Using RestTemplate, how to send the request to a proxy first so I can use my junits with JMeter?

I have a web service running on my dev box implemented using Spring-MVC 3.0. I have various JUnits that test against that service using RestTemplate. What I would like to do is have JMeter pick up those JUnits REST requests when I run them. However, to do that, I need to have Spring's RestTemplate send them to the proxy that I'm running JMeter on. So, the question is, how can I do that?

I've done something similar with CXF and their http:conduit and http:client stuff, but I really have no idea how to do this with Spring-MVC.

@AHungerArtist's answer works for simple use cases, where you want all requests to use the same proxy. If you need some requests through restTemplate to use the proxy, and others to not, though, you may find this more useful. (Or if you just like doing it programmatically more than you like mucking with system properties!)

@Bean
public RestTemplate restTemplate() {
	SimpleClientHttpRequestFactory requestFactory = new SimpleClientHttpRequestFactory();
	
	Proxy proxy = new Proxy(Type.HTTP, new InetSocketAddress("my.host.com", 8080));
	requestFactory.setProxy(proxy);
	
	return new RestTemplate(requestFactory);
}

You should be able to create a copy of the restTemplate bean that way, and another one the normal way, so you can send requests with and without the proxy.

Sadly, this was really easy.

Properties props = System.getProperties();
props.put("http.proxyHost", "localhost");
props.put("http.proxyPort", "9080");

Spring has a good documentation using a Customizer to determine different proxy

public class ProxyCustomizer implements RestTemplateCustomizer {

	@Override
	public void customize(RestTemplate restTemplate) {
		final String proxyUrl = "proxy.example.com";
		final int port = 3128;

		HttpHost proxy = new HttpHost(proxyUrl, port);
		HttpClient httpClient = HttpClientBuilder.create().setRoutePlanner(new DefaultProxyRoutePlanner(proxy) {
			@Override
			protected HttpHost determineProxy(HttpHost target, HttpRequest request, HttpContext context)
					throws HttpException {
				if (target.getHostName().equals("gturnquist-quoters.cfapps.io")) {
					return super.determineProxy(target, request, context);
				}
				return null;
			}
		}).build();
		restTemplate.setRequestFactory(new HttpComponentsClientHttpRequestFactory(httpClient));

	}

}

and the call to apply the ProxyCustomizer is

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

Alternatively you can use runtime parameters:

jre -DproxySet=true -Dhttp.proxyHost=127.0.0.1 -Dhttp.proxyPort=8888

put these lines before calling your get or post method. so proxy get set .

    HttpComponentsClientHttpRequestFactory requestFactory = new HttpComponentsClientHttpRequestFactory();
    DefaultHttpClient httpClient = (DefaultHttpClient) requestFactory.getHttpClient();
    HttpHost proxy = new HttpHost("proxtserver", port);
    httpClient.getParams().setParameter(ConnRoutePNames.DEFAULT_PROXY,proxy);
    restTemplate.setRequestFactory(requestFactory);