Spring去除了RestTemplate的默认导入配置

今天写了一个Demo，发现默认创建完SpringBoot的web项目后，RestTemplate无法自动注入了，报如下异常：

Field restTemplate in org.xharvard.boot.controller.RestTempController required a bean of type 'org.springframework.web.client.RestTemplate' that could not be found.
 
The injection point has the following annotations:
	- @org.springframework.beans.factory.annotation.Autowired(required=true)

查阅资料后，发现是官方去除了，原因如下：

If you need to call remote REST services from your application, you can use the Spring Framework’s RestTemplate class. Since RestTemplate instances often need to be customized before being used, Spring Boot does not provide any single auto-configured RestTemplate bean. It does, however, auto-configure a RestTemplateBuilder, which can be used to create RestTemplate instances when needed. The auto-configured RestTemplateBuilder ensures that sensible HttpMessageConverters are applied to RestTemplate instances.

官网地址：https://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/#io.rest-client.resttemplate

 默认导入了RestTemplateBuilder，可以如下处理：

@Service
public class MyService {
 
    private final RestTemplate restTemplate;
 
    public MyService(RestTemplateBuilder restTemplateBuilder) {
        this.restTemplate = restTemplateBuilder.build();
    }
 
    public Details someRestCall(String name) {
        return this.restTemplate.getForObject("/{name}/details", Details.class, name);
    }
 
}

restTemplateBuilder.build() 返回的即是 RestTemplate。