Category Archives: Programming

How to compare Strings in Java and more about Strings

Yes, I will be talking about one of the favorite topics or maybe the most argued topic of strings in programming languages. This post will cover how to use strings in Java.

Question

One of the beginner questions in Java is how to compare Strings in java?

Solution

The short answer is .equals compare the values of two strings and see if they are equal or not. Operator == compare the two string objects and see if they are referring to the same memory address.

Example:

String str1 = new String("test");

String str2 = new String("test");

str1.equals(str2) - This will return true.

str1 == str2 - This will return false.

 

Comment

Despite Java supports operator == for strings, it is not used for string comparison often. Object reference checks happen rarely. Another anomaly to this is if two strings are null.

Example:

String str1 = null;

String str2 = null;

str1 == str2 - this will return true.

str1.equals(str2) - this will throw null pointer exception (NPE).

Java offers another method called compareTo for String comparison. This can be used in following way

Example:

String str1 = "test";

String str2 = "test";

str1.compareTo(str2) == 0 - This will return true.

 

More about Strings

We all have seen StringBuffer, StringBuilder, StringWriter, StringTokenizer or just plain String. What are all these different aspects of String and when to use? Isn’t this too much to know when you just want to use a simple String object. This post will cover some information about all these different classes that Java offers.

StringBuffer

StringBuffers are thread-safe, they are just synchronized version of StringBuilder. StringBuffer offers some helpful methods like append and reverse.

Example:

StringBuffer sb = new StringBuffer();

sb.append("first string");

sb.toString();

 

StringBuilder

StringBuilder is not thread-safe, but they offer better performance than StringBuffer. You can say StringBuffer is thread-safe version of StringBuilder.

StringTokenizer

StringTokenizer is completely different from StringBuffer and StringBuilder as it is mainly used for splitting strings into token at a delimiter. StringBuffer and StringBuilder are used to build strings.

StringWriter

StringWriter is a character stream that collects the output in a string buffer. In short, you can say it uses StringBuffer underneath. This is an IO stream, very similar to File IO, but you can still access StringWriter even after stream has been closed.

Example:

StringWriter sw = new StringWriter();

sw.write("this is first string");

sw.toString();

 

Conclusion

In this article, we showed String comparison and different forms of String building. If you enjoyed this post, subscribe to my blog. If you want to read more about Strings, you can read here.

 

How to consume OAuth secured SOAP Webservice

I faced this issue where I had to consume a SOAP service which was secured by OAuth1.0a. And Spring doesn’t provide any direct solution for consuming OAuth secured SOAP webservice.

In Producing and Consuming SOAP web service and Consuming SOAP web service over HTTPS, we saw how to consume a SOAP web service. In this post, we will go little beyond this and implement a solution to consume OAuth secured SOAP web service. Securing a web service is a general trend and you must secure a web service if you are letting others consume it. This is a secure way to transfer data between producer and consumer without compromising customer data.

Pre-requisites

  1. Spring web services
  2. OAuth library and knowledge

How to implement it?

Firstly, below is a code that shows how to send a SOAP request call to a web service if it is not OAuth secured.


public class UserClient extends WebServiceGatewaySupport
{
   public GetUserResponse getUserById (int userid)
   {
      GetUserRequest userrequest = new GetUserRequest();
      userrequest.setId(userid);
      GetUserResponse response = (GetUserResponse)getWebServiceTemplate().marshalSendAndReceive(userrequest, new 
       SoapActionCallback("https://localhost:8443/benefits/endpoints/getUserResponse"));
      return response;
   }
}

We are using a WebServiceTemplate to marshal a request and send it to a SOAP endpoint. SoapActionCallback is a callback which allows changing the marshalled message and sends to an endpoint and then it will retrieve a response.

Secondly, as part of this solution, we will implement a class SignedMessageSender that will sign the request with OAuth consumer key and secret.


public class SignedMessageSender extends HttpComponentsMessageSender
{
   private final CommonsHttpOAuthConsumer consumer;

   public SignedMessageSender(CommonsHttpOAuthConsumer consumer)
   {
     this.consumer = consumer;
   }

   public WebServiceConnection createConnection(URI uri)
   {
     HttpComponentsConnection conn = null;
     try
     {
       conn = (HttpComponentsConnection)super.createConnection(uri);
       consumer.sign(connection.getHttpPost());
     }
     catch (IOException e | OAuthException e)
     {
      throw new RuntimeException("I/O Error", e);
     }
    return conn;
  }
}

Now we build our bean for the client to use this message sender. Then we will assign a consumer key and consumer secret. This also uses JAXB marshaller. The code for this will look like below


@Bean
public UserClient getUserClient(Jaxb2Marshaller marshaller)
{
   UserClient us = new UserClient();
   us.setDefaultUri("https://localhost:8443/benefits/endpoints/users.wsdl");
   us.setMarshaller(marshaller);
   us.setUnmarshaller(marshaller);
   String consumerkey = "";
   String secretkey = "";
   CommonsHttpOAuthConsumer consumer = new CommonsHttpOAuthConsumer(consumerkey,secretkey);
   SignedMessageSender signedMessageSender = new SignedMessageSender(consumer);
   signedMessageSender.createConnection(new URL("https://localhost:8443/benefits/endpoints/users.wsdl").toURI());
   us.setMessageSender(signedMessageSender);
   return us;
}

This shows how we can implement a solution to consume a SOAP web service secured with OAuth 1.0a. I am sure we can add a similar solution if the service producer secures it with OAuth 2.0, but that will be another post.

Conclusion

In conclusion, I showed how to send OAuth signed SOAP message to SOAP webservice.

References

  1. Add Header to SOAP message
  2. SOAP WS-addressing
  3. https://www.avisi.nl/blog/2012/11/22/consuming-oauth-secured-soap-webservices-using-spring-ws-axiom-signpost/

Guidelines to avoid null check statements

If you are tired of seeing NullPointer Exception, you are not alone. In this post, I show some guidelines to avoid null check. Have you ever seen code like below?

Object obj = anotherobj.getObject();
if(obj != null)
{
    // do something with obj
}

Imagine if you have to write such if-statement block for every object or variable you retrieve from different contract objects in your code, it would make the code cumbersome and unreadable. Also, it gives an impression of the naivety of developers in such cases.

I am writing this post based on a heavy discussion happening on StackOverflow Avoiding Null Statements. I am only using this post as a reference and writing my own guidelines based on my own experience. Answers to that post on StackOverflow are worth to checkout.

Guidelines to avoid checking null statements

  1. If callee keeps a contract of never returning a null, then the caller doesn’t have to add any check statement for a null value. But this is the basic premise a developer should follow when writing methods.
  2. Most of the time, the issue is not method returning null, but the logic implemented in these methods is not accurate. If the business logic of a method knows a way to handle errors in cases when it can return the right data, it should return an error instead of returning null.
public String getEmployeeInformation(String empcode)
{
   if (empcode == null)
   {
     // instead of returning null, throw an error
      throw new IllegalArgumentException(" empcode is null ");
   }
}

3.  Java 8 offers a new keyword optional 

public Optional<Employee> getEmployeeInfoWithSSN(String ssn) 
{ 
  .............. 
}

 

So if the employee information with particular SSN is not found, then the caller of this method has to explicitly think about the type system.

4.  Intellij Idea offers Java annotations like `Nullable` and `NotNull` 

5.  Write junit test cases for your classes which check for `assertNotNull()`

6.  Java 7 offers a utility method for Objects , Objects.requireNonNull();

Conclusion

In this post, I showed guidelines to avoid null check. Once you use these strategies, you make your life as a programmer way easier.

References

  1. Avoid null check statements
  2. Optional keyword

 

 

Consuming a SOAP Webservice over HTTPS

In the previous post, we talked about producing and consuming a SOAP web service here. This post will be a sequel to that post since recently I faced a similar issue during my project. In this post, we will talk about how to consume a SOAP Webservice over HTTPS. Since this will be a small post, we will not be posting any code on GitHub.

Problem –

While consuming a SOAP web service which is behind SSL, if you don’t handle SSL certificates, you will run into the following error


sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
at sun.security.validator.PKIXValidator.doBuild(PKIXValidator.java:387)
at sun.security.validator.PKIXValidator.engineValidate(PKIXValidator.java:292)
at sun.security.validator.Validator.validate(Validator.java:260)
at sun.security.ssl.X509TrustManagerImpl.validate(X509TrustManagerImpl.java:324)
at sun.security.ssl.X509TrustManagerImpl.checkTrusted(X509TrustManagerImpl.java:229)
at sun.security.ssl.X509TrustManagerImpl.checkServerTrusted(X509TrustManagerImpl.java:124)
at sun.security.ssl.ClientHandshaker.serverCertificate(ClientHandshaker.java:1351)
at sun.security.ssl.ClientHandshaker.processMessage(ClientHandshaker.java:156)
at sun.security.ssl.Handshaker.processLoop(Handshaker.java:925)
at sun.security.ssl.Handshaker.process_record(Handshaker.java:860)
at sun.security.ssl.SSLSocketImpl.readRecord(SSLSocketImpl.java:1043)
at sun.security.ssl.SSLSocketImpl.performInitialHandshake(SSLSocketImpl.java:1343)
at sun.security.ssl.SSLSocketImpl.writeRecord(SSLSocketImpl.java:728)
at sun.security.ssl.AppOutputStream.write(AppOutputStream.java:123)
at sun.security.ssl.AppOutputStream.write(AppOutputStream.java:138)
at SSLPoke.main(SSLPoke.java:31)
Caused by: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
at sun.security.provider.certpath.SunCertPathBuilder.build(SunCertPathBuilder.java:145)
at sun.security.provider.certpath.SunCertPathBuilder.engineBuild(SunCertPathBuilder.java:131)
at java.security.cert.CertPathBuilder.build(CertPathBuilder.java:280)
at sun.security.validator.PKIXValidator.doBuild(PKIXValidator.java:382)
... 15 more

 

Solution –

Basically this error is happening if your SOAP web service is on SSL and the client is trying to connect to web service, web service doesn’t recognize the client and throws this error.

To resolve this error, you can download an SSL certificate from the server where you are hosting the SOAP web service and import that certificate on your client machine’s Keystore. In a production environment, you should have a way to access this Keystore when a call is made to the web service.

Let’s assume that our web service from the post is on SSL, like https://localhost:8943/benefits/endpoints/users.wsdl. If you access this URL in the browser, you will be able to see the SSL certificate. Export this SSL certificate in base 64 format file, example sslcertificate.crt. Import this certificate in

keytool -import -alias sslcertificateofserver -keystore truststore.jks -storepass changeit -file sslcertificate.crt

Now, we will change the configuration class we wrote to configure web service components.


package com.betterjavacode.benefits.views;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.oxm.jaxb.Jaxb2Marshaller;

@Configuration
public class ClientAppConfig
{
   private Resource getKeyStore()
   {
     Environment.getProperty("betterjavacode.com.keystore");
   }

   private String getKeystorePassword()
   {
     Environment.getProperty("betterjavacode.com.keyStorePassword");
   }

   @Bean
   public Jaxb2Marshaller marshaller()
   {
     Jaxb2Marshaller marshaller = new Jaxb2Marshaller();
     marshaller.setContextPath("com.betterjavacode.benefits.soap");
     return marshaller;
   }

   @Bean
   public UserClient userClient(Jaxb2Marshaller marshaller) 
   {
     // WSDL URL - http://localhost:8080/benefits/endpoints/users.wsdl
     UserClient uc = new UserClient();
     uc.setDefaultUri("http://localhost:8080/benefits/endpoints/users.wsdl");
     uc.setMarshaller(marshaller);
     uc.setUnmarshaller(marshaller);

     FileInputStream fis = new FileInputStream(getKeyStore());
     KeyStore ks = KeyStore.getInstance("JKS");
     ks.load(fis, getKeyStorePassword().toCharArray());

     try 
     {
       fis.close();
     } 
     catch (IOException e) 
     {
     }
     KeyManagerFactory keyManagerFactory = KeyManagerFactory.getInstance(KeyManagerFactory.getDefaultAlgorithm());
     keyManagerFactory.init(ks, keyStorePassword.toCharArray());

     FileInputStream fisTS = new FileInputStream(getKeyStore());
     KeyStore ts = KeyStore.getInstance("JKS");
     ts.load(fisTS, trustStorePassword.toCharArray());

     try 
     {
       fisTS.close();
     } 
     catch(IOException e) 
     {
     }
     TrustManagerFactory trustManagerFactory = TrustManagerFactory.getInstance(TrustManagerFactory.getDefaultAlgorithm());
     trustManagerFactory.init(ts);

     HttpsUrlConnectionMessageSender messageSender = new HttpsUrlConnectionMessageSender();
     messageSender.setKeyManagers(keyManagerFactory.getKeyManagers());
     messageSender.setTrustManagers(trustManagerFactory.getTrustManagers());

     HostNameVerifier hv = new HostNameVerifier(){
        @Override
        public boolean verify( String hostname, SSLSession session)
        {
          return true;
        }
     }
     messageSender.setHostnameVerifier(hv);
     uc.setMessageSender(messageSender);
     return uc;
  } 
}

This change should fix the error about PKIX path building failed.

Conclusion –

In conclusion, we showed how to consume a SOAP Webservice over HTTPS by adding Keystore and Truststore check during runtime.

References

Producing and Consuming SOAP Webservice with Spring Boot – Part V

In this post, we will describe how to create a SOAP webservice from our existing Spring Boot REST API. In the last few posts, we have covered the following

  1. Spring Boot REST CRUD API – Part I
  2. Swagger Documentation for Spring Boot REST API – Part II
  3. Error Handling and logging in Spring Boot REST API – Part III
  4. Consuming RESTful Webservice – Part IV

This SOAP webservice will provide us user data from the database which is we have connected through Spring-data in Spring REST API.

1. Requirements

  1. Eclipse Mars2
  2. Maven 3.1 and above
  3. Spring 1.4 and above
  4. Java 7
  5. Tomcat 8

2. SOAP Web Service

We will use our existing Spring Boot REST API to build an application that will act as a SOAP web service to provide users data. For a given user id, web service will return user data.

Let’s create a schema file in src/main/resources directory and maven will create java classes based on this schema file.


<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:tns="https://betterjavacode.com/benefits/soap" targetNamespace="https://betterjavacode.com/benefits/soap" elementFormDefault="qualified">
	<xs:element name="getUserRequest">
		<xs:complexType>
			<xs:sequence>
				<xs:element name="id" type="xs:int"/>
			</xs:sequence>
		</xs:complexType>
	</xs:element>
	<xs:element name="getUserResponse">
		<xs:complexType>
			<xs:sequence>
				<xs:element name="user" type="tns:user"/>
			</xs:sequence>
		</xs:complexType>
	</xs:element>
	<xs:complexType name="user">
		<xs:sequence>
			<xs:element name="id" type="xs:int"/>
			<xs:element name="firstname" type="xs:string"/>
			<xs:element name="middlename" type="xs:string"/>
			<xs:element name="lastname" type="xs:string"/>
			<xs:element name="username" type="xs:string"/>
			<xs:element name="createdate" type="xs:date"/>
			<xs:element name="jobtitle" type="xs:string"/>
			<xs:element name="email" type="xs:string"/>
		</xs:sequence>
	</xs:complexType>
</xs:schema>

 

3. Update Maven dependencies

Now to generate classes from schema, we have to make sure we have all the right dependencies in our pom.xml. We will also add spring boot service dependency to create a SOAP web service.


<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
 <modelVersion>4.0.0</modelVersion>
 <groupId>com.betterjavacode</groupId>
 <artifactId>Benefits</artifactId>
 <packaging>war</packaging>
 <version>0.0.1-SNAPSHOT</version>
 <name>Benefits Maven Webapp</name>
 <url>http://maven.apache.org</url>
 <parent>
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-starter-parent</artifactId>
 <version>1.4.2.RELEASE</version>
 </parent>
 <dependencies>
 <dependency>
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-starter-web</artifactId>
 </dependency>
<dependency>
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-starter-data-jpa</artifactId>
 </dependency>
 <dependency>
 <groupId>mysql</groupId>
 <artifactId>mysql-connector-java</artifactId>
 <scope>runtime</scope>
 </dependency>
 <dependency>
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-starter-jdbc</artifactId>
 </dependency>
 <dependency>
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-starter-test</artifactId>
 </dependency>
 <dependency>
 <groupId>org.slf4j</groupId>
 <artifactId>slf4j-api</artifactId>
 </dependency>
 <dependency>
 <groupId>io.swagger</groupId>
 <artifactId>swagger-jersey2-jaxrs</artifactId>
 <version>1.5.12</version>
 </dependency>
 <dependency>
 <groupId>io.springfox</groupId>
 <artifactId>springfox-swagger2</artifactId>
 <version>2.6.1</version>
 <scope>compile</scope>
 </dependency>
 <dependency>
 <groupId>io.springfox</groupId>
 <artifactId>springfox-swagger-ui</artifactId>
 <version>2.6.1</version>
 <scope>compile</scope>
 </dependency>
 <dependency>
 <groupId>org.apache.logging.log4j</groupId>
 <artifactId>log4j-api</artifactId>
 </dependency>
 <dependency>
 <groupId>org.apache.logging.log4j</groupId>
 <artifactId>log4j-core</artifactId>
 </dependency>
 <dependency>
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-starter-web-services</artifactId>
 </dependency>
 <dependency>
 <groupId>wsdl4j</groupId>
 <artifactId>wsdl4j</artifactId>
 </dependency>
 <dependency>
 <groupId>javax.xml.bind</groupId>
 <artifactId>jaxb-api</artifactId>
 <version>2.1</version>
 </dependency>
 <dependency>
 <groupId>junit</groupId>
 <artifactId>junit</artifactId>
 <scope>test</scope>
 </dependency>
 </dependencies>
 <build>
 <plugins>
 <plugin>
 <artifactId>maven-compiler-plugin</artifactId>
 <version>3.3</version>
 <configuration>
 <source>1.8</source>
 <target>1.8</target>
 </configuration>
 </plugin>
 <plugin>
 <artifactId>maven-war-plugin</artifactId>
 <version>2.6</version>
 <configuration>
 <warSourceDirectory>WebContent</warSourceDirectory>
 <failOnMissingWebXml>false</failOnMissingWebXml>
 </configuration>
 </plugin>
 <plugin>
 <groupId>org.codehaus.mojo</groupId>
 <artifactId>jaxb2-maven-plugin</artifactId>
 <version>1.6</version>
 <executions>
 <execution>
 <id>xjc</id>
 <goals>
 <goal>xjc</goal>
 </goals>
 </execution>
 </executions>
 <configuration>
 <schemaDirectory>${project.basedir}/src/main/resources/</schemaDirectory>
 <outputDirectory>${project.basedir}/src/main/java</outputDirectory>
 <clearOutputDir>false</clearOutputDir>
 <schemaLanguage>WSDL</schemaLanguage>
 <generatePackage>com.betterjavacode.benefits.soap</generatePackage>
 <forceRegenerate>true</forceRegenerate>
 <scehmas>
 <schema>
 <url>http://localhost:8080/benefits/endpoints/users.wsdl</url>
 </schema>
 </scehmas>
 </configuration>
 </plugin>
 </plugins>
 <finalName>Benefits</finalName>
 </build>
 </project>

 

If we run the project with maven build now, the plugin jaxb2-maven-plugin will generate classes under com.betterjavacode.benefits.soap directory. It will also enable our wsdl SOAP url for users. This will generate following java objects

  • GetUserRequest
  • GetUserResponse
  • ObjectFactory
  • package-info
  • User

4. Defining the service

Next, we will define an interface for our service. This will look like below


package com.betterjavacode.benefits.services;

public interface UserAccountService
{
    public com.betterjavacode.benefits.soap.user.getUserDetails(int id);
}

Implementation of this service will be mapping out entity class User to generated class for soap service User. Using the id as a key to get user data from repository, we will map to soap service user. For post purposes, we will not show the implementation of this interface.

5. Creating the Service Endpoint

What is a service endpoint? When a SOAP request for defined URL is handled by Spring servlet, Spring servlet redirects that request to service endpoint. Service endpoint then processes that request to create a response. Our spring-boot-starter-web-services dependency will bring all the necessary classes for annotation purposes.


package com.betterjavacode.benefits.services.endpoints; 

import org.springframework.beans.factory.annotation.Autowired; 
import org.springframework.ws.server.endpoint.annotation.Endpoint; 
import org.springframework.ws.server.endpoint.annotation.PayloadRoot; 
import org.springframework.ws.server.endpoint.annotation.RequestPayload; 
import org.springframework.ws.server.endpoint.annotation.ResponsePayload; 
import com.betterjavacode.benefits.services.UserAccountService; 
import com.betterjavacode.benefits.soap.GetUserRequest; 
import com.betterjavacode.benefits.soap.GetUserResponse; 
import com.betterjavacode.benefits.soap.User; 

@Endpoint 
public class UserAccountServiceEndpoint 
{ 
  // private static final String TARGET_NAMESPACE ="http://com/betterjavacode/benefits/webservices/useraccountservice";  
  private static final String TARGET_NAMESPACE =   "https://betterjavacode.com/benefits/soap"; 
  @Autowired private UserAccountService userAccountService; 
  @PayloadRoot(localPart = "getUserRequest", namespace = TARGET_NAMESPACE) 

  public @ResponsePayload GetUserResponse getUserRequest(@RequestPayload    GetUserRequest request) 
  {  
     GetUserResponse response = new GetUserResponse(); 
     User user = userAccountService.getUserDetails(request.getId()); 
     response.setUser(user); 
     return response; 
   } 
}

@Endpoint annotation allows the class to be defined as service endpoint and included in @Component annotation for scanning. Make sure the namespace defined in this class matches with XSD schema definition. Otherwise, you can run into error for “No Endpoint defined for“.

6. Configuration

Next, we will configure our configuration class to generate wsdl endpoint. This configuration class will be annotated by @EnableWs to provide web service configuration.


package com.betterjavacode.benefits;

import org.springframework.boot.web.servlet.ServletRegistrationBean;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.ClassPathResource;
import org.springframework.ws.config.annotation.EnableWs;
import org.springframework.ws.config.annotation.WsConfigurerAdapter;
import org.springframework.ws.transport.http.MessageDispatcherServlet;
import org.springframework.ws.wsdl.wsdl11.DefaultWsdl11Definition;
import org.springframework.xml.xsd.SimpleXsdSchema;
import org.springframework.xml.xsd.XsdSchema;

@Configuration
@EnableWs
@ComponentScan("com.betterjavacode")
public class AppConfig extends WsConfigurerAdapter
{

    @Bean
	public ServletRegistrationBean messageDispatcherServlet(ApplicationContext applicationContext)
	{
		MessageDispatcherServlet servlet = new MessageDispatcherServlet();
		servlet.setApplicationContext(applicationContext);
		return new ServletRegistrationBean(servlet,"/benefits/endpoints/*");
	}

	@Bean(name="users")
	public DefaultWsdl11Definition defaultWsdl11Definition(XsdSchema usersSchema)
	{
		DefaultWsdl11Definition wsdl11definition = new DefaultWsdl11Definition();
		wsdl11definition.setPortTypeName("UserAccountService");
		wsdl11definition.setLocationUri("/endpoints");
		wsdl11definition.setTargetNamespace("http://com/betterjavacode/benefits/webservices/useraccountservice");
		wsdl11definition.setSchema(usersSchema);
		return wsdl11definition;
	}

	@Bean
	public XsdSchema usersSchema()
	{
		return new SimpleXsdSchema(new ClassPathResource("employees.xsd"));
	}
}

Few important points about this configuration class are

  • MessageDispatcherServlet is a required servlet to dispatch web service messages. We set this servlet with a bean to handle the URL from which request will be coming.
  • DefaultWsdl11Definition creates SOAP for the given XSD schema
  • XsdSchema provides an abstraction for our users XSD schema

7. Running the SOAP Webservice

Now build our project with maven. Run the spring boot application through eclipse to start the embedded tomcat server. Once the tomcat server starts, if we access url http://localhost:8080/benefits/endpoints/users.wsdl

Output in the browser will be as below

SOAP Webservice - wsdl endpoint

Here we showed how to create a simple SOAP webservice which we have combined with Spring Boot REST API service. We can also test this SOAP webservice using Soap UI, as shown in below screenshot

SOAP Webservice - SoapUITest

8. Consuming the SOAP web service

In previous steps, we showed how to produce a SOAP web service, now we will show how to consume this SOAP web service programmatically.

8.1 Create a client class

Under package com.betterjavacode.benefits.views, define a class UserClient which will extend a WebServiceGatewaySupport class. WebServiceGatewaySupport class provides web service methods.


package com.betterjavacode.benefits.views; 

import org.springframework.ws.client.core.support.WebServiceGatewaySupport; 
import org.springframework.ws.soap.client.core.SoapActionCallback; 
import com.betterjavacode.benefits.soap.GetUserRequest; 
import com.betterjavacode.benefits.soap.GetUserResponse; 

public class UserClient extends WebServiceGatewaySupport 
{

   public GetUserResponse getUserById(int userid) 
   { 
      GetUserRequest userrequest = new GetUserRequest(); userrequest.setId(userid); 
      GetUserResponse response = (GetUserResponse) getWebServiceTemplate().marshalSendAndReceive(userrequest, new SoapActionCallback("http://localhost:8080/benefits/endpoints/getUserResponse"));  
      return response;  
    }  
}

8.2 Configure the client for Spring Bean support

We will configure Jaxb2Marshaller to support JAXB to set context path. This will help us marshal and unmarshal our xml request and response through.


package com.betterjavacode.benefits.views; 

import org.springframework.context.annotation.Bean; 
import org.springframework.context.annotation.Configuration; 
import org.springframework.oxm.jaxb.Jaxb2Marshaller; 

@Configuration 
public class ClientAppConfig 
{ 

   @Bean 
   public Jaxb2Marshaller marshaller() 
   {  
       Jaxb2Marshaller marshaller = new Jaxb2Marshaller(); 
       marshaller.setContextPath("com.betterjavacode.benefits.soap"); 
       return marshaller;  
    } 
    
    @Bean 
    public UserClient userClient(Jaxb2Marshaller marshaller)  
    {  
        // WSDL URL - http://localhost:8080/benefits/endpoints/users.wsdl 
        UserClient uc = new UserClient(); 
        uc.setDefaultUri("http://localhost:8080/benefits/endpoints/users.wsdl"); 
        uc.setMarshaller(marshaller);  
        uc.setUnmarshaller(marshaller);
        return uc; 
     }  
}

8.3 Run the SOAP web service client

We will define a class with the main method to pass an argument of user id. Our client will call the web service with a passed argument to return the data if that user id exists in the database.

9. Conclusion

In this article, we showed how to create a SOAP web service and how to build a client to consume the same SOAP web service using Spring Boot. The code for this is available at github

10. References

  1. Spring Web services tutorial
  2. SOAP Web service producer and consumer
  3. Consuming a web service in java and SOAP UI