spring5 webclient使用指南详解

spring5 webclient使用指南详解

之前写了一篇restTemplate使用实例，由于spring 5全面引入reactive，同时也有了restTemplate的reactive版webclient，本文就来对应展示下webclient的基本使用。

请求携带header

携带cookie

@Test

public void testWithCookie(){

Mono 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());

}

携带basic auth

@Test

public void testWithBasicAuth(){

String basicAuth = "Basic "+ Base64.getEncoder().encodeToString("user:pwd".getBytes(StandardCharsets.UTF_8));

LOGGER.info(basicAXeWZnztuth);

Mono resp = WebClient.create()

.get()

.uri("http://baidu.com")

.header(HttpHeaders.AUTHORIZATION,basicAuth)

.retrieve()

.bodyToMono(String.class);

LOGGER.info("result:{}",resp.block());

}

设置全局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 resp = webClient.get()

.uri("https://baidu.com")

.retrieve()

.bodyToMono(String.class);

LOGGER.info("result:{}",resp.block());

}

get请求

使用placeholder传递参数

@Test

public void testUrlPlaceholder(){

Mono resp = WebClient.create()

.get()

//多个参数也可以直接放到map中,参数名与placeholder对应上即可

.uri("http://baidu.com/s?wd={key}&other={another}","北京天气","test") //使用占位符

.retrieve()

.bodyToMono(String.class);

LOGGER.info("result:{}",resp.block());

}

使用uriBuilder传递参数

@Test

public void testUrlBiulder(){

Mono resp = WebClient.create()

.get()

.uri(uriBuilder -> uriBuilder

.scheme("http")

.host("baidu.com")

.path("/s")

.queryParam("wd", "北京天气")

.queryParam("other", "test")

XeWZnzt .build())

.retrieve()

.bodyToMono(String.class);

LOGGER.info("result:{}",resp.block());

}

post表单

@Test

public void testFormParam(){

MultiValueMap formData = new LinkedMultiValueMap<>();

formData.add("name1","value1");

formData.add("name2","value2");

Mono resp = WebClient.create().post()

.uri("http://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来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 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 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二进制--上传文件

@Test

public void testUploadFile(){

HttpHeaders headers = new HttpHeaders();

headers.setContentType(MediaType.IMAGE_PNG);

HttpEntity entity = new HttpEntity<>(new ClassPathResource("parallel.png"), headers);

MultiValueMap parts = new LinkedMultiValueMap<>();

parts.add("file", entity);

Mono 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());

}

下载二进制

下载图片

@Test

public void testDownloadImage() throws IOException {

Mono resp = WebClient.create().get()

.uri("http://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"));

}

下载文件

@Test

public void testDownloadFile() throws IOException {

Mono 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());

}

错误处理

@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 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);

}

可以使用onStatus根据status code进行异常适配

可以使用doOnError异常适配

可以使用onErrorReturn返回默认值

小结

webclient是新一代的async rest template，api也相对简洁，而且是reactive的，非常值得使用。

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