This post shows how you can add JSON support to your applications using Spring Roo. The information in this post has been taken from Spring Roo 1.1 Cookbook.
Step 1: Download Roo scripts and sample code from the following location:http://code.google.com/p/spring-roo-cookbook/downloads/list#columnprefs
Step 2: Execute the ch04_web-app.roo script that creates the flight-app Roo project, sets up
Hibernate as the persistence provider, configures MySQL as the database for the application,
creates the Flight and FlightDescription JPA entities, and defines a many-to-one
relationship between the Flight and FlightDescription entities. If you are using a
different database than MySQL or your connection settings are different than what is specified
in the script, then modify the script accordingly.
Step 3: Execute the controller all command to create controllers and JSPX views corresponding
to JPA entities in the flight-app project, as shown here:
.. roo> controller all --package ~.web
Execute the perform eclipse command to update the project's classpath settings, as
shown here:
.. roo> perform eclipse
Now, import the flight-app project into your Eclipse IDE.
Step 4: To add the json support execute the json add command against the Flight JPA entity:
~.domain.Flight roo> json add --class ~.domain.Flight
Updated SRC_MAIN_JAVA\...\domain\Flight.java
Created SRC_MAIN_JAVA\...\domain\Flight_Roo_Json.aj
Created SRC_MAIN_JAVA\...\web\FlightController_Roo_Controller_Json.aj
Executing the json add command creates
a *_Roo_Json.aj AspectJ ITD, which defines methods for converting objects of the class to
JSON documents and vice versa, as shown here:
import flexjson.JSONDeserializer;
import flexjson.JSONSerializer;
privileged aspect Flight_Roo_Json {
public String Flight.toJson() {
return new JSONSerializer().exclude("*.class").serialize(this);
}
public static Flight Flight.fromJsonToFlight(String json) {
return new JSONDeserializer().use(null, Flight.class).deserialize(json);
}
public static String Flight.toJsonArray(
Collection collection) {
...
}
public static Collection
Flight.fromJsonArrayToFlights(String json) {
...
}
}
The following code shows the FlightController_Roo_Controller_Json.aj ITD, which
was generated:
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.ResponseBody;
privileged aspect FlightController_Roo_Controller_Json {
@RequestMapping(value = "/{flightId}", method = RequestMethod.GET,
headers = "Accept=application/json")
@ResponseBody
public Object FlightController.showJson(@PathVariable("flightId") Long flightId) {
Flight flight = Flight.findFlight(flightId);
if (flight == null) {
HttpHeaders headers= new HttpHeaders();
headers.add("Content-Type", "application/text");
return new ResponseEntity(headers, HttpStatus.NOT_FOUND);
}
return flight.toJson();
}
...
}
