Java Helps: Web Service

Showing posts with label Web Service. Show all posts

Javalin: A Tiny but Mighty Framework

Two years ago, I wrote an article Microservices in a minute using the open source framework MSF4J. Today I came across another framework Javalin: another lightweight framework to develop lightweight web applications with less or no effort. We already have plenty of web frameworks including the shining star Spring. What makes Javalin different is its simplicity. In addition, it can be used as a microservice framework or a tiny web framework to serve a web application with static files. In Javalin developers' words:

Javalin’s main goals are simplicity, a great developer experience, and first-class interoperability between Kotlin and Java.

Comparing Javalin with Spring is like comparing a shaving blade with a Wenger 16999 Swiss Army Knife Giant, but it does what it is supposed to do. If you want to quickly add a REST endpoint for a quick demo or if you just need a simple web framework without any additional gimmicks like Dependency Injection or Object Relational Mapping, consider Javalin. It is easy to learn and lighter to run.

In this article, you will see how to use Javalin as a web framework to serve a contact-us page and how to build a CRUD micro-service using Javalin.

Requirements:

Android Database Kotlin Web Web Service

Access MySQL from Android through RESTful Web Service

Gobinath 1:17:00 PM Add Comment

Gobinath

Finally, I found some time to write about accessing MySQL or any database that you can think about from an Android application. Android offers a built-in database known as SQLite which is supposed to be used for local data storage. For example, if you want to store your recent transactions locally in the device, you have to go with SQLite. I have already written a few articles on how to use SQLite database in Android. However, enterprise mobile applications often depend on client/server databases such as MySQL, Oracle DB or MongoDB. Whatever the database, you have chosen, the way to access them from an Android application is pretty same. In this article, I explain how to access a MySQL database from an Android application written in Kotlin.

I will use Kotlin for all upcoming Android tutorials because it is the future of Android programming. Kotlin is a JVM based language and you can easily convert a Kotlin project into Java and vice versa.

An Android application is not supposed to directly access a database deployed in a server. I do not recommend implementing JDBC connections in an Android application due to the tight coupling introduced between the application and the database. The industrial best practice requires you to implement a web service between the database and the Android application. Having a web service layer reduces the complexity of the Android application and also reduces the dependency on database specific operations. Therefore, the problem of accessing a client/server database like MySQL from an Android application can be defined as the problem of consuming a web service hosted somewhere.

Having said that, as an Android developer, you don't need to care about what is behind the web service. It may be a MySQL database, MongoDB database, a Social Media network or even a Weather Network API. What you need is the API endpoints exposed by the web service. In this article, I only explain how to connect to a web service hosted on your local machine from an Android application. However, the sample web service used in this article provides API endpoints to CRUD operations on a MySQL database. Please follow the RESTful CRUD With Java and MySQL in Minutes article and develop the web service to access a MySQL database. In the following section, you will learn how to access the web service you have created for accessing a database.

Database Frameworks Hibernate Java Web Service

RESTful CRUD With Java and MySQL in Minutes

Gobinath 10:35:00 AM 17 Comments

Gobinath

I keep receiving so many requests for an article on how to access MySQL database from Android application. Even though Android applications can have direct access to MySQL database server, that is not preferred due to security issues and high complexity. The easy and best solution is developing a REST web service to receive the requests from whatever the client (including Android applications) and execute them on the database connected with the web service.

There are so many articles already available on the Internet about how to create a web service to perform Create, Read, Update & Delete (CRUD) operations on a database and how to connect from an Android client. However, I wondered why most of them are using PHP to develop the web service! I believe developers find PHP a less painful language to develop web services than Java. In this article, I am going to show how to develop a RESTful CRUD Web service with Java in minutes. As a matured language Java has enough frameworks to make your task easy. I guarantee that you will never look back for a different language once you know the tools.

Prerequisite:

Eclipse IDE for Java EE or any Java IDE with Apache Maven support. (I recommend IntelliJ IDEA)
MySQL 5.x
PhpMyAdmin or any other clients to access MySQL database
Postman or any other REST Clients

Java Web Service WSO2

Microservices Framework for Java (MSF4J) - HelloWorld!

Gobinath 4:02:00 PM 1 Comment

Gobinath

In a recent article: Microservices in a minute, I introduced a lightweight microservice framework: WSO2 MSF4J. That tutorial shows you how to create a microservice in minutes using the Maven archetype. However, the libraries available in the public Maven repositories are bit older and there are new releases after MSF4J 2.0.1 which are available in WSO2's Maven repository. This article shows you how to create a microservice using the latest stable release of MS4J Framework.

Requirements:

Java Development Kit 1.8
Apache Maven 3.x
Postman or CURL
Eclipse IDE for Java EE Developers / Any IDEs with Maven support

Java Web Service WSO2

Microservices in a minute

Gobinath 11:41:00 AM Add Comment

Gobinath

Microservices get more light in recent years as a new service oriented architecture with a high level of modularity. Compared to traditional web services either they are SOAP or REST, microservices are small in size and complexity but brings the cohesiveness to web services. Microservices do not require a servlet container or web server to be deployed instead they are created as individual JAR files which you can run as any other JAR files. The idea behind microservices is creating tiny individual services which can be developed, deployed and modified with less effort. This article introduces microservices using WSO2 Microservices Framework in a minute.

Image Credits: http://wso2.com/blogs/thesource/2016/05/enabling-microservice-architecture-with-middleware/

WSO2 Microservices Framework for Java (WSO2 MSF4J) is a lightweight annotation based model to develop microservices in Java. Developers can create a microservice using just two or three classes which of course require a framework to take care of the householding tasks. The MSF4J hides all the complexities of creating a web service and provide a decent API to develop microservices in minutes. Let's dirt your hands with microservices: