少量線程
處理大量請(qǐng)求

你的系統(tǒng)
   ↓
WebClient
   ↓
支付寶接口 / 微信接口 / 第三方系統(tǒng)

線程發(fā)請(qǐng)求
↓
一直等待響應(yīng)
↓
線程被占用

線程發(fā)請(qǐng)求
↓
不用等待
↓
線程去處理別的任務(wù)
↓
響應(yīng)回來再通知

.block()

Mono<User> userMono = webClient.get()...
Mono<Order> orderMono = webClient.get()...

Mono.zip(userMono, orderMono)

restTemplate.exchange(...)

webClient.get()
         .uri("/user")
         .retrieve()
         .bodyToMono(User.class);

WebClient

瀏覽器客戶端

Mono<User>
Flux<User>

Mono<User>表示未來會(huì)返回一個(gè) User
Flux<User>表示未來會(huì)返回多個(gè) User

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-webflux</artifactId>
</dependency>

WebClient webClient = WebClient.create();

WebClient webClient = WebClient.create("https://api.example.com");

WebClient webClient = WebClient.builder()
        .baseUrl("https://api.example.com")
        .build();

@Configuration
public class WebClientConfig {
    @Bean
    public WebClient webClient() {
        //配置超時(shí)和日志
        HttpClient httpClient = HttpClient.create()
            .responseTimeout(Duration.ofSeconds(10))
            .wiretap(true);
        return WebClient.builder()
                //基本url域名
                .baseUrl("https://api.example.com")
            	//默認(rèn)請(qǐng)求頭增加類型為json
                .defaultHeader(HttpHeaders.CONTENT_TYPE,MediaType.APPLICATION_JSON_VALUE)
                //默認(rèn)請(qǐng)求頭增加token
        		.defaultHeader(HttpHeaders.AUTHORIZATION, "Bearer abcdefg")
            	//超時(shí)配置和日志
            	.clientConnector(new ReactorClientHttpConnector(httpClient))
                .build();
    }
}

@Bean
public WebClient webClient() {
    return WebClient.builder()
            .filter((request, next) -> {
                ClientRequest newRequest =
                        ClientRequest.from(request)
                                .header(HttpHeaders.AUTHORIZATION,"Bearer " + getToken())
                                .build();
                return next.exchange(newRequest);})
            .build();
}

@Autowired
private WebClient webClient;

GET /user?page=1&size=10

String result = webClient.get()
        .uri(uriBuilder -> uriBuilder
                .path("/user")
                .queryParam("page", 1)
                .queryParam("size", 10)
                .build())
        .headers(headers -> {
            headers.setBearerAuth(token);
            headers.add("appId", "1001");})
        .retrieve()
        .bodyToMono(String.class)
        .block();

https://api.example.com/user?page=1&size=10

webClient.get()

.uri("/user")

.retrieve()

.bodyToMono(String.class)

.block();

.block()

@Data
public class User {
    private Long id;
    private String name;
}

User user = webClient.get()
        .uri("/user")
        .retrieve()
        .bodyToMono(User.class)
        .block();

User user = webClient.get()
         .uri(uriBuilder -> uriBuilder
                .path("/user")
                .queryParam("page", 1)
                .queryParam("size", 10)
                .build())
        .headers(headers -> {
            headers.setBearerAuth(token);
            headers.add("appId", "1001");})
        .retrieve()
        .bodyToMono(User.class)
        .block();

POST /user
Content-Type: application/json

{
  "name":"張三",
  "password":"123",
}

@Data
public class UserReq {
    private String name;
    private String password;
}

UserReq req = new UserReq();
req.setName("張三");
req.setPassword("123");
String token = "Bearer xxxxxx";
String result = webClient.post()
        .uri("/user")
    	//JSON 請(qǐng)求
    	.contentType(MediaType.APPLICATION_JSON)
   		 //單次請(qǐng)求攜帶 Token. 可在配置類全局配置 Token
    	.header(HttpHeaders.AUTHORIZATION, token)
        .bodyValue(req)
        .retrieve()
        .bodyToMono(String.class)
        .block();

.contentType(MediaType.APPLICATION_FORM_URLENCODED)

把對(duì)象轉(zhuǎn)為請(qǐng)求體 JSON

{
  "name":"張三"
}

webClient.put()
        .uri("/user/1")
        .bodyValue(req)
        .retrieve()
        .bodyToMono(String.class)
        .block();

webClient.delete()
        .uri("/user/1")
        .retrieve()
        .bodyToMono(String.class)
        .block();

byte[] data = webClient.get()
        .uri("https://example.com/test.pdf")
        //如果需要攜帶token
    	.header(HttpHeaders.AUTHORIZATION,"Bearer xxxxxx")
        .retrieve()
        .bodyToMono(byte[].class)
        .block();

byte[] data = webClient.get()
        .uri("https://example.com/test.pdf")
    	//如果需要攜帶token
    	.header(HttpHeaders.AUTHORIZATION,"Bearer xxxxxx")
        .retrieve()
        .bodyToMono(byte[].class)
        .block();

Files.write(
        Paths.get("D:/test.pdf"),
        data
);

Flux<DataBuffer> flux = webClient.get()
        .uri("/download/file")
        .retrieve()
        .bodyToFlux(DataBuffer.class);
DataBufferUtils.write(
        flux,
        Paths.get("D:/big.zip"),
        StandardOpenOption.CREATE
).block();

webClient.get()
        .uri("https://example.com/big.zip")
        .retrieve()
        .bodyToFlux(DataBuffer.class)
        .map(DataBuffer::asByteBuffer)
        .doOnNext(buffer -> {
            // 寫入文件
        })
        .blockLast();

webClient.get()
        .uri("/user")
        .retrieve()
        .bodyToMono(String.class)

String result = webClient.get()
        .uri("/user")
        .retrieve()
        .onStatus(
                HttpStatusCode::is4xxClientError,
                response -> Mono.error(new RuntimeException("4xx異常"))
        )
        .onStatus(
                HttpStatusCode::is5xxServerError,
                response -> Mono.error(new RuntimeException("5xx異常"))
        )
        .bodyToMono(String.class)
        .block();

try {
    String result = webClient.get()
            .uri("/test")
            .retrieve()
            .bodyToMono(String.class)
            .block();
} catch (Exception e) {
    e.printStackTrace();
}

.retrieve()
.bodyToMono(...)

String result = webClient.get()
        .uri("/user")
        .exchangeToMono(response -> {
            if (response.statusCode().is2xxSuccessful()) {
                return response.bodyToMono(String.class);
            }
            return Mono.error(
                    new RuntimeException("請(qǐng)求失敗")
            );
        })
        .block();

RestTemplate / RestClient

webClient.get()

webClient.post()

.header()

.bodyValue()

.retrieve()
.bodyToMono()

.block()

@Service
public class HttpClientService {
    private final WebClient webClient;
    public HttpClientService(WebClient.Builder builder) {
        this.webClient = builder
                .baseUrl("https://api.example.com")
                .defaultHeader(HttpHeaders.CONTENT_TYPE,
                        MediaType.APPLICATION_JSON_VALUE)
                .build();
    }
    // GET
    public String getUser() {
        return webClient.get()
                .uri("/user/1")
                .retrieve()
                .bodyToMono(String.class)
                .block();
    }
    // POST
    public String login(LoginRequest request) {
        return webClient.post()
                .uri("/login")
                .bodyValue(request)
                .retrieve()
                .bodyToMono(String.class)
                .block();
    }
    // token請(qǐng)求
    public String getWithToken(String token) {
        return webClient.get()
                .uri("/user/info")
                .header(HttpHeaders.AUTHORIZATION,
                        "Bearer " + token)
                .retrieve()
                .bodyToMono(String.class)
                .block();
    }
}

Spring 官方現(xiàn)代 HTTP 客戶端

微服務(wù) + WebClient

Mono / Flux / Reactor