How to set multiple headers at once in Spring WebClient?

If those headers change on a per request basis, you can use:

webClient.get().uri("/resource").headers(httpHeaders -> {
    httpHeaders.setX("");
    httpHeaders.setY("");
});

This doesn’t save much typing; so for the headers that don’t change from one request to another, you can set those as default headers while building the client:

WebClient webClient = WebClient.builder().defaultHeader("...", "...").build();
WebClient webClient = WebClient.builder().defaultHeaders(httpHeaders -> {
    httpHeaders.setX("");
    httpHeaders.setY("");
}).build();