You’ll build a service and run the run_server.sh .This will accept HTTP GET requests at:

and respond with a JSON representation of a greeting:

You can customize the greeting with an optional name parameter in the query string:

The name parameter value overrides the default value of "World" and is reflected in the response:

Now that you’ve set up the project and build system, you can create your web service.

Begin the process by thinking about service interactions.

The service will handle GET requests for /greeting, optionally with a name parameter in the query string. The GET request should return a 200 OK response with JSON in the body that represents a greeting. It should look something like this:

The id field is a unique identifier for the greeting, and content is the textual representation of the greeting.

To model the greeting representation, you create a resource representation class. Provide a plain old java object with fields, constructors, and accessors for the id and content data:

src/main/java/hello/Greeting.java

Next you create the resource controller that will serve these greetings.

In Spring’s approach to building RESTful web services, HTTP requests are handled by a controller. These components are easily identified by the @RestController annotation, and the GreetingController below handles GET requests for /greeting by returning a new instance of the Greeting class:

src/main/java/hello/GreetingController.java

This controller is concise and simple, but there’s plenty going on under the hood. Let’s break it down step by step.

The @RequestMapping annotation ensures that HTTP requests to /greeting are mapped to the greeting() method.

@RequestParam binds the value of the query string parameter name into the name parameter of the greeting() method. This query string parameter is explicitly marked as optional (required=true by default): if it is absent in the request, the defaultValue of "World" is used.

The implementation of the method body creates and returns a new Greeting object with id and content attributes based on the next value from the counter, and formats the given name by using the greeting template.

A key difference between a traditional MVC controller and the RESTful web service controller above is the way that the HTTP response body is created. Rather than relying on a view technology to perform server-side rendering of the greeting data to HTML, this RESTful web service controller simply populates and returns a Greeting object. The object data will be written directly to the HTTP response as JSON.

This code uses Spring 4’s new @RestController annotation, which marks the class as a controller where every method returns a domain object instead of a view. It’s shorthand for @Controller and @ResponseBody rolled together.

The Greeting object must be converted to JSON. Thanks to Spring’s HTTP message converter support, you don’t need to do this conversion manually. Because Jackson 2 is on the classpath, Spring’s MappingJackson2HttpMessageConverter is automatically chosen to convert the Greeting instance to JSON.

Although it is possible to package this service as a traditional WAR file for deployment to an external application server, the simpler approach demonstrated below creates a standalone application. You package everything in a single, executable JAR file, driven by a good old Java main() method. Along the way, you use Spring’s support for embedding the Tomcat servlet container as the HTTP runtime, instead of deploying to an external instance.

/src/main/java/com/arch/api/restful/boot/Application.java

Logging output is displayed. The service should be up and running within a few seconds.

Now that the service is up, visit http://localhost:8080/greeting, where you see:

Provide a name query string parameter with http://localhost:8080/greeting?name=User. Notice how the value of the content attribute changes from "Hello, World!" to "Hello User!":

This change demonstrates that the @RequestParam arrangement in GreetingController is working as expected. The name parameter has been given a default value of "World", but can always be explicitly overridden through the query string.

Notice also how the id attribute has changed from 1 to 2. This proves that you are working against the same GreetingController instance across multiple requests, and that its counter field is being incremented on each call as expected.

Congratulations! You’ve just developed a RESTful web service with Spring.

Spring Data MongoDB focuses on storing data in MongoDB. It also inherits functionality from the Spring Data Commons project, such as the ability to derive queries. Essentially, you don’t have to learn the query language of MongoDB; you can simply write a handful of methods and the queries are written for you.

To see how this works, create a repository interface that queries Customer documents.

src/main/java/com/arch/api/restful/boot/CustomerMongoRepository.java

CustomerMongoRepository extends the MongoRepository interface and plugs in the type of values and id it works with: Customer and String. Out-of-the-box, this interface comes with many operations, including standard CRUD operations (create-read-update-delete).

You can define other queries as needed by simply declaring their method signature. In this case, you add findByFirstName, which essentially seeks documents of type Customer and finds the one that matches on firstName.

You also have findByLastName to find a list of people by last name.

In a typical Java application, you write a class that implements CustomerRepository and craft the queries yourself. What makes Spring Data MongoDB so useful is the fact that you don’t have to create this implementation. Spring Data MongoDB creates it on the fly when you run the application.

You Also have GridFS template for file upload and download. Please go through the steps of GridFSIntegrationTest.java Let’s wire this up and see what it looks like!

1 .Interceptors

1. AysncCalls to Rest Services

2. ErrorHandling

3. Logging with Elapsed time Usage -http://aspects.jcabi.com/

4. JDBC Calls with multi result set handling

5. Unit Test Cases

6. Traceouts.

7. Logging is controlled through Spring Profile

8. Interceptors

9. JDBC - SQL connectors - Complex MultiResultSet usecase

10. No SQL Connector (MongoDB, Grid FS , Redis Connector)

11. Profiling and quick Perform test.

Top Annotations.

*@Async

@Cacheable

@Immutable

@LogExceptions

@Loggable

@Quietly

@Parallel

@RetryOnFailure

@ScheduleWithFixedDelay

@Timeable

@UnitedThrow*

1. JSON

2. http://docs.spring.io/spring/docs/4.3.3.RELEASE/

3. http://aspects.jcabi.com/

4. Spring Security

5. Spring Aspect

6.