As described in Section 34.1, “RestTemplate Customization”, you can use a RestTemplateCustomizer with RestTemplateBuilder to build a customized RestTemplate. This is the recommended approach for creating a RestTemplate configured to use a proxy.

The exact details of the proxy configuration depend on the underlying client request factory that is being used. The following example configures HttpComponentsClientRequestFactory with an HttpClient that uses a proxy for all hosts except 192.168.0.5:

static class ProxyCustomizer implements RestTemplateCustomizer {

	@Override
	public void customize(RestTemplate restTemplate) {
		HttpHost proxy = new HttpHost("proxy.example.com");
		HttpClient httpClient = HttpClientBuilder.create().setRoutePlanner(new DefaultProxyRoutePlanner(proxy) {

			@Override
			public HttpHost determineProxy(HttpHost target, HttpRequest request, HttpContext context)
					throws HttpException {
				if (target.getHostName().equals("192.168.0.5")) {
					return null;
				}
				return super.determineProxy(target, request, context);
			}

		}).build();
		restTemplate.setRequestFactory(new HttpComponentsClientHttpRequestFactory(httpClient));
	}

}