.ws.rs.Path;  
   import javax.ws.rs.Produces;  
   import javax.ws.rs.core.MediaType;  
   import javax.ws.rs.core.Response;  
   import javax.ws.rs.core.Response.ResponseBuilder;  
   
   
   @Path("/hello")  
   public class HelloResource {  
   
       @GET  
       @Path("excel")  
       @Produces(MediaType.APPLICATION_OCTET_STREAM)  
       public Response test2() {  
           File file = new File("C:/users/arun/rest-test.xlsx");  
           ResponseBuilder rb = Response.ok(file);  
           rb.header("content-disposition", "attachment; filename=rest-test.xlsx");  
           return rb.build();  
       }  
   }