Spring RestTemplate provides a convenient way to test RESTful web services.
spring-web
, introduced in Spring 3.Let’s look at Spring RestTemplate example where we will test REST web services created in Spring Data JPA article. Below table illustrates the URIs supported by this rest web service. .tg {border-collapse:collapse;border-spacing:0;border-color:#999;} .tg td{font-family:Arial, sans-serif;font-size:14px;padding:10px 5px;border-style:solid;border-width:1px;overflow:hidden;word-break:normal;border-color:#999;color:#444;background-color:#F7FDFA;} .tg th{font-family:Arial, sans-serif;font-size:14px;font-weight:normal;padding:10px 5px;border-style:solid;border-width:1px;overflow:hidden;word-break:normal;border-color:#999;color:#fff;background-color:#26ADE4;} .tg .tg-baqh{text-align:center;vertical-align:top} .tg .tg-yw4l{vertical-align:top}
URI | HTTP Method | Description |
---|---|---|
/springData/person | GET | Get all persons from database |
/springData/person/{id} | GET | Get person by id |
/springData/person | POST | Add person to database |
/springData/person | PUT | Update person |
/springData/person/{id} | DELETE | Delete person by id |
Let’s start creating our Rest client project to test these web services. Below image shows our final Spring RestTemplate example project.
We need spring-core
, spring-context
dependencies for spring framework. Then we need spring-web
artefact that contains RestTemplate
class. We also need jackson-mapper-asl
for Spring JSON support through Jackson API.
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="https://maven.apache.org/POM/4.0.0" xmlns:xsi="https://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="https://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.journaldev.spring</groupId>
<artifactId>SpringRestTemplate</artifactId>
<version>1.0-SNAPSHOT</version>
<properties>
<spring.framework>4.3.0.RELEASE</spring.framework>
<spring.web>3.0.2.RELEASE</spring.web>
<serializer.version>2.8.1</serializer.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-core</artifactId>
<version>${spring.framework}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>${spring.framework}</version>
</dependency>
<dependency>
<groupId>org.codehaus.jackson</groupId>
<artifactId>jackson-mapper-asl</artifactId>
<version>1.9.4</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-web</artifactId>
<version>${spring.web}</version>
</dependency>
</dependencies>
</project>
We have to define a spring bean for RestTemplate class, that’s done in AppConfig
class.
package com.journaldev.spring.config;
import org.codehaus.jackson.map.ObjectMapper;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.converter.json.MappingJacksonHttpMessageConverter;
import org.springframework.web.client.RestTemplate;
@Configuration
@ComponentScan("com.journaldev.spring")
public class AppConfig {
@Bean
RestTemplate restTemplate() {
RestTemplate restTemplate = new RestTemplate();
MappingJacksonHttpMessageConverter converter = new MappingJacksonHttpMessageConverter();
converter.setObjectMapper(new ObjectMapper());
restTemplate.getMessageConverters().add(converter);
return restTemplate;
}
}
Note that RestTamplate uses MessageConverter and we need to set this property in the RestTemplate bean. In our example we are using MappingJacksonHttpMessageConverter
for fetching data from JSON format.
Since we are trying to convert JSON returned by our web service to a java object using jackson mapper, we have to create the model class for this. Note that this model class will be very similar to the model class used in the web service, except that here we don’t need JPA annotations.
package com.journaldev.spring.model;
public class Person {
private Long id;
private Integer age;
private String firstName;
private String lastName;
public Person() {
}
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
public String getFirstName() {
return firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
public String getLastName() {
return lastName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
@Override
public String toString() {
return "Person{" + "id=" + id + ", age=" + age + ", firstName='" + firstName + '\'' + ", lastName='" + lastName
+ '\'' + '}';
}
}
Final step is to create the client classes that will use RestTemplate bean defined above.
package com.journaldev.spring.config;
import java.util.List;
import org.springframework.http.HttpStatus;
import com.journaldev.spring.model.Person;
public interface PersonClient {
List<Person> getAllPerson();
Person getById(Long id);
HttpStatus addPerson(Person person);
void updatePerson(Person person);
void deletePerson(Long id);
}
package com.journaldev.spring.config;
import java.util.Arrays;
import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Service;
import org.springframework.web.client.RestTemplate;
import com.journaldev.spring.model.Person;
@Service
public class PersonClientImpl implements PersonClient {
@Autowired
RestTemplate restTemplate;
final String ROOT_URI = "https://localhost:8080/springData/person";
public List<Person> getAllPerson() {
ResponseEntity<Person[]> response = restTemplate.getForEntity(ROOT_URI, Person[].class);
return Arrays.asList(response.getBody());
}
public Person getById(Long id) {
ResponseEntity<Person> response = restTemplate.getForEntity(ROOT_URI + "/"+id, Person.class);
return response.getBody();
}
public HttpStatus addPerson(Person person) {
ResponseEntity<HttpStatus> response = restTemplate.postForEntity(ROOT_URI, person, HttpStatus.class);
return response.getBody();
}
public void updatePerson(Person person) {
restTemplate.put(ROOT_URI, person);
}
public void deletePerson(Long id) {
restTemplate.delete(ROOT_URI + id);
}
}
The code is self understood, we are calling RestTemplate methods based on the URI and the HTTP method and by passing appropriate request object if needed.
It’s time to test our Spring RestTemplate example project, below class shows how to use RestTemplate methods in Spring way.
package com.journaldev.spring;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.http.HttpStatus;
import com.journaldev.spring.config.AppConfig;
import com.journaldev.spring.config.PersonClient;
import com.journaldev.spring.model.Person;
public class Main {
public static void main(String[] args) {
AnnotationConfigApplicationContext applicationContext = new AnnotationConfigApplicationContext(AppConfig.class);
PersonClient client = applicationContext.getBean(PersonClient.class);
System.out.println("Getting list of all people:");
for (Person p : client.getAllPerson()) {
System.out.println(p);
}
System.out.println("\nGetting person with ID 2");
Person personById = client.getById(2L);
System.out.println(personById);
System.out.println("Adding a Person");
Person p = new Person();
p.setAge(50);
p.setFirstName("David");
p.setLastName("Blain");
HttpStatus status = client.addPerson(p);
System.out.println("Add Person Response = " + status);
applicationContext.close();
}
}
When I run above program against my local setup, I get following output.
Getting list of all people:
Person{id=2, age=30, firstName='Oksi', lastName=' Bahatskaya'}
Person{id=1, age=30, firstName='Vlad', lastName='Mateo'}
Getting person with ID 2
Person{id=2, age=30, firstName='Oksi', lastName=' Bahatskaya'}
Adding a Person
Add Person Response = 201
Below image shows the web service database table data before and after executing above program. As you can see that the program output matches with the sample table data. That’s all for Spring RestTemplate example, you can download the project from below link.
Download Spring RestTemplate Example Project
Reference: API Doc
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Hi pankaj, I need urgent help on as how can we consume existing SOAP service method calls using REST form Request you to please help me or you can share a link for getting to know how Also please let me know how to consume SOAP web service using RestTemplate Thanks, Shreedhar Bhumralkar
- Shreedhar Bhumralkar
Thanks for explanation. Can you suggest best way to make 100-1000 post request to any rest URL. I am worried about connection establishment/closer for each request, although I don’t have to write code for same.
- rohit verma
How to run this app? I am getting below error: INFO: Refreshing org.springframework.context.annotation.AnnotationConfigApplicationContext@2ff4f00f: startup date [Wed Nov 14 10:40:41 IST 2018]; root of context hierarchy Getting list of all people: Exception in thread “main” org.springframework.web.client.ResourceAccessException: I/O error: Connection refused: connect; nested exception is java.net.ConnectException: Connection refused: connect at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:453) at org.springframework.web.client.RestTemplate.execute(RestTemplate.java:401) at org.springframework.web.client.RestTemplate.getForEntity(RestTemplate.java:221) at com.journaldev.spring.config.PersonClientImpl.getAllPerson(PersonClientImpl.java:23) at com.journaldev.spring.Main.main(Main.java:19) Caused by: java.net.ConnectException: Connection refused: connect at java.net.DualStackPlainSocketImpl.connect0(Native Method) at java.net.DualStackPlainSocketImpl.socketConnect(Unknown Source) at java.net.AbstractPlainSocketImpl.doConnect(Unknown Source) at java.net.AbstractPlainSocketImpl.connectToAddress(Unknown Source) at java.net.AbstractPlainSocketImpl.connect(Unknown Source)
- priyanka