In this article, we will learn and implement JAX-RS Restful web service which is exposed to upload/download MS Word document
JBoss RestEasy is a JAX-RS implementation for developing Restful web service in java. Once developed, it isn’t restricted to deploy only in JBoss Application Server but you can deploy in any other server like Apache Tomcat, Glassfish, Oracle Weblogic, etc
Download
- Annotate download MS Word document method with @Produces(“application/msword”)
- Set “Content-Disposition” in the ResponseBuilder to allow downloading users to select path to download MS Word document file
- Finally, build() the ResponseBuilder and return Response object with “download success” message
Upload
- Annotate upload method with @Consumes(“multipart/form-data”)
- Get MultipartFormDataInputand and process inputParts to get headers and inputstreams
- Finally, write the steams to the upload file server using basic file handling operations
- Return “upload success” message within Response object
Annotation Used
- @Path (ws.rs.Path)
- @GET (ws.rs.GET)
- @POST (ws.rs.POST)
- @Consumes (ws.rs.Consumes)
- @Produces (ws.rs.Produces)
- MediaType (ws.rs.core.MediaType)
Technology Used
- Java 1.7
- Eclipse Luna IDE
- RestEasy-3.0.8.Final
- Apache Maven 3.2.1
- Apache Tomcat 7.0.54
- JBoss Application Server 7.1.1.Final
Mavenize or download required jars
Add RestEasy-3.0.8.Final dependencies to pom.xml
<properties> <resteasy.version>3.0.8.Final</resteasy.version> <resteasy.scope>compile</resteasy.scope> <!-- compile(Tomcat) / provided(JBoss) --> <compileSource>1.7</compileSource> <maven.compiler.target>1.7</maven.compiler.target> <maven.compiler.source>1.7</maven.compiler.source> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> </properties> <dependencies> <!-- RESTEasy JAX RS Implementation --> <dependency> <groupId>org.jboss.resteasy</groupId> <artifactId>resteasy-jaxrs</artifactId> <version>${resteasy.version}</version> <scope>${resteasy.scope}</scope> </dependency> <!-- Resteasy Multipart Provider --> <dependency> <groupId>org.jboss.resteasy</groupId> <artifactId>resteasy-multipart-provider</artifactId> <version>${resteasy.version}</version> <scope>${resteasy.scope}</scope> </dependency> <!-- Resteasy Servlet Container Initializer --> <dependency> <groupId>org.jboss.resteasy</groupId> <artifactId>resteasy-servlet-initializer</artifactId> <version>${resteasy.version}</version> <scope>${resteasy.scope}</scope> </dependency> <!-- RESTEasy JAX RS Client --> <dependency> <groupId>org.jboss.resteasy</groupId> <artifactId>resteasy-client</artifactId> <version>${resteasy.version}</version> <scope>${resteasy.scope}</scope> </dependency> </dependencies>
Folks who aren’t familiar with Maven concepts or don’t require maven for their project, can download the below jars individually from the central repository or maven repository and download directly from Spring site include them in the classpath
- resteasy-jaxrs
- resteasy-multipart-provider
- resteasy-servlet-initializer
- resteasy-client
- resteasy-jaxb-provider
- jaxrs-api-3.0.8.Final
- jaxb-api-2.7.7
- jaxb-core-2.7.7
- jaxb-impl-2.7.7
- jboss-annotations-api_1.1_spec-1.0.1.Final
- jcp-annotations-1.0
- activation-1.1
- async-http-servlet-3.0-3.0.8.Final
- common-codec-1.6
- commons-io-2.1
- commons-logging-1.1.1
- httpcore-4.2.1
- httpclient-4.2.1
- jsr173_api-1.0
- FastInfoset-1.2.12
- istack-commons-runtime-2.16
- apache-mime4j-0.6
- mail-1.5.0-b01
Directory Structure
Before moving on, let us understand the directory/package structure once you create project in Eclipse IDE
Maven has to follow certain directory structure
- src/test/java –> test related files, mostly JUnit test cases
- src/main/java –> create java source files under this folder
- src/main/resources –> all configuration files placed here
- src/test/resources –> all test related configuration files placed here
- Maven Dependencies or Referenced Libraries –> includes jars in the classpath
- WEB-INF under webapp –> stores web.xml & other configuration files related to web application
Project Structure (Package Explorer view in Eclipse)
Jars Libraries Used in the Project (Maven Dependencies)
Web application
For any web application, entry point is web.xml which describes how the incoming http requests are served / processed. Further, it describes about the global-context and local-context param (i.e.; <context-param> & <init-param>) for loading files particular to project requirements & contains respective listener
With this introduction, we will understand how we configured web.xml for RestEasy JAX-RS Restful web service
web.xml (the entry point –> under WEB-INF)
This web.xml file describes,
- Like any JEE web framework register jboss.resteasy.plugins.server.servlet.HttpServletDispatcher with servlet container
- http requests with URL pattern “/resteasy/*” will be sent to the registered servlet called “ws.rs.core.Application” i.e.; HttpServletDispatcher (org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher)
- set servlet.mapping.prefix as <context-param>, if your servlet-mapping has a url-pattern anything other than “/*”. In this example, set “/resteasy”
- if not set, then you will end up with 404 not found error
- set resources as <param-name> with comma delimited list of fully qualified JAX-RS resource class names you want to register as <param-value> using global <context-param>
- <welcome-file-list> files under this tag is the start-up page
web.xml
<?xml version="1.0" encoding="UTF-8"?> <web-app version="3.0" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"> <display-name>RestEasy-UP-DOWN-Doc-File</display-name> <!-- RestEasy resource registering --> <context-param> <param-name>resteasy.resources</param-name> <param-value>com.resteasy.series.upload.download.service.FileServiceImpl</param-value> </context-param> <!-- RestEasy Servlet --> <servlet> <servlet-name>javax.ws.rs.core.Application</servlet-name> <servlet-class>org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher</servlet-class> </servlet> <servlet-mapping> <servlet-name>javax.ws.rs.core.Application</servlet-name> <url-pattern>/resteasy/*</url-pattern> </servlet-mapping> <!-- this is mandatory, if url-pattern is other than /* --> <context-param> <param-name>resteasy.servlet.mapping.prefix</param-name> <param-value>/resteasy</param-value> </context-param> <!-- welcome file --> <welcome-file-list> <welcome-file>index.html</welcome-file> </welcome-file-list> </web-app>
Let’s see coding in action
URL Pattern
Http url for any common web application is http://<server>:<port>/<root-context>/<from_here_application_specific_path>
In our example, we are going to deploy the war into Tomcat 7.0 server so our server and port are localhost and 8080 respectively. Context root is the project name i.e.; RestEasy-UP-DOWN-Doc-File. Initial path for this application is http://localhost:8080/RestEasy-UP-DOWN-Doc-File
We have configured “/resteasy/*” as url-pattern for the “javax.ws.rs.core.Application” servlet in web.xml and at interface-level (or say class-level) path configured is “/fileservice” using @Path annotation. Next respective path for each method annotated with @Path (method-level)
File Service interface
File service exposes two public methods one for downloading MS Word document and another for uploading file
Download MS Word document method annotated with @Produces(“application/msword”) and upload file method annotated with @Consumes(“multipart/form-data”)
NOTE: It’s always a good programming practice to do code-to-interface and have its implementation separately
IFileService.java
package com.resteasy.series.upload.download.service; import javax.ws.rs.Consumes; import javax.ws.rs.GET; import javax.ws.rs.POST; import javax.ws.rs.Path; import javax.ws.rs.Produces; import javax.ws.rs.core.MediaType; import javax.ws.rs.core.Response; import org.jboss.resteasy.plugins.providers.multipart.MultipartFormDataInput; @Path("/fileservice") public interface IFileService { // http://localhost:8080/RestEasy-UP-DOWN-Doc-File/resteasy/fileservice/download/doc - Tomcat 7.0.x // http://localhost:9090/RestEasy-UP-DOWN-Doc-File/resteasy/fileservice/download/doc - JBoss AS7 @GET @Path("/download/doc") @Produces("application/msword") public Response downloadDocFile(); // http://localhost:8080/RestEasy-UP-DOWN-Doc-File/resteasy/fileservice/upload/doc - Tomcat 7.0.x // http://localhost:9090/RestEasy-UP-DOWN-Doc-File/resteasy/fileservice/upload/doc - JBoss AS7 @POST @Path("/upload/doc") @Consumes(MediaType.MULTIPART_FORM_DATA) public Response uploadDocFile(MultipartFormDataInput multipartFormDataInput); }
File Service implementation
Implements above interface
Download
It’s quite straightforward, constructing file object supplying path location for the .docx file to be downloaded and setting this file object in ResponseBuilder and returning Response object
Upload
Iterate through each inputParts extracted from multiPartFormDataInput & get inputstreams and write to the UPLOAD_FILE_SERVER using simple file handling operations
FileServiceImpl.java
package com.resteasy.series.upload.download.service; import java.io.File; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.util.List; import java.util.Map; import javax.ws.rs.core.MultivaluedMap; import javax.ws.rs.core.Response; import javax.ws.rs.core.Response.ResponseBuilder; import org.jboss.resteasy.plugins.providers.multipart.InputPart; import org.jboss.resteasy.plugins.providers.multipart.MultipartFormDataInput; public class FileServiceImpl implements IFileService { public static final String UPLOAD_FILE_SERVER = "D:/Demo/upload/"; public Response downloadDocFile() { // set file (and path) to be download File file = new File("D:/Demo/download/Sample.docx"); ResponseBuilder responseBuilder = Response.ok((Object) file); responseBuilder.header("Content-Disposition", "attachment; filename=\"MyExcelFile.docx\""); return responseBuilder.build(); } public Response uploadDocFile(MultipartFormDataInput multipartFormDataInput) { // local variables MultivaluedMap<String, String> multivaluedMap = null; String fileName = null; InputStream inputStream = null; String uploadFilePath = null; try { Map<String, List<InputPart>> map = multipartFormDataInput.getFormDataMap(); List<InputPart> lstInputPart = map.get("uploadedFile"); for(InputPart inputPart : lstInputPart){ // get filename to be uploaded multivaluedMap = inputPart.getHeaders(); fileName = getFileName(multivaluedMap); if(null != fileName && !"".equalsIgnoreCase(fileName)){ // write & upload file to UPLOAD_FILE_SERVER inputStream = inputPart.getBody(InputStream.class,null); uploadFilePath = writeToFileServer(inputStream, fileName); // close the stream inputStream.close(); } } } catch(IOException ioe){ ioe.printStackTrace(); } finally{ // release resources, if any } return Response.ok("File uploaded successfully at " + uploadFilePath).build(); } /** * * @param inputStream * @param fileName * @throws IOException */ private String writeToFileServer(InputStream inputStream, String fileName) throws IOException { OutputStream outputStream = null; String qualifiedUploadFilePath = UPLOAD_FILE_SERVER + fileName; try { outputStream = new FileOutputStream(new File(qualifiedUploadFilePath)); int read = 0; byte[] bytes = new byte[1024]; while ((read = inputStream.read(bytes)) != -1) { outputStream.write(bytes, 0, read); } outputStream.flush(); } catch (IOException ioe) { ioe.printStackTrace(); } finally{ //release resource, if any outputStream.close(); } return qualifiedUploadFilePath; } /** * * @param multivaluedMap * @return */ private String getFileName(MultivaluedMap<String, String> multivaluedMap) { String[] contentDisposition = multivaluedMap.getFirst("Content-Disposition").split(";"); for (String filename : contentDisposition) { if ((filename.trim().startsWith("filename"))) { String[] name = filename.split("="); String exactFileName = name[1].trim().replaceAll("\"", ""); return exactFileName; } } return "UnknownFile"; } }
View Technologies
<table> element within <form> tag, on click of “Upload File” button invokes upload file service method which is configured in the action attribute
uploadDocFile.html
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> <title>RestEasy : File Upload</title> </head> <body> <center> <b>RestEasy : JAX-RS Restful web service Learning</b> <h4>Uploading files using JAX-RS Restful web service</h4> <div style="width: 400px; border: 1px solid blue; padding: 20px; text-align: center;"> <form method="post" action="resteasy/fileservice/upload/doc" enctype="multipart/form-data"> <table align="center" border="1" bordercolor="black" cellpadding="0" cellspacing="0"> <tr> <td>Select File:</td> <td><input type="file" name="uploadedFile" size="100" /></td> </tr> <tr> <td><input type="submit" value="Upload File" /></td> <td><input type="reset" value="Reset" /></td> </tr> </table> </form> </div> </center> </body> </html>
Deployment
- Run maven command to build the war: mvn clean install (use command prompt or integrated maven in eclipse IDE
- Copy the war file from the target folder
- Paste it into apache tomcat (webapps folder)
- Start the tomcat server
Test the service !!
Testing
There are many ways to do testing
- Access html page from web browser
- Copy the URL of GET service into web browser
- Advanced REST client from Google Chrome
- Rest client in Mozilla Firefox Add On
- Write your own client for example, Java client using improved CloseableHttpClient from Apache
- JDK’s in-built classes like HttpURLConnection
- Using Client, WebTarget from core JAX-RS classes javax.ws.rs.client
- Using ResteasyClient, ResteasyWebTarget and Response classes from JBoss package org.jboss.resteasy.client
- Using ClientRequest and ClientResponse classes from JBoss package org.jboss.resteasy.client
1. HTML page in web browser
1.1 upload file
Enter URL: http://localhost:8080/RestEasy-UP-DOWN-Doc-File/uploadDocFile.html
And select word document using file chooser
Click “Upload File”
Result in web browser: upload success
1.2 download word document
Enter URL: http://localhost:8080/RestEasy-UP-DOWN-Doc-File/resteasy/fileservice/download/doc into web browser
Allows downloading users to open/save word documen
2. Java client (RestEasy)
2.1 Upload word document
Uses ClientRequest and ClientResponse classes from JBoss RestEasy package org.jboss.resteasy.client for invoking Restful web service to upload .docx file
TestUploadFileService.java
package test.resteasy.series.upload.download.service; import java.io.File; import java.io.FileInputStream; import java.io.IOException; import javax.ws.rs.HttpMethod; import javax.ws.rs.core.MediaType; import org.jboss.resteasy.client.ClientRequest; import org.jboss.resteasy.client.ClientResponse; import org.jboss.resteasy.plugins.providers.multipart.MultipartFormDataOutput; public class TestUploadFileService { public static void main(String []args) throws Exception { // set file upload parameters String httpURL = "http://localhost:8080/RestEasy-UP-DOWN-Doc-File/resteasy/fileservice/upload/doc"; File filePath = new File("D:/Demo/download/Sample.docx"); String filename = "MyDocumentSample.docx"; // invoke file upload service using above parameters String responseString = testUploadService(httpURL, filePath, filename); System.out.println("responseString : " + responseString); } /** * using ClientRequest and ClientResponse classes from org.jboss.resteasy.client * @param httpURL * @return responseString * @throws IOException */ @SuppressWarnings({ "deprecation" }) public static String testUploadService(String httpURL, File filePath, String filename) throws IOException { // local variables ClientRequest clientRequest = null; ClientResponse<?> clientResponse = null; MultipartFormDataOutput multipartFormDataOutput = null; int responseCode; String responseMessageFromServer = null; String responseString = null; try{ // invoke service after setting necessary parameters clientRequest = new ClientRequest(httpURL); clientRequest.setHttpMethod(HttpMethod.POST); clientRequest.header("Content-Type", MediaType.MULTIPART_FORM_DATA); // set file upload values multipartFormDataOutput = new MultipartFormDataOutput(); multipartFormDataOutput.addFormData("uploadedFile", new FileInputStream(filePath), MediaType.MULTIPART_FORM_DATA_TYPE, filename); // set POST request body and invoke the service clientRequest.body(MediaType.MULTIPART_FORM_DATA_TYPE, multipartFormDataOutput); clientResponse = clientRequest.post(); // get response code responseCode = clientResponse.getResponseStatus().getStatusCode(); System.out.println("Response code: " + responseCode); if(clientResponse.getResponseStatus().getStatusCode() != 200) { throw new RuntimeException("Failed with HTTP error code : " + responseCode); } // get response message responseMessageFromServer = clientResponse.getResponseStatus().getReasonPhrase(); System.out.println("ResponseMessageFromServer: " + responseMessageFromServer); // get response string responseString = clientResponse.getEntity(String.class); } catch(Exception ex) { ex.printStackTrace(); } finally{ // release resources, if any clientResponse.close(); clientRequest.clear(); } return responseString; } }
Output in console (upload .docx file)
Response code: 200 ResponseMessageFromServer: OK responseString : File uploaded successfully at D:/Demo/upload/MyDocumentSample.docx
2.2 Download word document
Uses ClientRequest and ClientResponse classes from JBoss RestEasy package org.jboss.resteasy.client to invoke Restful web service to download .docx file
TestDownloadFileService.java
package test.resteasy.series.upload.download.service; import java.io.File; import java.io.FileWriter; import java.io.IOException; import javax.ws.rs.HttpMethod; import org.jboss.resteasy.client.ClientRequest; import org.jboss.resteasy.client.ClientResponse; public class TestDownloadFileService { public static final String DOWNLOAD_FILE_LOCATION = "D:/Demo/test/"; public static void main(String []args) throws IOException { String httpURL = "http://localhost:8080/RestEasy-UP-DOWN-Doc-File/resteasy/fileservice/download/doc"; String responseString = testDownloadService(httpURL); System.out.println("responseString : " + responseString); } /** * using ClientRequest and ClientResponse classes from org.jboss.resteasy.client * @param httpURL * @return responseString * @throws IOException */ @SuppressWarnings({ "deprecation" }) public static String testDownloadService(String httpURL) throws IOException { // local variables ClientRequest clientRequest = null; ClientResponse<?> clientResponse = null; File readSourceFile = null; File destinationFileLocation = null; FileWriter fileWriter = null; int responseCode; String responseMessageFromServer = null; String responseString = null; String qualifiedDownloadFilePath = null; try{ // invoke service after setting necessary parameters clientRequest = new ClientRequest(httpURL); clientRequest.setHttpMethod(HttpMethod.GET); clientRequest.header("accept", "application/msword"); clientResponse = clientRequest.get(); // get response code responseCode = clientResponse.getResponseStatus().getStatusCode(); System.out.println("Response code: " + responseCode); if(clientResponse.getResponseStatus().getStatusCode() != 200) { throw new RuntimeException("Failed with HTTP error code : " + responseCode); } // get response message responseMessageFromServer = clientResponse.getResponseStatus().getReasonPhrase(); System.out.println("ResponseMessageFromServer: " + responseMessageFromServer); // read response and store the image file at destination readSourceFile = (File) clientResponse.getEntity(File.class); qualifiedDownloadFilePath = DOWNLOAD_FILE_LOCATION + "MyDocumentFile.docx"; destinationFileLocation = new File(qualifiedDownloadFilePath); readSourceFile.renameTo(destinationFileLocation); fileWriter = new FileWriter(readSourceFile); fileWriter.flush(); // set download SUCCES message to return responseString = "downloaded successfully at " + qualifiedDownloadFilePath; } catch(Exception ex) { ex.printStackTrace(); } finally{ // release resources, if any clientResponse.close(); fileWriter.close(); clientRequest.clear(); } return responseString; } }
Output in console (download .docx file)
Response code: 200 ResponseMessageFromServer: OK responseString : downloaded successfully at D:/Demo/test/MyDocumentFile.docx
Download project (Tomcat Server 7.0.x)
RestEasy-UP-DOWN-Doc-File (Tomcat server) (12kB)
JBoss Deployment
- Update pom.xml with resteasy scope “provided” for dependencies as JBoss AS7 modules already contains these dependent jars
<resteasy.scope>provided</resteasy.scope> <!-- compile(Tomcat) / provided(JBoss) -->
- Update web.xml
web.xml<?xml version="1.0" encoding="UTF-8"?> <web-app version="3.0" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"> <display-name>RestEasy-UP-DOWN-Doc-File</display-name> <!-- RestEasy Servlet --> <servlet-mapping> <servlet-name>javax.ws.rs.core.Application</servlet-name> <url-pattern>/resteasy/*</url-pattern> </servlet-mapping> <!-- welcome file --> <welcome-file-list> <welcome-file>index.html</welcome-file> </welcome-file-list> </web-app>
- Rest remain the same
- Read through this article which explains development & deployment of RestEasy web service with JBoss Application Server in detail
Note: JBoss Application Server 7.1.1.Final comes with default RestEasy distribution with version 2.3.2.Final. So update JBoss AS7 with latest RestEasy version. Look at this article, which explains how to update default version with latest version available in the JBoss community
Download project (JBoss Application Server 7.1.1.Final)
RestEasy-UP-DOWN-Doc-File (JBoss server) (12kB)
Conclusion: It’s quite easy to implement download/upload files functionality in JAX-RS Restful web service using simple annotations like @Produces & @Consumes on top of the service class to be exposed
In the next article, very similarly we will implement an example for uploading/downloading Zip (.zip) files
Happy Coding !!
Happy Learning !!