Java : NoClassDefFoundError: javax/activation/DataSource
Java : NoClassDefFoundError: javax/activation/DataSource
提问于 2012-12-20 20:46:32
我编写了一个小型Java命令行程序来测试从远程服务器发送电子邮件。我得到了可怕的"NoClassDefFoundError“，我不知道为什么。
服务器正在运行：
- SunOS 5.10 2005年1月通用
- Java 1.5.0_30-b03 ( Sun，标准)
我的java程序名为
SendEmailACME
错误信息是
Exception in thread "main" java.lang.NoClassDefFoundError: javax/activation/DataSource程序运行的全部输出是：
bash-3.00$ javac SendEmailACME.java
bash-3.00$ java SendEmailACME
SendEmailACME: Classpath: .:/users/steve/TestProgramsLib/mail.jar:users/steve/TestProgramsLib/activation.jar
DEBUG: setDebug: JavaMail version 1.4.4
Exception in thread "main" java.lang.NoClassDefFoundError: javax/activation/DataSource
at SendEmailACME.main(SendEmailACME.java:47)
bash-3.00$ 我跑了
java -verbose SendEmailACME
排水量太长，不能堆满。它所包含的只是常规输出，加上一堆关于java加载其所有常规库的消息，即来自mail.jar的库，但我没有看到javax.activation中的任何消息。
"$ echo $CLASSPATH“的输出是：
bash-3.00$ echo $CLASSPATH
.:/users/steve/TestProgramsLib/mail.jar:users/steve/TestProgramsLib/activation.jar
bash-3.00$我的主目录是
/users/steve它包含这两个目录。
- TestPrograms
- TestProgramsLib
第一个有我的程序SendEmailACME.java，SendEmailACME.class/第二个有下面的jars：
bash-3.00$ ls -l
total 1102
-rw-r--r-- 1 steve acme 55932 Apr 19 2006 activation.jar
-rw-r--r-- 1 steve acme 494975 Jan 14 2011 mail.jar
bash-3.00$这是我的命令行程序SendEmailACME的源代码：
import javax.mail.*;
import javax.mail.internet.*;
import javax.mail.Authenticator;
import javax.mail.PasswordAuthentication;
import java.util.Properties;
public class SendEmailACME {
public static void main(String[] args) throws Exception{
String smtpServer = "msg.abc.acme.com";
int port = 25;
String userid = "acme.staffdirectory";
String password = "password";
String contentType = "text/html";
String subject = "test: Send An Email, From A Java Client Using msg.abc.acme.com";
String from = "ACME.Staff.Directory@acme.com";
String to = "steve@acme.com,joerre123@gmail.com,fake.mail@acme.com,bogus@fauxmail.com";
String body = "<h1>Test. An Email, From A Java Client Using msg.abc.acme.com.</hi>";
System.out.println("SendEmailACME: Classpath: " + System.getProperty("java.class.path"));
Properties props = new Properties();
props.put("mail.transport.protocol", "smtp");
props.put("mail.smtp.auth", "true");
props.put("mail.smtp.starttls.enable","true");
props.put("mail.smtp.host", smtpServer);
Session mailSession = Session.getInstance(props);
// Get runtime more runtime output when attempting to send an email
mailSession.setDebug(true);
MimeMessage message = new MimeMessage(mailSession);
message.setFrom(new InternetAddress(from));
message.setRecipients(Message.RecipientType.TO, to);
message.setSubject(subject);
message.setContent(body,contentType);
Transport transport = mailSession.getTransport();
transport.connect(smtpServer, port, userid, password);
transport.sendMessage(message,message.getRecipients(Message.RecipientType.TO));
transport.close();
}// end function main()
}// end class SendEmailACME下面是运行命令以查看activation.jar中的内容的输出：
bash-3.00$ jar -tf activation.jar
META-INF/MANIFEST.MF
META-INF/SUN_MICR.SF
META-INF/SUN_MICR.RSA
META-INF/
META-INF/mailcap.default
META-INF/mimetypes.default
javax/
javax/activation/
javax/activation/ActivationDataFlavor.class
javax/activation/MimeType.class
javax/activation/MimeTypeParameterList.class
javax/activation/MimeTypeParseException.class
javax/activation/CommandInfo.class
javax/activation/DataHandler$1.class
javax/activation/DataHandler.class
javax/activation/DataSource.class
javax/activation/CommandMap.class
javax/activation/DataContentHandler.class
javax/activation/DataContentHandlerFactory.class
javax/activation/CommandObject.class
javax/activation/DataHandlerDataSource.class
javax/activation/DataSourceDataContentHandler.class
javax/activation/ObjectDataContentHandler.class
javax/activation/FileDataSource.class
javax/activation/FileTypeMap.class
javax/activation/MailcapCommandMap.class
javax/activation/MimetypesFileTypeMap.class
javax/activation/SecuritySupport$1.class
javax/activation/SecuritySupport$2.class
javax/activation/SecuritySupport$3.class
javax/activation/SecuritySupport$4.class
javax/activation/SecuritySupport$5.class
javax/activation/SecuritySupport.class
javax/activation/URLDataSource.class
javax/activation/UnsupportedDataTypeException.class
com/
com/sun/
com/sun/activation/
com/sun/activation/registries/
com/sun/activation/registries/MailcapFile.class
com/sun/activation/registries/MailcapParseException.class
com/sun/activation/registries/MimeTypeFile.class
com/sun/activation/registries/MimeTypeEntry.class
com/sun/activation/registries/LineTokenizer.class
com/sun/activation/registries/LogSupport.class
com/sun/activation/registries/MailcapTokenizer.class
com/sun/activation/viewers/
com/sun/activation/viewers/ImageViewer.class
com/sun/activation/viewers/ImageViewerCanvas.class
com/sun/activation/viewers/TextEditor.class
com/sun/activation/viewers/TextViewer.class
bash-3.00$所有的东西都编译得很好，但是它似乎找不到javax.activation.DataSource，尽管activation.jar在类路径中
我无法访问jdk_home/jre/lib/ext目录。
我一直试图从我的目录/user/steve/TestPrograms执行SendEmailACME
提前感谢您的帮助
史蒂夫
回答 2
Stack Overflow用户
回答已采纳
发布于 2012-12-20 22:05:21
bash-3.00$ echo $CLASSPATH
.:/users/steve/TestProgramsLib/mail.jar:users/steve/TestProgramsLib/activation.jar您似乎缺少了一个介于/和mail.jar:之间的users/steve。这意味着java找错了activation.jar的位置(在./users而不是/users中)。
Stack Overflow用户
发布于 2012-12-20 20:49:26
您的CLASSPATH不包含存放javax.*库的JDK库。
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/13980209
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