1. Overview
This quick tutorial will show how to send a custom User-Agent header using Apache HttpClient.
2. Setting User-Agent on the HttpClient
We can set the User-Agent while configuring the client itself:
HttpClients.custom().setUserAgent("Mozilla/5.0 Firefox/26.0").build();
A full example would look like this:
@Test
void whenClientUsesCustomUserAgent_thenCorrect() throws IOException {
CloseableHttpClient client = HttpClients.custom()
.setUserAgent("Mozilla/5.0 Firefox/26.0")
.build();
final HttpGet request = new HttpGet(SAMPLE_URL);
String response = client.execute(request, new BasicHttpClientResponseHandler());
logger.info("Response -> {}", response);
}
3. Setting User-Agent on Individual Requests
A custom User-Agent header can also be set on individual requests, adding more flexibility to our client:
@Test
void whenRequestHasCustomUserAgent_thenCorrect() throws IOException {
CloseableHttpClient client = HttpClients.createDefault();
final HttpGet request = new HttpGet(SAMPLE_URL);
request.setHeader(HttpHeaders.USER_AGENT, "Mozilla/5.0 Firefox/26.0");
String response = client.execute(request, new BasicHttpClientResponseHandler());
logger.info("Response -> {}", response);
}
4. Conclusion
This article illustrated how you can use the HttpClient to send requests with a custom User-Agent header – for example, to simulate the behaviour of a specific browser.
The implementation of all these examples and code snippets can be found in the GitHub project – this is an Eclipse-based project, so it should be easy to import and run as it is.
