《一起学 Spring 之 RestTemplate 使用指南 》 一文的演示 Demo
http://blog.didispace.com/spring-boot-learning-21-1-1
https://start.spring.io "Spring Initializr"
https://www.baeldung.com/rest-template
https://www.baeldung.com/spring-rest-template-multipart-upload
https://howtodoinjava.com/spring-boot2/resttemplate-timeout-example/ "resttemplate-timeout-example"
https://howtodoinjava.com/spring-restful/resttemplate-httpclient-java-config/ "resttemplate-httpclient-java-config"
https://netty.io/ "Netty"
https://square.github.io/okhttp "OkHttp"
https://docs.spring.io/spring-framework/docs/current/javadoc-api/org/springframework/web/client/RestTemplate.html "resttemplate javadoc"
https://docs.spring.io/spring/docs/5.1.6.RELEASE/spring-framework-reference/integration.html#rest-client-access "rest-client-access"
https://docs.spring.io/spring-framework/docs/current/javadoc-api/org/springframework/web/client/RestOperations.html "restoperation javadoc"