Dropwizard – Tutorial to write APIs to read/write from database using hibernate

	<?xml version="1.0" encoding="UTF-8"?>
	<project xmlns="http://maven.apache.org/POM/4.0.0"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>

	<groupId>com.wordpress.nullpointerexception1</groupId>
	<artifactId>myRestProject</artifactId>
	<version>1.0-SNAPSHOT</version>

	<properties>
	<dropwizard.version>1.3.5</dropwizard.version>
	</properties>

	<dependencies>
	<dependency>
	<groupId>io.dropwizard</groupId>
	<artifactId>dropwizard-core</artifactId>
	<version>${dropwizard.version}</version>
	</dependency>
	<dependency>
	<groupId>mysql</groupId>
	<artifactId>mysql-connector-java</artifactId>
	<version>5.1.36</version>
	</dependency>
	<dependency>
	<groupId>io.dropwizard</groupId>
	<artifactId>dropwizard-hibernate</artifactId>
	<version>${dropwizard.version}</version>
	</dependency>
	</dependencies>

	</project>

	CREATE TABLE `info` (
	`name` varchar(50) NOT NULL DEFAULT '',
	`empid` varchar(50) NOT NULL DEFAULT '',
	PRIMARY KEY (`empid`)
	) ENGINE=InnoDB DEFAULT CHARSET=utf8;

	package models;

	import lombok.Data;

	import javax.persistence.*;

	/**
	* Created by harshvardhan on 10/07/18.
	*/
	@Entity
	@Table(name = "info")
	@NamedQueries({
	@NamedQuery(name = "com.wordpress.nullpointerexception1.info.findAll",
	query = "select e from Info e")
	})
	public class Info {

	@Column(name = "name")
	private String name;

	@Id
	@Column(name = "empid")
	private String empid;

	public String getName() {
	return name;
	}

	public void setName(String name) {
	this.name = name;
	}

	public String getEmpid() {
	return empid;
	}

	public void setEmpid(String empid) {
	this.empid = empid;
	}
	}

	import io.dropwizard.hibernate.AbstractDAO;
	import org.hibernate.SessionFactory;

	import java.util.List;

	/**
	* Created by harshvardhan on 10/07/18.
	*/
	public class InfoDao extends AbstractDAO<Info> {

	public InfoDao(SessionFactory factory) {
	super(factory);
	}

	public List<Info> findAll() {
	return list(namedQuery("com.wordpress.nullpointerexception1.info.findAll"));
	}
	}

	import com.fasterxml.jackson.annotation.JsonProperty;
	import io.dropwizard.Configuration;
	import io.dropwizard.db.DataSourceFactory;

	/**
	* Created by harshvardhan on 12/07/18.
	*/
	public class MyConfiguration extends Configuration {

	private String url;

	private DataSourceFactory database = new DataSourceFactory();

	public String getUrl() {
	return url;
	}

	public void setUrl(String url) {
	this.url = url;
	}

	@JsonProperty("database")
	public DataSourceFactory getDataSourceFactory() {
	return database;
	}

	}

Add dependency to your pom.xml

	url: https://nullpointerexception1.wordpress.com/
	database:
	# the name of the JDBC driver, mysql in our case
	driverClass: com.mysql.jdbc.Driver
	# the username
	user: root
	#user: root
	# the password
	password: welcome
	#password:
	# the JDBC URL; the database is called DWGettingStarted
	url: jdbc:mysql://localhost:3306/<YOUR_DB_NAME>
	properties:
	charSet: UTF-8

	import com.codahale.metrics.annotation.Timed;
	import io.dropwizard.hibernate.UnitOfWork;

	import javax.ws.rs.GET;
	import javax.ws.rs.POST;
	import javax.ws.rs.Path;
	import java.util.List;

	/**
	* Created by harshvardhan on 12/07/18.
	*/
	@Path("/resource")
	@Produces(MediaType.APPLICATION_JSON)
	public class MyResource {

	private InfoDao infoDao;

	public MyResource(InfoDao infoDao) {
	this.infoDao = infoDao;
	}

	@GET
	@Timed
	@Path("/getName")
	public String getName() {
	return "Harsh";
	}

	@POST
	@Timed
	@Path("/postName")
	public String postName(String name) {
	System.out.println("Name given by : "+name);
	return "Ok";
	}

	@GET
	@Timed
	@UnitOfWork
	@Path("/findAllEmp")
	public List<Info> findAllEmp() {
	System.out.println("All Emp : "+infoDao.findAll());
	return infoDao.findAll();
	}
	}

	import io.dropwizard.Application;
	import io.dropwizard.db.DataSourceFactory;
	import io.dropwizard.hibernate.HibernateBundle;
	import io.dropwizard.setup.Bootstrap;
	import io.dropwizard.setup.Environment;

	/**
	* Created by harshvardhan on 12/07/18.
	*/
	public class MyApplication extends Application<MyConfiguration> {

	public static void main(String[] args) throws Exception {
	new MyApplication().run(args);
	}

	public void run(MyConfiguration myConfiguration, Environment environment) throws Exception {
	System.out.println("Value from dev.yml is "+myConfiguration.getDataSourceFactory().getUser());
	InfoDao infoDao = new InfoDao(hibernate.getSessionFactory());
	final MyResource resource = new MyResource(infoDao);
	environment.jersey().register(resource);

	}

	private HibernateBundle<MyConfiguration> hibernate = new HibernateBundle<MyConfiguration>(Info.class) {
	@Override
	public DataSourceFactory getDataSourceFactory(MyConfiguration configuration) {
	return configuration.getDataSourceFactory();
	}
	};

	@Override
	public String getName() {
	return "dropwizard-hibernate";
	}

	@Override
	public void initialize(Bootstrap<MyConfiguration> bootstrap) {
	bootstrap.addBundle(hibernate);
	}

	}