If you need to call remote REST services from your application, you can use the Spring Framework’s {spring-framework-api}/web/client/RestTemplate.html[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.
The following code shows a typical example:
link:{docs-java}/features/resttemplate/MyService.java[role=include]|
Tip
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RestTemplateBuilder includes a number of useful methods that can be used to quickly configure a RestTemplate.
For example, to add BASIC auth support, you can use builder.basicAuthentication("user", "password").build().
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There are three main approaches to RestTemplate customization, depending on how broadly you want the customizations to apply.
To make the scope of any customizations as narrow as possible, inject the auto-configured RestTemplateBuilder and then call its methods as required.
Each method call returns a new RestTemplateBuilder instance, so the customizations only affect this use of the builder.
To make an application-wide, additive customization, use a RestTemplateCustomizer bean.
All such beans are automatically registered with the auto-configured RestTemplateBuilder and are applied to any templates that are built with it.
The following example shows a customizer that configures the use of a proxy for all hosts except 192.168.0.5:
link:{docs-java}/features/resttemplate/customization/MyRestTemplateCustomizer.java[role=include]Finally, you can define your own RestTemplateBuilder bean.
Doing so will replace the auto-configured builder.
If you want any RestTemplateCustomizer beans to be applied to your custom builder, as the auto-configuration would have done, configure it using a RestTemplateBuilderConfigurer.
The following example exposes a RestTemplateBuilder that matches what Spring Boot’s auto-configuration would have done, except that custom connect and read timeouts are also specified:
link:{docs-java}/features/resttemplate/customization/MyRestTemplateBuilderConfiguration.java[role=include]The most extreme (and rarely used) option is to create your own RestTemplateBuilder bean without using a configurer.
In addition to replacing the auto-configured builder, this also prevents any RestTemplateCustomizer beans from being used.