last modified January 10, 2023
RESTEasy CRUD tutorial shows how to create a JAX-RS CRUD example with RESTEasy.
RESTEasy is a Java framework for developing RESTful Web Services. It is a fully certified and portable implementation of the JAX-RS 2.0 specification. JAX-RS 2.0 specification is a JCP (Java Community Process) specification that provides a Java API for RESTful Web Services over the HTTP protocol.
RESTEasy can run in any Servlet container.
JAX-RS has annotations for responding to HTTP requests.
The following example is a simple RESTful CRUD application. Create, Read, Update, and Delete (CRUD) are the four basic functions of persistent storage.
The data is loaded at the start of the application in a web listener.
There are two scripts: the schema.sql creates the
table and the data.sql inserts data into the table.
$ tree . ├── nb-configuration.xml ├── pom.xml └── src ├── main │ ├── java │ │ └── com │ │ └── zetcode │ │ ├── conf │ │ │ ├── AppConfig.java │ │ │ └── MyAppInitializer.java │ │ ├── dao │ │ │ ├── CityDao.java │ │ │ └── ICityDao.java │ │ ├── model │ │ │ └── City.java │ │ ├── resource │ │ │ └── MyResource.java │ │ └── service │ │ ├── CityService.java │ │ └── ICityService.java │ ├── resources │ │ └── sql │ │ ├── data.sql │ │ └── schema.sql │ └── webapp │ ├── META-INF │ │ └── context.xml │ └── WEB-INF │ └── beans.xml └── test └── java
This is the project structure.
<?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.zetcode</groupId> <artifactId>RestEasyLoadScripts</artifactId> <version>1.0-SNAPSHOT</version> <packaging>war</packaging> <name>RestEasyLoadScripts</name> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <maven.compiler.source>11</maven.compiler.source> <maven.compiler.target>11</maven.compiler.target> </properties> <dependencies> <!-- Set up RESTEasy--> <dependency> <groupId>org.jboss.resteasy</groupId> <artifactId>resteasy-jaxrs</artifactId> <version>3.1.4.Final</version> </dependency> <dependency> <groupId>org.jboss.resteasy</groupId> <artifactId>resteasy-servlet-initializer</artifactId> <version>3.1.4.Final</version> </dependency> <dependency> <groupId>org.jboss.resteasy</groupId> <artifactId>resteasy-jackson-provider</artifactId> <version>3.1.4.Final</version> </dependency> <!-- CDI for RESTEasy--> <dependency> <groupId>org.jboss.resteasy</groupId> <artifactId>resteasy-cdi</artifactId> <version>3.1.4.Final</version> </dependency> <dependency> <groupId>org.jboss.weld.servlet</groupId> <artifactId>weld-servlet-shaded</artifactId> <version>3.0.2.Final</version> </dependency> <!-- Spring JdbcTemplate --> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-jdbc</artifactId> <version>5.0.3.RELEASE</version> </dependency> <!-- H2 driver --> <dependency> <groupId>com.h2database</groupId> <artifactId>h2</artifactId> <version>1.4.196</version> </dependency> <!-- Needed for @WebListener --> <dependency> <groupId>javax.servlet</groupId> <artifactId>javax.servlet-api</artifactId> <version>4.0.0</version> <scope>provided</scope> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-war-plugin</artifactId> <version>2.3</version> <configuration> <failOnMissingWebXml>false</failOnMissingWebXml> </configuration> </plugin> </plugins> </build> </project>
This is the Maven POM file. It contains dependencies for RESTEasy, CDI for RESTEasy, Jackson provider, H2 driver, Spring JdbcTemplate, and Java Servlets (for web listeners).
<?xml version="1.0" encoding="UTF-8"?> <Context path="/RestEasyCrud"/>
In the Tomcat's context.xml configuration file, we define
the application context path.
<?xml version="1.0"?> <beans xmlns="http://xmlns.jcp.org/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/beans_1_1.xsd" version="1.1" bean-discovery-mode="all"> </beans>
Applications that use CDI must have a beans.xml file defined. It can
be empty, like in our case. For web applications, the beans.xml file
must be in the WEB-INF directory. For EJB modules or JAR files, the
beans.xml file must be in the META-INF directory.
CREATE TABLE cities(id INT PRIMARY KEY AUTO_INCREMENT, name VARCHAR(100), population INT);
The schema.sql creates a database schema.
INSERT INTO cities(name, population) VALUES('Bratislava', 432000);
INSERT INTO cities(name, population) VALUES('Budapest', 1759000);
INSERT INTO cities(name, population) VALUES('Prague', 1280000);
INSERT INTO cities(name, population) VALUES('Warsaw', 1748000);
INSERT INTO cities(name, population) VALUES('Los Angeles', 3971000);
INSERT INTO cities(name, population) VALUES('New York', 8550000);
INSERT INTO cities(name, population) VALUES('Edinburgh', 464000);
INSERT INTO cities(name, population) VALUES('Berlin', 3671000);
The data.sql inserts data into the database table.
package com.zetcode.conf;
import javax.ws.rs.ApplicationPath;
import javax.ws.rs.core.Application;
@ApplicationPath("rest")
public class AppConfig extends Application {
}
This is the application configuration class. The Application
defines the components of a JAX-RS application and supplies additional
meta-data.
@ApplicationPath("rest")
With the @ApplicationPath annotation, we set the path to RESTful
web services.
package com.zetcode.conf;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import javax.servlet.annotation.WebListener;
import org.springframework.jdbc.datasource.SimpleDriverDataSource;
@WebListener
public class MyAppInitializer implements ServletContextListener {
@Override
public void contextInitialized(ServletContextEvent sce) {
Logger lgr = Logger.getLogger(MyAppInitializer.class.getName());
lgr.log(Level.INFO, "executing contextInitialized()");
String url = "jdbc:h2:mem:testdb;DB_CLOSE_DELAY=-1;"
+ "INIT=RUNSCRIPT FROM 'classpath:/sql/schema.sql'"
+ "\\;RUNSCRIPT FROM 'classpath:/sql/data.sql'";
SimpleDriverDataSource ds = new SimpleDriverDataSource();
ds.setDriver(new org.h2.Driver());
ds.setUrl(url);
try (Connection con = ds.getConnection()) {
} catch (SQLException ex) {
lgr.log(Level.SEVERE, ex.getMessage(), ex);
}
}
@Override
public void contextDestroyed(ServletContextEvent sce) {
}
}
The database scripts are initialized in a web listener.
@WebListener
public class MyAppInitializer implements ServletContextListener {
The @WebListener annotation is used to declare a web listener.
@Override
public void contextInitialized(ServletContextEvent sce) {
The ServletContextListener's contextInitialized method is
called when the web application initialization starts.
String url = "jdbc:h2:mem:testdb;DB_CLOSE_DELAY=-1;" + "INIT=RUNSCRIPT FROM 'classpath:/sql/schema.sql'" + "\\;RUNSCRIPT FROM 'classpath:/sql/data.sql'";
In this connection string URL, we create an in-memory database called testdb.
The DB_CLOSE_DELAY keeps the content of an in-memory database as long as
the virtual machine is alive. Otherwise, the database is deleted when the connection is
closed. The RUNSCRIPT command executes the database scripts.
SimpleDriverDataSource ds = new SimpleDriverDataSource(); ds.setDriver(new org.h2.Driver()); ds.setUrl(url);
We set up a SimpleDriverDataSource. It is a simple data source that
does not support connection pooling. It creates a new connection for each call.
try (Connection con = ds.getConnection()) {
} catch (SQLException ex) {
lgr.log(Level.SEVERE, ex.getMessage(), ex);
}
The database scripts are executed when the connection is created.
package com.zetcode.model;
import java.util.Objects;
public class City {
private Long id;
private String name;
private int population;
public City() {
}
public City(String name, int population) {
this.name = name;
this.population = population;
}
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getPopulation() {
return population;
}
public void setPopulation(int population) {
this.population = population;
}
@Override
public int hashCode() {
int hash = 3;
hash = 71 * hash + Objects.hashCode(this.id);
hash = 71 * hash + Objects.hashCode(this.name);
hash = 71 * hash + this.population;
return hash;
}
@Override
public boolean equals(Object obj) {
if (this == obj) {
return true;
}
if (obj == null) {
return false;
}
if (getClass() != obj.getClass()) {
return false;
}
final City other = (City) obj;
if (this.population != other.population) {
return false;
}
if (!Objects.equals(this.name, other.name)) {
return false;
}
return Objects.equals(this.id, other.id);
}
@Override
public String toString() {
StringBuilder builder = new StringBuilder();
builder.append("City{id=").append(id).append(", name=")
.append(name).append(", population=")
.append(population).append("}");
return builder.toString();
}
}
This is a City model class. It contains three attributes:
id, name, and population.
package com.zetcode.service;
import com.zetcode.model.City;
import java.util.List;
public interface ICityService {
public List<City> findAll();
public boolean save(City city);
public City find(Long id);
public boolean update(City city, Long id);
public boolean delete(Long id);
}
ICityService contains the CRUD contract methods. We have
methods for finding cities, saving a city, updating a city, and deleting
a city.
package com.zetcode.service;
import com.zetcode.dao.ICityDao;
import com.zetcode.model.City;
import java.util.List;
import javax.inject.Inject;
public class CityService implements ICityService {
@Inject
private ICityDao cityDao;
@Override
public List<City> findAll() {
return cityDao.findAll();
}
@Override
public boolean save(City city) {
return cityDao.save(city);
}
@Override
public City find(Long id) {
return cityDao.find(id);
}
@Override
public boolean update(City city, Long id) {
return cityDao.update(city, id);
}
@Override
public boolean delete(Long id) {
return cityDao.delete(id);
}
}
CityService contains the implementation for the service
methods. It delegates the actual job to the CityDao.
package com.zetcode.dao;
import com.zetcode.model.City;
import java.util.List;
public interface ICityDao {
public List<City> findAll();
public boolean save(City city);
public City find(Long id);
public boolean update(City city, Long id);
public boolean delete(Long id);
}
The ICityDao contains the contract methods.
package com.zetcode.dao;
import com.zetcode.conf.AppConfig;
import com.zetcode.model.City;
import java.util.ArrayList;
import java.util.List;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.springframework.dao.DataAccessException;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.datasource.SimpleDriverDataSource;
public class CityDao implements ICityDao {
@Override
public List<City> findAll() {
SimpleDriverDataSource ds = new SimpleDriverDataSource();
ds.setDriver(new org.h2.Driver());
ds.setUrl("jdbc:h2:mem:testdb");
List<City> cities = new ArrayList<>();
String query = "SELECT * FROM cities;";
try {
JdbcTemplate jtm = new JdbcTemplate(ds);
cities = jtm.query(query,
new BeanPropertyRowMapper(City.class));
} catch (DataAccessException dae) {
Logger lgr = Logger.getLogger(CityDao.class.getName());
lgr.log(Level.SEVERE, dae.getMessage(), dae);
}
return cities;
}
@Override
public boolean save(City city) {
SimpleDriverDataSource ds = new SimpleDriverDataSource();
ds.setDriver(new org.h2.Driver());
ds.setUrl("jdbc:h2:mem:testdb");
String sql = "INSERT INTO cities(name, population) VALUES (?, ?)";
boolean ret = true;
try {
JdbcTemplate jtm = new JdbcTemplate(ds);
jtm.update(sql, new Object[]{city.getName(),
city.getPopulation()});
} catch (DataAccessException dae) {
Logger lgr = Logger.getLogger(CityDao.class.getName());
lgr.log(Level.SEVERE, dae.getMessage(), dae);
ret = false;
}
return ret;
}
@Override
public City find(Long id) {
SimpleDriverDataSource ds = new SimpleDriverDataSource();
ds.setDriver(new org.h2.Driver());
ds.setUrl("jdbc:h2:mem:testdb");
String sql = "SELECT * FROM cities WHERE Id=?";
City city = new City();
try {
JdbcTemplate jtm = new JdbcTemplate(ds);
city = (City) jtm.queryForObject(sql, new Object[]{id},
new BeanPropertyRowMapper(City.class));
} catch (DataAccessException dae) {
Logger lgr = Logger.getLogger(CityDao.class.getName());
lgr.log(Level.SEVERE, dae.getMessage(), dae);
}
return city;
}
@Override
public boolean update(City city, Long id) {
SimpleDriverDataSource ds = new SimpleDriverDataSource();
ds.setDriver(new org.h2.Driver());
ds.setUrl("jdbc:h2:mem:testdb");
boolean ret = true;
String sql = "UPDATE cities SET name=?, population=? WHERE Id=?";
try {
JdbcTemplate jtm = new JdbcTemplate(ds);
int nOfRows = jtm.update(sql, new Object[]{city.getName(),
city.getPopulation(), id});
if (nOfRows != 1) {
ret = false;
}
} catch (DataAccessException dae) {
Logger lgr = Logger.getLogger(CityDao.class.getName());
lgr.log(Level.SEVERE, dae.getMessage(), dae);
ret = false;
}
return ret;
}
@Override
public boolean delete(Long id) {
SimpleDriverDataSource ds = new SimpleDriverDataSource();
ds.setDriver(new org.h2.Driver());
ds.setUrl("jdbc:h2:mem:testdb");
boolean ret = true;
String sql = "DELETE FROM cities WHERE Id=?";
try {
JdbcTemplate jtm = new JdbcTemplate(ds);
int nOfRows = jtm.update(sql, new Object[]{id});
if (nOfRows != 1) {
ret = false;
}
} catch (DataAccessException dae) {
Logger lgr = Logger.getLogger(CityDao.class.getName());
lgr.log(Level.SEVERE, dae.getMessage(), dae);
ret = false;
}
return ret;
}
}
CityDao cointains the implementation of the ICityDao methods.
SimpleDriverDataSource ds = new SimpleDriverDataSource();
ds.setDriver(new org.h2.Driver());
ds.setUrl("jdbc:h2:mem:testdb");
SimpleDriverDataSource is used to build a data source
for the in-memory H2 database.
JdbcTemplate jtm = new JdbcTemplate(ds); cities = jtm.query(query, new BeanPropertyRowMapper(City.class));
Spring's JdbcTemplate is used to execute queries and
other JDBC statements.
} catch (DataAccessException dae) {
Logger lgr = Logger.getLogger(CityDao.class.getName());
lgr.log(Level.SEVERE, dae.getMessage(), dae);
}
Spring's DataAccessException is thrown for all kinds of
JDBC exceptions
@Override
public boolean save(City city) {
The save method, as well as the update
and delete methods, return a boolean value indicating
whether the task completed OK. This is used for determining the
status code of the response.
package com.zetcode.resource;
import com.zetcode.model.City;
import com.zetcode.service.ICityService;
import java.util.List;
import javax.inject.Inject;
import javax.ws.rs.Consumes;
import javax.ws.rs.DELETE;
import javax.ws.rs.FormParam;
import javax.ws.rs.GET;
import javax.ws.rs.POST;
import javax.ws.rs.PUT;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Response;
@Path("cities")
public class MyResource {
@Inject
private ICityService cityService;
@GET
@Produces(MediaType.APPLICATION_JSON)
public Response getCities() {
List<City> cities = cityService.findAll();
if (!cities.isEmpty()) {
return Response.ok(cities).build();
} else {
return Response.status(Response.Status.NOT_FOUND).build();
}
}
@Path("/{id}")
@GET
@Produces(MediaType.APPLICATION_JSON)
public Response findCity(@PathParam("id") Long id) {
City city = cityService.find(id);
if (city.getId() != null) {
return Response.ok(city).build();
} else {
return Response.status(Response.Status.NOT_FOUND).build();
}
}
@POST
@Consumes(MediaType.APPLICATION_FORM_URLENCODED)
public Response saveCity(@FormParam("name") String name,
@FormParam("population") int population) {
City city = new City();
city.setName(name);
city.setPopulation(population);
boolean r = cityService.save(city);
if (r) {
return Response.ok().status(Response.Status.CREATED).build();
} else {
return Response.notModified().build();
}
}
@Path("/{id}")
@PUT
@Consumes(MediaType.APPLICATION_FORM_URLENCODED)
public Response updateCity(@FormParam("name") String name,
@FormParam("population") int population,
@PathParam("id") Long id) {
City city = new City();
city.setName(name);
city.setPopulation(population);
boolean r = cityService.update(city, id);
if (r) {
return Response.ok().status(Response.Status.NO_CONTENT).build();
} else {
return Response.notModified().build();
}
}
@Path("/{id}")
@DELETE
@Produces(MediaType.APPLICATION_JSON)
public Response deleteCity(@PathParam("id") Long id) {
boolean r = cityService.delete(id);
if (r) {
return Response.ok().status(Response.Status.NO_CONTENT).build();
} else {
return Response.notModified().build();
}
}
}
This is the MyResource class.
@Path("cities")
public class MyResource {
The @Path specifies the URL to which the resource responds.
@Inject private ICityService cityService;
With the @Inject annotation, we inject the city service object
into the cityService field.
@GET
@Produces(MediaType.APPLICATION_JSON)
public Response getCities() {
The @GET annotation indicates that the annotated method
responds to HTTP GET requests. With the @Produces annotation,
we define that the method produces JSON.
List<City> cities = cityService.findAll();
if (!cities.isEmpty()) {
return Response.ok(cities).build();
} else {
return Response.status(Response.Status.NOT_FOUND).build();
}
We call the findAll service method and return
a list of all cities. On success, we return data with
Response.ok(cities).build If the service method does not
find any data, we return Response.Status.NOT_FOUND.
@Path("/{id}")
@GET
@Produces(MediaType.APPLICATION_JSON)
public Response findCity(@PathParam("id") Long id) {
For finding a particular city by its Id, we have a path parameter
with @Path("/{id}"). The id is retrieved with
@PathParam("id") annotation.
@POST
@Consumes(MediaType.APPLICATION_FORM_URLENCODED)
public Response saveCity(@FormParam("name") String name,
@FormParam("population") int population) {
When creating a new resource, we use the @POST annotation.
With the @Consumes(MediaType.APPLICATION_FORM_URLENCODED) we
set that the saveCity receives enconded data from the body
of the request. The data from the body request is retrieved with
the @FormParam annotation.
return Response.ok().status(Response.Status.CREATED).build();
For a newly created resource, we send back Response.Status.CREATED.
@Path("/{id}")
@PUT
@Consumes(MediaType.APPLICATION_FORM_URLENCODED)
public Response updateCity(@FormParam("name") String name,
@FormParam("population") int population,
@PathParam("id") Long id) {
To modify a resource, we use the @PUT annotation. The Id
of the resource is retrieved from the path, the modified data from
the body of the request.
@Path("/{id}")
@DELETE
@Produces(MediaType.APPLICATION_JSON)
public Response deleteCity(@PathParam("id") Long id) {
To delete a resource, we use the @DELETE annotation.
return Response.ok().status(Response.Status.NO_CONTENT).build();
The Response.Status.NO_CONTENT can be used for resource
updating and deletion.
$ curl localhost:8084/RestEasyCrud/rest/cities/ -i
HTTP/1.1 200 OK
Server: Apache-Coyote/1.1
Content-Type: application/json
Content-Length: 383
Date: 2018年2月19日 12:19:24 GMT
[{"id":1,"name":"Bratislava","population":432000},
{"id":2,"name":"Budapest","population":1759000},
{"id":3,"name":"Prague","population":1280000},
{"id":4,"name":"Warsaw","population":1748000},
{"id":5,"name":"Los Angeles","population":3971000},
{"id":6,"name":"New York","population":8550000},
{"id":7,"name":"Edinburgh","population":464000},
{"id":8,"name":"Berlin","population":3671000}]
We get all the cities with a GET request.
$ curl -X POST -d name=Kiev -d population=2877000 localhost:8084/RestEasyCrud/rest/cities/ -i HTTP/1.1 201 Created Server: Apache-Coyote/1.1 Content-Length: 0 Date: 2018年2月19日 12:21:25 GMT
We create a new city resource with a POST request.
$ curl -X DELETE localhost:8084/RestEasyCrud/rest/cities/1 -i HTTP/1.1 204 No Content Server: Apache-Coyote/1.1 Date: 2018年2月19日 12:23:20 GMT
We delete a resource with a DELETE request.
$ curl localhost:8084/RestEasyCrud/rest/cities/ -i HTTP/1.1 200 OK Server: Apache-Coyote/1.1 Content-Type: application/json Content-Length: 428 Date: 2018年2月19日 12:24:42 GMT
We modify a resource with a PUT request.
In this tutorial, we have created a CRUD RESTFul application with RESTEasy and H2 database. We used Spring's JdbcTemplate to connect to H2. The application was deployed on Tomcat.