spring5 webclient使用指南詳解

之前寫了一篇restTemplate使用實例，由於spring 5全面引入reactive，同時也有了restTemplate的reactive版webclient，本文就來對應展示下webclient的基本使用。

請求攜帶header

攜帶cookie

 @Test public void testWithCookie(){ Mono<String> resp = WebClient.create() .method(HttpMethod.GET) .uri("http://baidu.com") .cookie("token","xxxx") .cookie("JSESSIONID","XXXX") .retrieve() .bodyToMono(String.class); LOGGER.info("result:{}",resp.block()); }

攜帶basic auth

 @Test public void testWithBasicAuth(){ String basicAuth = "Basic "+ Base64.getEncoder().encodeToString("user:pwd".getBytes(StandardCharsets.UTF_8)); LOGGER.info(basicAuth); Mono<String> resp = WebClient.create() .get() .uri("http://baidu.com") .header(HttpHeaders.AUTHORIZATION,basicAuth) .retrieve() .bodyToMono(String.class); LOGGER.info("result:{}",resp.block()); }

設置全局user-agent

 @Test public void testWithHeaderFilter(){ WebClient webClient = WebClient.builder() .defaultHeader(HttpHeaders.USER_AGENT, "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/63.0.3239.132 Safari/537.36") .filter(ExchangeFilterFunctions .basicAuthentication("user","password")) .filter((clientRequest, next) -> { LOGGER.info("Request: {} {}", clientRequest.method(), clientRequest.url()); clientRequest.headers() .forEach((name, values) -> values.forEach(value -> LOGGER.info("{}={}", name, value))); return next.exchange(clientRequest); }) .build(); Mono<String> resp = webClient.get() .uri("https://baidu.com") .retrieve() .bodyToMono(String.class); LOGGER.info("result:{}",resp.block()); }

get請求

使用placeholder傳遞參數

@Test public void testUrlPlaceholder(){ Mono<String> resp = WebClient.create() .get() //多個參數也可以直接放到map中,參數名與placeholder對應上即可.uri("http://www.baidu.com/s?wd={key}&other={another}","北京天氣","test") //使用佔位符.retrieve() .bodyToMono(String.class); LOGGER.info("result:{}",resp.block()); }

使用uriBuilder傳遞參數

@Test public void testUrlBiulder(){ Mono<String> resp = WebClient.create() .get() .uri(uriBuilder -> uriBuilder .scheme("http") .host("www.baidu.com") .path("/s") .queryParam("wd", "北京天氣") .queryParam("other", "test") .build()) .retrieve() .bodyToMono(String.class); LOGGER.info("result:{}",resp.block()); }

post表單

@Test public void testFormParam(){ MultiValueMap<String, String> formData = new LinkedMultiValueMap<>(); formData.add("name1","value1"); formData.add("name2","value2"); Mono<String> resp = WebClient.create().post() .uri("http://www.w3school.com.cn/test/demo_form.asp") .contentType(MediaType.APPLICATION_FORM_URLENCODED) .body(BodyInserters.fromFormData(formData)) .retrieve().bodyToMono(String.class); LOGGER.info("result:{}",resp.block()); }

post json

使用bean來post

 static class Book { String name; String title; public String getName() { return name; } public void setName(String name) { this.name = name; } public String getTitle() { return title; } public void setTitle(String title) { this.title = title; } } @Test public void testPostJson(){ Book book = new Book(); book.setName("name"); book.setTitle("this is title"); Mono<String> resp = WebClient.create().post() .uri("http://localhost:8080/demo/json") .contentType(MediaType.APPLICATION_JSON_UTF8) .body(Mono.just(book),Book.class) .retrieve().bodyToMono(String.class); LOGGER.info("result:{}",resp.block()); }

直接post raw json

 @Test public void testPostRawJson(){ Mono<String> resp = WebClient.create().post() .uri("http://localhost:8080/demo/json") .contentType(MediaType.APPLICATION_JSON_UTF8) .body(BodyInserters.fromObject("{/n" + " /"title/" : /"this is title/",/n" + " /"author/" : /"this is author/"/n" + "}")) .retrieve().bodyToMono(String.class); LOGGER.info("result:{}",resp.block()); }

post二進制--上傳文件

@Test public void testUploadFile(){ HttpHeaders headers = new HttpHeaders(); headers.setContentType(MediaType.IMAGE_PNG); HttpEntity<ClassPathResource> entity = new HttpEntity<>(new ClassPathResource("parallel.png"), headers); MultiValueMap<String, Object> parts = new LinkedMultiValueMap<>(); parts.add("file", entity); Mono<String> resp = WebClient.create().post() .uri("http://localhost:8080/upload") .contentType(MediaType.MULTIPART_FORM_DATA) .body(BodyInserters.fromMultipartData(parts)) .retrieve().bodyToMono(String.class); LOGGER.info("result:{}",resp.block()); }

下載二進制

下載圖片

@Test public void testDownloadImage() throws IOException { Mono<Resource> resp = WebClient.create().get() .uri("http://www.toolip.gr/captcha?complexity=99&size=60&length=9") .accept(MediaType.IMAGE_PNG) .retrieve().bodyToMono(Resource.class); Resource resource = resp.block(); BufferedImage bufferedImage = ImageIO.read(resource.getInputStream()); ImageIO.write(bufferedImage, "png", new File("captcha.png")); }

下載文件

@Test public void testDownloadFile() throws IOException { Mono<ClientResponse> resp = WebClient.create().get() .uri("http://localhost:8080/file/download") .accept(MediaType.APPLICATION_OCTET_STREAM) .exchange(); ClientResponse response = resp.block(); String disposition = response.headers().asHttpHeaders().getFirst(HttpHeaders.CONTENT_DISPOSITION); String fileName = disposition.substring(disposition.indexOf("=")+1); Resource resource = response.bodyToMono(Resource.class).block(); File out = new File(fileName); FileUtils.copyInputStreamToFile(resource.getInputStream(),out); LOGGER.info(out.getAbsolutePath()); }

錯誤處理

@Test public void testRetrieve4xx(){ WebClient webClient = WebClient.builder() .baseUrl("https://api.github.com") .defaultHeader(HttpHeaders.CONTENT_TYPE, "application/vnd.github.v3+json") .defaultHeader(HttpHeaders.USER_AGENT, "Spring 5 WebClient") .build(); WebClient.ResponseSpec responseSpec = webClient.method(HttpMethod.GET) .uri("/user/repos?sort={sortField}&direction={sortDirection}", "updated", "desc") .retrieve(); Mono<String> mono = responseSpec .onStatus(e -> e.is4xxClientError(),resp -> { LOGGER.error("error:{},msg:{}",resp.statusCode().value(),resp.statusCode().getReasonPhrase()); return Mono.error(new RuntimeException(resp.statusCode().value() + " : " + resp.statusCode().getReasonPhrase())); }) .bodyToMono(String.class) .doOnError(WebClientResponseException.class, err -> { LOGGER.info("ERROR status:{},msg:{}",err.getRawStatusCode(),err.getResponseBodyAsString()); throw new RuntimeException(err.getMessage()); }) .onErrorReturn("fallback"); String result = mono.block(); LOGGER.info("result:{}",result); }

1. 可以使用onStatus根據status code進行異常適配
2. 可以使用doOnError異常適配
3. 可以使用onErrorReturn返回默認值

小結

webclient是新一代的async rest template，api也相對簡潔，而且是reactive的，非常值得使用。

以上就是本文的全部內容，希望對大家的學習有所幫助，也希望大家多多支持武林網。