Welcome to the Java Web Services Tutorial. Here we will learn about web services, useful concepts in web services and then different types of API we have in Java to create web services.
In simple words, services that can be accessed over network are called web services. So how does it differ from web application, they are also services that are accessed over network. There are few attributes that clarifies this difference.
I hope above differences are good enough to clear any confusion with web applications and web services. Both are different concepts and meant for different purpose.
There are two types of web services.
Java provides it’s own API to create both SOAP as well as REST web services.
Both of these APIs are part of standard JDK installation, so we don’t need to add any jars to work with them. Both of these APIs use annotations very heavily.
Let’s create a very simple Hello World JAX-WS application. TestService.java
package com.journaldev.jaxws.service;
import javax.jws.WebMethod;
import javax.jws.WebService;
import javax.jws.soap.SOAPBinding;
import javax.xml.ws.Endpoint;
@WebService
@SOAPBinding(style = SOAPBinding.Style.DOCUMENT)
public class TestService {
@WebMethod
public String sayHello(String msg){
return "Hello "+msg;
}
public static void main(String[] args){
Endpoint.publish("https://localhost:8888/testWS", new TestService());
}
}
That’s it. Just run this application and our Hello World JAX-WS SOAP web service is published. Below image shows the invocation of this JAX-WS web service through SOAP UI. That’s it for a very basic tutorial of JAX-WS web service. Below are some of the articles you should read for better understanding of SOAP web services and JAX-WS.
Jersey is the reference implementation of JAX-RS API, it’s not part of standard JDK and we have to include all the required jars. Best way is to use Maven build, so create a simple Dynamic web project and then convert it to Maven in Eclipse. Here is the final pom.xml file having required dependencies.
<project xmlns="https://maven.apache.org/POM/4.0.0" xmlns:xsi="https://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="https://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>JAX-RS-HelloWorld</groupId>
<artifactId>JAX-RS-HelloWorld</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>war</packaging>
<dependencies>
<dependency>
<groupId>com.sun.jersey</groupId>
<artifactId>jersey-server</artifactId>
<version>1.19</version>
</dependency>
<dependency>
<groupId>com.sun.jersey</groupId>
<artifactId>jersey-servlet</artifactId>
<version>1.19</version>
</dependency>
</dependencies>
<build>
<sourceDirectory>src</sourceDirectory>
<plugins>
<plugin>
<artifactId>maven-war-plugin</artifactId>
<version>2.6</version>
<configuration>
<warSourceDirectory>WebContent</warSourceDirectory>
<failOnMissingWebXml>false</failOnMissingWebXml>
</configuration>
</plugin>
<plugin>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.3</version>
<configuration>
<source>1.7</source>
<target>1.7</target>
</configuration>
</plugin>
</plugins>
</build>
</project>
Now add Jersey servlet to our deployment descriptor web.xml as front controller.
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="https://www.w3.org/2001/XMLSchema-instance"
xmlns="https://xmlns.jcp.org/xml/ns/javaee"
xsi:schemaLocation="https://xmlns.jcp.org/xml/ns/javaee https://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
id="WebApp_ID" version="3.1">
<display-name>JAX-RS-HelloWorld</display-name>
<servlet>
<servlet-name>Jersey REST Service</servlet-name>
<servlet-class>com.sun.jersey.spi.container.servlet.ServletContainer</servlet-class>
<init-param>
<param-name>com.sun.jersey.config.property.packages</param-name>
<param-value>com.journaldev.jaxrs.service</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>Jersey REST Service</servlet-name>
<url-pattern>/*</url-pattern>
</servlet-mapping>
</web-app>
Above two steps are required for initial setup, below is our Hello World JAX-RS service class.
package com.journaldev.jaxrs.service;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
@Path("/test")
public class TestService {
@GET
@Path("/hello/{msg}")
public String sayHello(@PathParam(value="msg") String msg){
return "Hello "+msg;
}
}
Just export it as WAR file and then access it in the browser as shown in below image. You can change the last part of URL and returned message will change accordingly. You can see how easy it was to create RESTful web service using JAX-RS API. However there is more to it, follow below articles to learn more.
That’s all for a quick introduction of java web services, finally if you are preparing for any interview then go through Web Services Interview Questions. References: JAX-WS Oracle Page, JAX-RS Oracle Page
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Eclipse gives me an error when I try to import javax.jws.WebService; Was this removed in later Java versions? What version / Edition of Java should I be using? Is there a new module for WebServices in Java? Thanks.
- Nikolai
Tutorial are best but few drawback still here 1) Explain in proper way with diagram, how to execute SOAP and Rest API, which tool /IDE need to use to develop SOAP and REST api with screenshort.
- munish sharma
I test Hello World JAX-WS Application by Intellij. But the web of “https://localhost:8888/testWS?wsdl” always display 404 error as below: Do you know how to solve this problem? HTTP Status 404 – Not Found Type Status Report Message /testWS Description The origin server did not find a current representation for the target resource or is not willing to disclose that one exists. Apache Tomcat/9.0.13
- Akira Chen
Hi Pankaj, could you please add the tutorials for securing the rest and soap webservices.
- Madhu