java - Spring @Component HttpGet 执行

Question

我有一个 Spring MVC 应用程序。问题是我无法执行 HttpGet 并在 @Component 类中接收响应。这是我的 @Component 类函数的样子:

private String getSite(String url) throws IOException, InterruptedException {
    HttpClient httpclient = HttpClients.createDefault();
    HttpGet httpget = new HttpGet(url);
    HttpResponse response = httpclient.execute(httpget); // This line causes the problem

    BufferedReader reader = new BufferedReader(new InputStreamReader(response.getEntity().getContent(), "UTF-8"));
    StringBuilder builder = new StringBuilder();
    for (String line = null; (line = reader.readLine()) != null; ) {
        builder.append(line).append("\n");
    }
    return builder.toString(); 
}

问题是，在控制台应用程序中工作得很好。这是我的 maven pom.xml(包括 httpComponents):

        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpclient</artifactId>
            <version>4.3.5</version>
        </dependency>

这是部署 Web 应用程序并加载第一页时收到的错误消息:

> HTTP Status 500 - Servlet.init() for servlet mvc-dispatcher threw
> exception
type Exception report
message Servlet.init() for servlet mvc-dispatcher threw exception
description The server encountered an internal error that prevented it from fulfilling this request.
exception javax.servlet.ServletException: Servlet.init() for servlet mvc-dispatcher threw exception

root cause java.lang.NoClassDefFoundError: org/apache/http/HttpEntity
root cause java.lang.ClassNotFoundException: org.apache.http.HttpEntity

org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1720)
    org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1571)
    java.lang.Class.getDeclaredConstructors0(Native Method)
    java.lang.Class.privateGetDeclaredConstructors(Class.java:2532)
    java.lang.Class.getDeclaredConstructors(Class.java:1901)
org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.determineCandidateConstructors(AutowiredAnnotationBeanPostProcessor.java:230)
org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.determineConstructorsFromBeanPostProcessors(AbstractAutowireCapableBeanFactory.java:976)
org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:949)
org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:490)
org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:461)
org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:295)
org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:223)
org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:292)
    org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194)
org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:607)
org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:932)
org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:479)
org.springframework.web.servlet.FrameworkServlet.configureAndRefreshWebApplicationContext(FrameworkServlet.java:647)
org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:598)
org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:661)
org.springframework.web.servlet.FrameworkServlet.initWebApplicationContext(FrameworkServlet.java:517)
    org.springframework.web.servlet.FrameworkServlet.initServletBean(FrameworkServlet.java:458)
    org.springframework.web.servlet.HttpServletBean.init(HttpServletBean.java:138)
    javax.servlet.GenericServlet.init(GenericServlet.java:158)
    org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501)
    org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
    org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)
    org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
    org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1070)
    org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:611)
    org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:314)
    java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    java.lang.Thread.run(Thread.java:745)

Answer 1

org.apache.http.HttpEntity 位于 httpcore 中。也将其添加到您的依赖项中。