org.apache.camel.FailedToStartRouteException: 由於空值，無法啟動路由 route1

Question

我是 apache 駱駝的新手。 我正在嘗試使用 json，將其轉換為 java 對象並使用管道分隔符將其寫入 CSV 文件中。 但是，在嘗試從另一個 api 的端點使用 json 時出現錯誤。 我正在使用 spring boot 來完成這個任務。

附上我正在嘗試的示例代碼。

@Component
public class HRFeedRoute extends RouteBuilder {

    @Override
    public final void configure() {
        System.out.println("fetching employee details from employee api");
        try {
            from("http://localhost:8083/getEmployee").startupOrder(1).to("direct:employee")
            .log("${body}");
                    
            from("direct:employee")
            .unmarshal().json(JsonLibrary.Jackson, Employee.class)
            .process(
                    ex -> {
                        System.out.println(ex);
                    });
            
        } catch(Error e) {
            System.out.println("Error occurred while processing employee data: "+e.getMessage());
        }
    }
}

org.apache.camel.FailedToStartRouteException: Failed to start route route1 because of null
    at org.apache.camel.impl.engine.RouteService.warmUp(RouteService.java:125)
    at org.apache.camel.impl.engine.InternalRouteStartupManager.doWarmUpRoutes(InternalRouteStartupManager.java:263)
    at org.apache.camel.impl.engine.InternalRouteStartupManager.safelyStartRouteServices(InternalRouteStartupManager.java:156)
    at org.apache.camel.impl.engine.InternalRouteStartupManager.doStartOrResumeRoutes(InternalRouteStartupManager.java:114)
    at org.apache.camel.impl.engine.AbstractCamelContext.doStartCamel(AbstractCamelContext.java:2809)
    at org.apache.camel.impl.engine.AbstractCamelContext.doStartContext(AbstractCamelContext.java:2657)
    at org.apache.camel.impl.engine.AbstractCamelContext.doStart(AbstractCamelContext.java:2620)
    at org.apache.camel.spring.boot.SpringBootCamelContext.doStart(SpringBootCamelContext.java:43)
    at org.apache.camel.support.service.BaseService.start(BaseService.java:115)
    at org.apache.camel.impl.engine.AbstractCamelContext.start(AbstractCamelContext.java:2452)
    at org.apache.camel.spring.SpringCamelContext.start(SpringCamelContext.java:121)
    at org.apache.camel.spring.SpringCamelContext.onApplicationEvent(SpringCamelContext.java:157)
    at org.springframework.context.event.SimpleApplicationEventMulticaster.doInvokeListener(SimpleApplicationEventMulticaster.java:172)
    at org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener(SimpleApplicationEventMulticaster.java:165)
    at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:139)
    at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:404)
    at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:361)
    at org.springframework.context.support.AbstractApplicationContext.finishRefresh(AbstractApplicationContext.java:898)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:554)
    at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:143)
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:758)
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:750)
    at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:397)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:315)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1237)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1226)
    at au.com.macquarie.hr.application.EmployeePackageBootApp.main(EmployeePackageBootApp.java:13)
Caused by: java.lang.UnsupportedOperationException: Cannot consume from http endpoint

Answer 1

錯誤信息的最后一行是關鍵：

Caused by: java.lang.UnsupportedOperationException: Cannot consume from http endpoint

camel-http和camel-http4 （對於 Camel 2.x）只能用作生產者，不能用作消費者。

您需要使用例如可以使用 http 請求的駱駝碼頭。

Answer 2

我找到了答案。 Jetty 將公開一個端點 URL，生產者將使用該 URL 發送 json/message。 所以在producer中添加jetty暴露的end poin url。 在 pom.xml Producer 中添加 camel-jetty-starter 依賴項：假設您知道其余 api 將如何將消息發布到另一個 api。 因此，我只是從控制器共享 postEntity 代碼。

ResponseEntity responseEntity = restTemplate.postForEntity(new URI("http://localhost:8084/employee-package/getEmployee"), request, Employee.class);

消費者 API 路由器：

@Component 公共類 HRFeedRoute 擴展了 RouteBuilder {

@Override
public final void configure() {
    System.out.println("fetching employee details from employee api");
    try {
        
        from("jetty://http://localhost:8084/employee-package/getEmployee")
        .log("${body}")
        .unmarshal().json(JsonLibrary.Jackson, Employee.class)
        .process(
                ex -> {
                    Employee employee = (Employee) ex.getIn().getBody();
                    System.out.println("|"+employee.getEmpId()+" | "+employee.getName()+" | "+employee.getDesignation()+" | "+employee.getSalary());
                });
        
    } catch(Error e) {
        System.out.println("Error occurred while processing employee data: "+e.getMessage());
    }
}

}