使用 JavaMail 的 ClassNotFoundException

Question

我在 Netbeans 中创建了一个新项目，我在其中设置了一个 servlet (Tomcat 8)，我想实现一种使用 gmail 发送电子邮件的方法。我找到了很多例子（比如 this）。我创建了一个 class

import java.util.Properties;
import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.PasswordAuthentication;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;

public class SendMail {

final String username = "mymail@gmail.com";
final String password = "pass";

public SendMail() {

}


public void send(){
    Properties props = new Properties();
    props.put("mail.smtp.auth", "true");
    props.put("mail.smtp.starttls.enable", "true");
    props.put("mail.smtp.host", "smtp.gmail.com");
    props.put("mail.smtp.port", "587");

    Session session = Session.getInstance(props,  //<- points1 here
      new javax.mail.Authenticator() {
            protected PasswordAuthentication getPasswordAuthentication() {
                    return new PasswordAuthentication(username, password);
            }
      });

    try {

            Message message = new MimeMessage(session);
            message.setFrom(new InternetAddress("from-email@gmail.com"));
            message.setRecipients(Message.RecipientType.TO,
                    InternetAddress.parse("to-email@gmail.com"));
            message.setSubject("Testing Subject");
            message.setText("Dear Mail Crawler,"
                    + "\n\n No spam to my email, please!");

            Transport.send(message);

            System.out.println("Done");

    } catch (MessagingException e) {
            throw new RuntimeException(e);
    }
}

}

我在 servlet 中调用了那个方法

SendMail send = new SendMail();
send.send();  //<- points 2

我得到一个错误：java.lang.ClassNotFoundException: com.sun.mail.util.MailLogger

org.apache.catalina.core.StandardWrapperValve.invoke Servlet.service() for servlet [MyServlet] in context with path [/MyServlet] threw exception [Servlet execution threw an exception] with root cause
 java.lang.ClassNotFoundException: com.sun.mail.util.MailLogger
    at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1295)
    at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1147)
    at javax.mail.Session.initLogger(Session.java:227)
    at javax.mail.Session.<init>(Session.java:212)
    at javax.mail.Session.getInstance(Session.java:248)
    at com.myPackage.MyServlet.SendMail.send(SendMail.java:35) //->points 1
    at com.myPackage.MyServlet.MyServlet.processRequest(MyServlet.java:77) //->points 2 
    at com.myPackage.MyServlet.MyServlet.doGet(MyServlet.java:266)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:618)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:725)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:393)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at com.myPackage.MyServlet.LogFilter.doFilter(LogFilter.java:22)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:142)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:610)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:537)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1085)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:658)
    at org.apache.coyote.http11.Http11NioProtocol$Http11ConnectionHandler.process(Http11NioProtocol.java:222)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1556)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1513)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:724)

我在我的项目中添加了 2 个罐子 javaee.jar 和 mail.jar。

Answer 1

您正在混合使用多个版本的 JavaMail。 javaee.jar only includes the API classes for compiling not execution. The mail.jar is going to be an old version of JavaMail. If you require just JavaMail then download the javax.mail.jar 并改用它。

使用 JavaMail 的 ClassNotFoundException

ClassNotFoundException using JavaMail

jakarta-mail

classnotfoundexception