A fat jar is a jar file which includes all the dependencies in one fat (uber) jar. This mode of creating a fat jar and running it in a Java process is also referred to as server-less execution.
This sample shows the use of @Produces and @Consumes annotations for bean conversions. In addition to that this demonstrates how to develop a microservice with WSO2 MSF4J, create a fat jar & run it. The sample also demonstrates generating Swagger definitions for your services using Swagger annotations.
See also; msf4j bundle
Your POM can inherit from msf4j-service. See details here.
When you need to return a bean from a resource method you can specify @Produces annotation with mime types you need to support. In this case, at runtime WSO2 MSF4J framework matches the request's Accept header with the @Produce annotation and dispatches the correct resource method. Then, when the response is sent, the returned bean will be automatically serialized to the matched mime type. See the following example.
@GET
@Path("/{symbol}")
@Produces({"application/json", "text/xml"})
public Response getQuote(@PathParam("symbol") String symbol) {
Stock stock = stockQuotes.get(symbol);
return (stock == null) ?
Response.status(Response.Status.NOT_FOUND).build() :
Response.status(Response.Status.OK).entity(stock).build();
}In the above example, if the requests Accept header is application/json, then the Stock bean object will be serialized as JSON and will be sent as the response. In the same way if the requests Accept header is text/xml, then the bean will be serialized as XML and will be sent as the respond.
If a request body is JSON or XML, then you can receive a bean for it as shown in the following example.
@POST
@Consumes("application/json")
public void addStock(Stock stock) {
stockQuotes.put(stock.getSymbol(), stock);
}In the above example, since @Consumes is set to application/json, if a JSON object that matches to the type of stock parameter is arrived in the request body, a Stock object will be automatically populated from it and passed to the resource method.
From this directory, run
mvn clean install
Use following command to run the application
java -jar target/stockquote-fatjar-*.jar
Use following cURL commands.
curl http://localhost:8080/stockquote/IBM
You should get a successful response if everything worked fine.
Use following command to run the application
java -jar -Dtransports.netty.conf=netty-transports.yml target/stockquote-fatjar-*.jar
The above command will expose the service via HTTP on port 8080 & HTTPS on 8443. Invoke the service as follows:
curl --insecure https://localhost:8443/stockquote/IBM
You should get a successful response if everything worked fine.
Swagger is a standard, language-agnostic interface to REST APIs which allows both humans and computers to discover and understand the capabilities of the service without access to source code, documentation, or through network traffic inspection.
This sample also demonstrates the usage of Swagger annotations. In order to retrieve the Swagger definition for the StockQuote microservice, go to http://localhost:8080/swagger?path=/stockquote.
This sample also demonstrates the use of JAXRS ExceptionMapper. When a request is sent to a non-existent symbol is sent, http://localhost:8080/stockquote/ZZZ for example, a SymbolNotFoundException is thrown. We have registered SymbolNotFoundMapper as the ExceptionMapper for SymbolNotFoundException and this mapper will take care of sending back an HTTP 404 with the exception message.
The following code segment shows how ExceptionMappers are registered with the MSF4J runtime.
new MicroservicesRunner().addExceptionMapper(new SymbolNotFoundMapper(), new DuplicateSymbolMapper());