Could not autowire field:RestTemplate in Spring boot application

Question

I am getting below exception while running Spring Boot application during start up:

org.springframework.beans.factory.BeanCreationException: 
Error creating bean with name 'testController': 
Injection of autowired dependencies failed; 
nested exception is
org.springframework.beans.factory.BeanCreationException: 
Could not autowire field: 
private org.springframework.web.client.RestTemplate 
com.micro.test.controller.TestController.restTemplate; 
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. 
Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}

I am autowiring RestTemplate in my TestController. I am using Maven for dependency management.

TestMicroServiceApplication.java

package com.micro.test;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class TestMicroServiceApplication {

    public static void main(String[] args) {
        SpringApplication.run(TestMicroServiceApplication.class, args);
    }
}

TestController.java

package com.micro.test.controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.MediaType;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

@RestController
public class TestController {
    
    @Autowired
    private RestTemplate restTemplate;
        
    @RequestMapping(value="/micro/order/{id}",
                    method=RequestMethod.GET,
                    produces=MediaType.ALL_VALUE)
    public String placeOrder(@PathVariable("id") int customerId){
        
        System.out.println("Hit ===> PlaceOrder");

        Object[] customerJson = restTemplate.getForObject("http://localhost:8080/micro/customers", Object[].class);
        
        System.out.println(customerJson.toString());
        
        return "false";
    }

}

POM.xml

    <?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.micro.test</groupId>
    <artifactId>Test-MicroService</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>Test-MicroService</name>
    <description>Demo project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.3.3.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>
    
    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
    

</project>

Answer 1

It's exactly what the error says. You didn't create any RestTemplate bean, so it can't autowire any. If you need a RestTemplate you'll have to provide one. For example, add the following to TestMicroServiceApplication.java:

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

Since Spring boot 1.4, there's also a convenient builder that you can autowire and use to create a RestTemplate bean. The benefit is that you can use the builder pattern to register interceptors, customizers, ... .

@Bean
public RestTemplate restTemplate(RestTemplateBuilder builder) {
    return builder.build();
}

Note, in earlier versions of the Spring cloud starter for Eureka, a RestTemplate bean was created for you, but this is no longer true.