How to autowire RestTemplate using annotations

Question

When I try to autowire Spring RestTemplate, I am getting following error:

nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [org.springframework.web.client.RestTemplate] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency.

Using Spring 4 in an annotation driven environment.

My dispatcher servlet is configured as follows:

<context:component-scan base-package="in.myproject" />
<mvc:default-servlet-handler />    
<mvc:annotation-driven />
<bean id="restTemplate" class="org.springframework.web.client.RestTemplate"/>

My class in which I am trying to autowire RestTemplate is as follows:

@Service("httpService")
public class HttpServiceImpl implements HttpService {

@Autowired
private RestTemplate restTemplate;

@Override
public void sendUserId(String userId){

    MultiValueMap<String, String> map = new LinkedMultiValueMap<>();
    map.add("userId", userId);
    map.add("secretKey", "kbhyutu7576465duyfy");

    restTemplate.postForObject("http://localhost:8081/api/user", map, null);


    }
}

Answer 1

Errors you'll see if a RestTemplate isn't defined

Consider defining a bean of type 'org.springframework.web.client.RestTemplate' in your configuration.

or

No qualifying bean of type [org.springframework.web.client.RestTemplate] found

How to define a RestTemplate via annotations

Depending on which technologies you're using and what versions will influence how you define a RestTemplate in your @Configuration class.

Spring >= 4 without Spring Boot

Simply define an @Bean:

@Bean
public RestTemplate restTemplate() {
    return new RestTemplate();
}

Spring Boot <= 1.3

No need to define one, Spring Boot automatically defines one for you.

Spring Boot >= 1.4

Spring Boot no longer automatically defines a RestTemplate but instead defines a RestTemplateBuilder allowing you more control over the RestTemplate that gets created. You can inject the RestTemplateBuilder as an argument in your @Bean method to create a RestTemplate:

@Bean
public RestTemplate restTemplate(RestTemplateBuilder builder) {
   // Do any additional configuration here
   return builder.build();
}

Using it in your class

@Autowired
private RestTemplate restTemplate;

or

@Inject
private RestTemplate restTemplate;