In this tutorial we are going to see how to use JAX-WS along with Message Transmission Optimization Mechanism (MTOM) in order to transfer images from a Web Service endpoint to a Client and vise versa. So, in this example we are going to create a Web Service that a client can use in order to download or upload an image. As we know, Web Services uses SOAP messages to communicate with clients that want to use the service. SOAP is an XML based protocol, so it uses XML-Binary Optimized Packaging (XOP) in order to transmit binary data (like an image) over XMl.
It would be very useful to read JAX-WS Hello World Example – RPC Style before proceeding to this example.
1. JAX-WS Web Service End Point
In order to create a Web Service Endpoint:
- First you have to create a Web Service Endpoint Interface. This interface will contain the declerations of all the methods you want to include in the Web Service.
- Then you have to create a class that actually implements the above interface, which will be your Endpoint implementation.
- Finally you create your Endpoint publisher which actually deploys the web service and creates and publishes the endpoint for the specified implementor object at a given address. The necessary server infrastructure will be created and configured by the JAX-WS implementation. You have to run the publisher to make your Web Service available to clients.
Web Service Endpoint Interface (SEI)
ImageServerInterface.java:
package com.javacodegeeks.enterprise.ws.jaxws;
import java.awt.Image;
import javax.jws.WebMethod;
import javax.jws.WebService;
import javax.jws.soap.SOAPBinding;
import javax.jws.soap.SOAPBinding.Style;
@WebService
@SOAPBinding(style = Style.RPC)
public interface ImageServerInterface {
@WebMethod
Image downloadImage(String imageName);
@WebMethod
String uploadImage(Image imageToUpload);
}Web Service Endpoint Implementation
ImageServerImpl.java:
package com.javacodegeeks.enterprise.ws.jaxws;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.jws.WebService;
import javax.xml.ws.WebServiceException;
import javax.xml.ws.soap.MTOM;
@MTOM
@WebService(endpointInterface = "com.javacodegeeks.enterprise.ws.jaxws.ImageServerInterface")
public class ImageServerImpl implements ImageServerInterface{
@Override
public Image downloadImage(String imageName) {
try {
File imageFile = new File("F:\\nikos7\\Desktop\\"+imageName);
Image im = ImageIO.read(imageFile);
return im;
} catch (IOException e) {
e.printStackTrace();
return null;
}
}
@Override
public String uploadImage(Image imageToUpload) {
if(imageToUpload!=null){
File imageFile = new File("C:\\nikos7\\Pictures\\image.jpg");
try {
ImageIO.write(toBufferedImage(imageToUpload), "jpg", imageFile);
} catch (IOException e) {
e.printStackTrace();
return "Upload Failed";
}
return "Upload Complete";
}
throw new WebServiceException("Upload Failed");
}
/**
* Utility to convert Image to BufferedImage in order to save it to a file
* From : https://code.google.com/p/game-engine-for-java/source/browse/src/com/gej/util/ImageTool.java#31
*/
public static BufferedImage toBufferedImage(Image img)
{
if (img instanceof BufferedImage)
{
return (BufferedImage) img;
}
// Create a buffered image with transparency
BufferedImage bimage = new BufferedImage(img.getWidth(null), img.getHeight(null), BufferedImage.TYPE_INT_ARGB);
// Draw the image on to the buffered image
Graphics2D bGr = bimage.createGraphics();
bGr.drawImage(img, 0, 0, null);
bGr.dispose();
// Return the buffered image
return bimage;
}
}There is small problem in the implmentation above. If the service returs a null value you will get the following error
Exception in thread "main" javax.xml.ws.soap.SOAPFaultException: Method Parameter: return cannot be null. This is BP 1.1 R2211 violation.So you have to make sure that your program never returns null. For instance, you can have a default image and return that every time something goes wrong with your program and you get an exception (a checked exception). Or you can have something like a custom Object that will include an image and also a status code, and return that Object every time.
Web Service Endpoint Publisher
ImageServerPublisher.java:
package com.javacodegeeks.enterprise.ws.jaxws;
import javax.xml.ws.Endpoint;
import com.javacodegeeks.enterprise.ws.jaxws.ImageServerImpl;
public class ImageServerPublisher{
public static void main(String[] args) {
Endpoint.publish("http://localhost:9999/webservice/imageService", new ImageServerImpl());
}
}Now when you run the publisher the Web Service will be available to the clients, deployed in the URL:
http://localhost:9999/webservice/imageService
And this is the wsdl file that is automatically created (published in http://localhost:9999/webservice/imageService?wsdl):
WSDL:
<!-- Published by JAX-WS RI at http://jax-ws.dev.java.net. RI's version is JAX-WS RI 2.2.4-b01. --> <!-- Generated by JAX-WS RI at http://jax-ws.dev.java.net. RI's version is JAX-WS RI 2.2.4-b01. --> <definitions xmlns:wsu="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd" xmlns:wsp="http://www.w3.org/ns/ws-policy" xmlns:wsp1_2="http://schemas.xmlsoap.org/ws/2004/09/policy" xmlns:wsam="http://www.w3.org/2007/05/addressing/metadata" xmlns:soap="http://schemas.xmlsoap.org/wsdl/soap/" xmlns:tns="http://jaxws.ws.enterprise.javacodegeeks.com/" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns="http://schemas.xmlsoap.org/wsdl/" targetNamespace="http://jaxws.ws.enterprise.javacodegeeks.com/" name="ImageServerImplService"> <wsp:Policy wsu:Id="ImageServerImplPortBinding_MTOM_Policy"> <ns1:OptimizedMimeSerialization xmlns:ns1="http://schemas.xmlsoap.org/ws/2004/09/policy/optimizedmimeserialization" wsp:Optional="true" /> </wsp:Policy> <types /> <message name="downloadImage"> <part name="arg0" type="xsd:string" /> </message> <message name="downloadImageResponse"> <part name="return" type="xsd:base64Binary" /> </message> <message name="uploadImage"> <part name="arg0" type="xsd:base64Binary" /> </message> <message name="uploadImageResponse"> <part name="return" type="xsd:string" /> </message> <portType name="ImageServerInterface"> <operation name="downloadImage"> <input wsam:Action="http://jaxws.ws.enterprise.javacodegeeks.com/ImageServerInterface/downloadImageRequest" message="tns:downloadImage" /> <output wsam:Action="http://jaxws.ws.enterprise.javacodegeeks.com/ImageServerInterface/downloadImageResponse" message="tns:downloadImageResponse" /> </operation> <operation name="uploadImage"> <input wsam:Action="http://jaxws.ws.enterprise.javacodegeeks.com/ImageServerInterface/uploadImageRequest" message="tns:uploadImage" /> <output wsam:Action="http://jaxws.ws.enterprise.javacodegeeks.com/ImageServerInterface/uploadImageResponse" message="tns:uploadImageResponse" /> </operation> </portType> <binding name="ImageServerImplPortBinding" type="tns:ImageServerInterface"> <wsp:PolicyReference URI="#ImageServerImplPortBinding_MTOM_Policy" /> <soap:binding transport="http://schemas.xmlsoap.org/soap/http" style="rpc" /> <operation name="downloadImage"> <soap:operation soapAction="" /> <input> <soap:body use="literal" namespace="http://jaxws.ws.enterprise.javacodegeeks.com/" /> </input> <output> <soap:body use="literal" namespace="http://jaxws.ws.enterprise.javacodegeeks.com/" /> </output> </operation> <operation name="uploadImage"> <soap:operation soapAction="" /> <input> <soap:body use="literal" namespace="http://jaxws.ws.enterprise.javacodegeeks.com/" /> </input> <output> <soap:body use="literal" namespace="http://jaxws.ws.enterprise.javacodegeeks.com/" /> </output> </operation> </binding> <service name="ImageServerImplService"> <port name="ImageServerImplPort" binding="tns:ImageServerImplPortBinding"> <soap:address location="http://localhost:9999/webservice/imageService" /> </port> </service> </definitions>
2. Web Service Client
This is client that consumes the above Web Service, written in Java:
WebServiceClient.java:
package com.javacodegeeks.enterprise.ws.client;
import java.awt.Image;
import java.io.File;
import java.net.URL;
import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.xml.namespace.QName;
import javax.xml.ws.BindingProvider;
import javax.xml.ws.Service;
import javax.xml.ws.soap.SOAPBinding;
import com.javacodegeeks.enterprise.ws.jaxws.ImageServerInterface;
public class WebServiceClient{
public static void main(String[] args) throws Exception {
URL url = new URL("http://localhost:9999/webservice/imageService?wsdl");
QName qname = new QName("http://jaxws.ws.enterprise.javacodegeeks.com/", "ImageServerImplService");
Service service = Service.create(url, qname);
ImageServerInterface imageServer = service.getPort(ImageServerInterface.class);
/********* Download ***********/
Image image = imageServer.downloadImage("sc.jpg");
//display the received image in a frame
JFrame frame = new JFrame();
frame.setSize(800, 800);
JLabel label = new JLabel(new ImageIcon(image));
frame.add(label);
frame.setVisible(true);
/********* Upload *************/
Image imageToUpload = ImageIO.read(new File("C:\\nikos7\\Pictures\\photo.jpg"));
//enable MTOM
BindingProvider bindingProvider = (BindingProvider) imageServer;
SOAPBinding sopadBinding = (SOAPBinding) bindingProvider.getBinding();
sopadBinding.setMTOMEnabled(true);
String serverStatus = imageServer.uploadImage(imageToUpload);
System.out.println("Server returned Status : " + serverStatus);
}
}The above program reads the wsdl file of the published Web Service. In the download part, the client sends the name of the image to be downloaded to the server. The server responds with the Image and the client creats a simple JFrame to display it. In the upload part, the client reads an image from his file system and sends it to the server. On the other side, the server will simply store the image to his file system and the upload proccess is completed.
The output of the above program would be:
Server returned Status : Upload CompleteThis was an example on JAX-WS Attachment With MTOM. Download the Eclipse Project of this tutorial : JAX-WS-MTOM.zip
