服务器使用 Spring Boot 和 WebFlux 发送事件

Posted 2023-02-27

【中文标题】服务器使用 Spring Boot 和 WebFlux 发送事件

【英文标题】：Server Sent Events with Spring Boot and WebFlux

【发布时间】：2019-01-26 12:31:08

【问题描述】：

我正在处理服务器发送事件。我得到了帮助

http://sinhamohit.com/writing/spring-boot-reactive-sse

https://github.com/mohitsinha/spring-boot-reactive-sse

上述示例的问题是所有内容都定义在一个类中。我正在尝试做不同的课程，但它失败了，但有例外：

2018-08-20 17:03:15.521  WARN 10964 --- [           main] 
onfigReactiveWebServerApplicationContext : Exception encountered during 
context initialization - cancelling refresh attempt: 
org.springframework.context.ApplicationContextException: Unable to start 
reactive web server; nested exception is 
org.springframework.context.ApplicationContextException: Unable to start 
ReactiveWebApplicationContext due to missing ReactiveWebServerFactory bean.
2018-08-20 17:03:15.599 ERROR 10964 --- [           main] 
o.s.boot.SpringApplication               : Application run failed

org.springframework.context.ApplicationContextException: Unable to start 
reactive web server; nested exception is 
org.springframework.context.ApplicationContextException: Unable to start 
ReactiveWebApplicationContext due to missing ReactiveWebServerFactory bean.
at org.springframework.boot.web.reactive.context.ReactiveWebServerApplicationContext.onRefresh(ReactiveWebServerApplicationContext.java:76) ~[spring-boot-2.0.4.RELEASE.jar:2.0.4.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:544) ~[spring-context-5.0.8.RELEASE.jar:5.0.8.RELEASE]
at org.springframework.boot.web.reactive.context.ReactiveWebServerApplicationContext.refresh(ReactiveWebServerApplicationContext.java:61) ~[spring-boot-2.0.4.RELEASE.jar:2.0.4.RELEASE]
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:762) [spring-boot-2.0.4.RELEASE.jar:2.0.4.RELEASE]
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:398) [spring-boot-2.0.4.RELEASE.jar:2.0.4.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:330) [spring-boot-2.0.4.RELEASE.jar:2.0.4.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1258) [spring-boot-2.0.4.RELEASE.jar:2.0.4.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1246) [spring-boot-2.0.4.RELEASE.jar:2.0.4.RELEASE]
at hello.SpringBootApplication.main(SpringBootApplication.java:8) [classes/:na]

代码：

    <parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.0.4.RELEASE</version>
    </parent>

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

    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
    </dependency>
   </dependencies>


   @RestController
   @RequestMapping("/stock/transaction")
   public class StockTransactionController 

       @Autowired
       StockTransactionService stockTransactionService;

       @GetMapping(produces = MediaType.APPLICATION_STREAM_JSON_VALUE)
       public Flux<StockTransaction> stockTransactionEvents() 
           return stockTransactionService.getStockTransactions();
      
   

   @Service
   public class StockTransactionService 

     List<Stock> stockList = new ArrayList<>();
     List<String> stockNames = 
          Arrays.asList("mango,banana,guava,infinity".split(","));

     @Bean
     CommandLineRunner commandLineRunner() 
        return args -> 
        createRandomStock();
        stockList.forEach(System.out::println);
     ;
     

    public Flux<StockTransaction> getStockTransactions() 

    Flux<Long> interval = Flux.interval(Duration.ofSeconds(1));
    interval.subscribe((i) -> stockList.forEach(stock -> 
    stock.setPrice(changePrice(stock.getPrice()))));

    Flux<StockTransaction> stockTransactionFlux = Flux
            .fromStream(Stream.generate(() -> new 
    StockTransaction(getRandomUser(), getRandomStock(), new Date())));
    return Flux.zip(interval, stockTransactionFlux).map(Tuple2::getT2);
   
   

请帮忙。

【问题讨论】：

它看起来像是缺少/损坏的依赖项。您是从 IDE 还是命令行运行它？您可以尝试mvn dependency:purge-local-repository 并重新开始您的应用程序吗？

【参考方案1】：

问题出在注释上。 @SpringBootApplication