Question

我正在尝试使用servlet连接KafkaProducer并在eclipse中设置我的项目。但是当我运行KafkaProducer时，我得到一个例外：

org.apache.catalina.core.StandardWrapperValve调用SEVERE：上下文中的servlet [simple_kafka.SimpleProducer]的Servlet.service（）与路径[/ kafka_web]抛出异常[Servlet执行扔了一个异常]与根本原因java.lang.ClassNotFoundException： org.apache.kafka.clients.producer.KafkaProducer at org.apache.catalina.loader.WebappClassLoaderBase.loadClass（WebappClassLoaderBase.java:1291）在 org.apache.catalina.loader.WebappClassLoaderBase.loadClass（WebappClassLoaderBase.java:1119）在simple_kafka.SimpleProducer.doPost（SimpleProducer.java:56）at javax.servlet.http.HttpServlet.service（HttpServlet.java:661）at at javax.servlet.http.HttpServlet.service（HttpServlet.java:742）at at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter（ApplicationFilterChain.java:231）在 org.apache.catalina.core.ApplicationFilterChain.doFilter（ApplicationFilterChain.java:166）在 org.apache.tomcat.websocket.server.WsFilter.doFilter（WsFilter.java:52）在 org.apache.catalina.core.ApplicationFilterChain.internalDoFilter（ApplicationFilterChain.java:193）在 org.apache.catalina.core.ApplicationFilterChain.doFilter（ApplicationFilterChain.java:166）在 org.apache.catalina.core.StandardWrapperValve.invoke（StandardWrapperValve.java:199）在 org.apache.catalina.core.StandardContextValve.invoke（StandardContextValve.java:96）在 org.apache.catalina.authenticator.AuthenticatorBase.invoke（AuthenticatorBase.java:478）在 org.apache.catalina.core.StandardHostValve.invoke（StandardHostValve.java:140）在 org.apache.catalina.valves.ErrorReportValve.invoke（ErrorReportValve.java:81）在 org.apache.catalina.valves.AbstractAccessLogValve.invoke（AbstractAccessLogValve.java:650）在 org.apache.catalina.core.StandardEngineValve.invoke（StandardEngineValve.java:87）在 org.apache.catalina.connector.CoyoteAdapter.service（CoyoteAdapter.java:342）在 org.apache.coyote.http11.Http11Processor.service（Http11Processor.java:803）在 org.apache.coyote.AbstractProcessorLight.process（AbstractProcessorLight.java:66）在 org.apache.coyote.AbstractProtocol $ ConnectionHandler.process（AbstractProtocol.java:868）在 org.apache.tomcat.util.net.NioEndpoint $ SocketProcessor.doRun（NioEndpoint.java:1459）在 org.apache.tomcat.util.net.SocketProcessorBase.run（SocketProcessorBase.java:49）在 java.util.concurrent.ThreadPoolExecutor.runWorker（ThreadPoolExecutor.java:1149）在 java.util.concurrent.ThreadPoolExecutor中的$ Worker.run（ThreadPoolExecutor.java:624）在 org.apache.tomcat.util.threads.TaskThread $ WrappingRunnable.run（TaskThread.java:61）在java.lang.Thread.run（Thread.java:748）

我的KafkaProducerServlet如下：

package simple_kafka;

import java.io.IOException;
import java.util.Properties;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.kafka.clients.producer.KafkaProducer;
import org.apache.kafka.clients.producer.ProducerConfig;
//import org.apache.kafka.clients.producer.Producer;
import org.apache.kafka.clients.producer.ProducerRecord;

/**
 * Servlet implementation class SimpleProducer
 */
@WebServlet("/producer")
public class SimpleProducer extends HttpServlet {
    private static final long serialVersionUID = 1L;

    /**
     * @see HttpServlet#HttpServlet()
     */
    public SimpleProducer() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
//      response.getWriter().append("Served at: ").append(request.getContextPath());
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        doGet(request, response);
        response.getWriter().append("Served at: ").append(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG);
        String topicName = "ReplicaTopic";
          String key = "Key1";
          String value = "Value-1";

          Properties props = new Properties();
          props.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, "192.168.1.59:9092,192.168.1.59:9093");
          props.put("key.serializer","org.apache.kafka.common.serialization.StringSerializer");         
          props.put("value.serializer", "org.apache.kafka.common.serialization.StringSerializer");

          KafkaProducer<String, String> producer = new KafkaProducer <String, String>(props);
          try {
              ProducerRecord<String, String> record = new ProducerRecord<>(topicName,key,value);
              producer.send(record);           
              producer.close();
          }
          catch(Exception e) {
              response.getWriter().append("Exception at: ").append((CharSequence) e);
          }
//        response.sendRedirect("/consumer");
    }
}

我在项目属性的BuildPath中包含了JAR＆＃c>

Kafka 2.12-0.11.0.1.jar
卡夫卡的客户端 - 0.11.0.1.jar
SLF4J-API-1.7.25.jar

Answer 1

经过一天的搜索，我发现你需要包含JAR文件WEB-INF-＆gt; lib文件夹，您需要从eclipse＆amp;删除您的服务器重新配置它。在这之后，我能够运行KafkaProducer。

使用Servlet

1 个答案: