Javamail-为什么我无法使它正常工作？

Question

I stole this code to test about emailing using java. Javamail is required, obviously. For some reason, I can't get javax.mail to implement. I downloaded the most recent javamail and put them in the jdk and jre lib folders, yet nothing changes. Please and thank you!

 //A class which uses this file to send an email : 

import java.util.*;
import java.io.*;
import javax.mail.*;
import javax.mail.internet.*;

/**
* Simple demonstration of using the javax.mail API.
*
* Run from the command line. Please edit the implementation
* to use correct email addresses and host name.
*/
public final class Emailer {

  public static void main( String... aArguments ){
    Emailer emailer = new Emailer();
    //the domains of these email addresses should be valid,
    //or the example will fail:
    emailer.sendEmail(
      "sean_chili@yahoo.com", "clevelanm@sou.edu",
       "Testing 1-2-3", "blah blah blah"
    );
   }

  /**
  * Send a single email.
  */
  public void sendEmail(
    String aFromEmailAddr, String aToEmailAddr,
    String aSubject, String aBody
  ){
    //Here, no Authenticator argument is used (it is null).
    //Authenticators are used to prompt the user for user
    //name and password.
    Session session = Session.getDefaultInstance( fMailServerConfig, null );
    MimeMessage message = new MimeMessage( session );
    try {
      //the "from" address may be set in code, or set in the
      //config file under "mail.from" ; here, the latter style is used
      //message.setFrom( new InternetAddress(aFromEmailAddr) );
      message.addRecipient(
        Message.RecipientType.TO, new InternetAddress(aToEmailAddr)
      );
      message.setSubject( aSubject );
      message.setText( aBody );
      Transport.send( message );
    }
    catch (MessagingException ex){
      System.err.println("Cannot send email. " + ex);
    }
  }

  /**
  * Allows the config to be refreshed at runtime, instead of
  * requiring a restart.
  */
  public static void refreshConfig() {
    fMailServerConfig.clear();
    fetchConfig();
  }

  // PRIVATE //

  private static Properties fMailServerConfig = new Properties();

  static {
    fetchConfig();
  }

  /**
  * Open a specific text file containing mail server
  * parameters, and populate a corresponding Properties object.
  */
  private static void fetchConfig() {
    InputStream input = null;
    try {
      //If possible, one should try to avoid hard-coding a path in this
      //manner; in a web application, one should place such a file in
      //WEB-INF, and access it using ServletContext.getResourceAsStream.
      //Another alternative is Class.getResourceAsStream.
      //This file contains the javax.mail config properties mentioned above.
      input = new FileInputStream( "C:\\Temp\\MyMailServer.txt" );
      fMailServerConfig.load( input );
    }
    catch ( IOException ex ){
      System.err.println("Cannot open and load mail server properties file.");
    }
    finally {
      try {
        if ( input != null ) input.close();
      }
      catch ( IOException ex ){
        System.err.println( "Cannot close mail server properties file." );
      }
    }
  }
}

Answer 1

Just for completeness, here's the answer.

Your Eclipse is telling you

<Some Class> cannot be resolved to a type

This is usually an indication that your classpath is not correct. You said

I downloaded the most recent javamail and put them in the jdk and jre lib folders, yet nothing changes

Don't do this. Take the javamail.jar and use it on your application Build Path . To do so, drag and drop the jar into your project, right-click it and select Build Path > Add to build path .