RESTful Java Play Framework

Simple JPA CRUD

Prerequisite

Play Framework 2.4.xDownload here

Setup the play framework (installing)JDK 1.8 (or later)IntelliJ CE

Create New Project

Through Command Line type: activator new

Create New Project

Open IntelliJ and import the new project

Create New Project

choose import project from external: SBT

And next just let the default value, click

finish

Create New Project

Here is the structure of Play

framework

The Objective

Create RESTful with Java Play FrameworkBuild basic API: GET, POST, PUT, DELETEBuild parameterize API

Use ORM (Object Relational Mapping) : JPA (Java Persistence Api)

Configuration

build.sbt (root)name := """Java-Play-RESTful-JPA"""

version := "1.0-SNAPSHOT"

lazy val root = (project in file(".")).enablePlugins(PlayJava)

scalaVersion := "2.11.6"

libraryDependencies ++= Seq( javaJdbc, cache, javaWs, javaJpa, "org.hibernate" % "hibernate-entitymanager" % "3.6.9.Final”)

routesGenerator := InjectedRoutesGenerator

Configuration

conf/application.conf, add:db.default.driver=org.h2.Driverdb.default.url="jdbc:h2:mem:play"db.default.jndiName=DefaultDSjpa.default=defaultPersistenceUnit

For simple purpose (development), we use mem as database on memory.

Configuration

Create persistence.xml at conf/META-INF

<persistence xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd" version="2.0">

<persistence-unit name="defaultPersistenceUnit" transaction-type="RESOURCE_LOCAL"> <provider>org.hibernate.ejb.HibernatePersistence</provider> <non-jta-data-source>DefaultDS</non-jta-data-source> <properties> <property name="hibernate.dialect" value="org.hibernate.dialect.H2Dialect"/>

<property name="hibernate.hbm2ddl.auto" value="update"/> </properties> </persistence-unit>

</persistence>

Create Simple POST

At conf/routes, we add url for API access.

POST /person controllers.Application.addperson()

The method is POST, the access to this API is {baseurl}/person. For this example, we use json format for body.The process is on controllers/Application.java method addperson()

Create models

Create models/Person.java

package models;

import javax.persistence.Entity;import javax.persistence.GeneratedValue;import javax.persistence.Id;

@Entitypublic class Person {

@Id @GeneratedValue public long id;

public String name;}

Create controller

Add the method addPerson() at controller application.java@Transactional@BodyParser.Of(BodyParser.Json.class)public Result addPerson(){ JsonNode json = request().body().asJson();

Person person = Json.fromJson(json, Person.class);

if (person.toString().equals("")){ return badRequest("Missing parameter"); }

JPA.em().persist(person); return ok();}

Let’s try

First create run configuration: Choose SBT Task and chose for the Task is run.Execute Run.Let curl from command line:curl -X POST -H "Content-Type: application/json" -H "Cache-Control: no-cache" -d '{ "name":"Faren"}' 'http://localhost:9000/person'

It will store one object Person.

Create Simple GET

Add url on routesGET /person controllers.Application.listPerson()

Add controller Application.java@Transactional(readOnly = true)public Result listPerson(){ CriteriaBuilder cb = JPA.em().getCriteriaBuilder(); CriteriaQuery<Person> cq = cb.createQuery(Person.class);

Root<Person> root = cq.from(Person.class); CriteriaQuery<Person> all = cq.select(root);

TypedQuery<Person> allQuery = JPA.em().createQuery(all);

JsonNode jsonNode = toJson(allQuery.getResultList()); return ok(jsonNode);}

Let’s try

No need to Rerun the server. Just curl the GET method from command line.curl -X GET -H "Cache-Control: no-cache" 'http://localhost:9000/person’

The Output:[{"id":1,"name":"Faren"},{"id":2,"name":"Dromdev"},{"id":3,"name":"inideveloper"}]

Get single record

Add url on routesGET /person/:id controllers.Application.getPerson(id: Long)

Add controller Application.java@Transactionalpublic Result getPerson(Long id){ Person person = JPA.em().find(Person.class, id);

if (person==null){ return notFound("User not found"); }

return ok(toJson(person));}

Let’s try

Run curl on command line:curl -X GET -H "Cache-Control: no-cache" 'http://localhost:9000/person/1’

The Output:{ "id": 1, "name": "Faren"}

PUTAdd url on routesPUT /person/:id controllers.Application.updatePerson(id: Long)

Add controller Application.java@Transactionalpublic Result updatePerson(Long id){ Person person = JPA.em().find(Person.class, id);

if (person==null){ return notFound("User not found"); }

JsonNode json= request().body().asJson();

Person personToBe = Json.fromJson(json, Person.class);

person.name = personToBe.name;

return ok();}

DELETE

Add url on routesDELETE /person/:id controllers.Application.deletePerson(id: Long)

Add controller Application.java@Transactionalpublic Result deletePerson(Long id){ Person person = JPA.em().find(Person.class, id);

if (person==null){ return notFound("User not found"); }

JPA.em().remove(person);

return ok();}

API with parameterFor example:http://localhost:9000/searchperson?name=inideveloper

Add url on routesGET /searchperson controllers.Application.searchPerson(name: String)

Add controller Application.java@Transactionalpublic Result searchPerson(String name){

TypedQuery<Person> query = JPA.em().createQuery ("select p from Person p where p.name = :name", Person.class) .setParameter("name", name);

try { Person person = query.getSingleResult(); return ok(toJson(person));

}catch (NoResultException e){ return notFound("User not found"); }

}

Full Source Code:

https://github.com/faren/java-play-jpa