Question

我读过多篇关于NoClassDefFoundError的帖子，但没有找到令人满意的答案。

我开始学习hibernate。我编写了简单的应用程序来保存我的数据库中的Movie对象。

我成功地使用

编译了我的代码

javac -classpath ~/cp/hibernate-release-5.0.1.Final/lib/required/hibernate-core-5.0.1.Final.jar -d classes justhibernate/BasicMovieManager.java  justhibernate/Movie.java

但是，当我尝试使用

运行我的代码时

java -classpath ./:~/cp/hibernate-release-5.0.1.Final/lib/required/hibernate-core-5.0.1.Final.jar:./classes/ justhibernate.BasicMovieManager

我遇到了错误

Error: A JNI error has occurred, please check your installation and try again
Exception in thread "main" java.lang.NoClassDefFoundError: org/hibernate/service/ServiceRegistry
    at java.lang.Class.getDeclaredMethods0(Native Method)
    at java.lang.Class.privateGetDeclaredMethods(Class.java:2701)
    at java.lang.Class.privateGetMethodRecursive(Class.java:3048)
    at java.lang.Class.getMethod0(Class.java:3018)
    at java.lang.Class.getMethod(Class.java:1784)
    at sun.launcher.LauncherHelper.validateMainClass(LauncherHelper.java:544)
    at sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:526)
Caused by: java.lang.ClassNotFoundException: org.hibernate.service.ServiceRegistry
    at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    ... 7 more

我在hibernate.cfg.xml目录中有Movie.hbm.xml和./个文件。这是我的代码：

BasicMovieManager.java

package justhibernate;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
import org.hibernate.boot.registry.StandardServiceRegistry;
import org.hibernate.boot.MetadataSources;

public class BasicMovieManager 
{
    private SessionFactory sessionFactory = null;

    private void setUp() throws Exception
    {
        final StandardServiceRegistry registry = new StandardServiceRegistryBuilder()
                .configure() 
                .build();
        try 
        {
            sessionFactory = new MetadataSources( registry )
                .buildMetadata().buildSessionFactory();
        }
        catch (Exception e) 
        {
            StandardServiceRegistryBuilder.destroy( registry );
        }
    }

    private void persistMovie(Movie movie) 
    {
        if(sessionFactory == null) 
        {
            try {setUp();}
            catch(Exception e){e.printStackTrace();}
        }   
        Session session = sessionFactory.openSession();
        session.beginTransaction();
        session.save(movie);
        session.getTransaction().commit();
        session.close();
    }

    public static void main(String[] args)
    {
        BasicMovieManager bmm = new BasicMovieManager();
        Movie m = new Movie();
        m.setId(2);
        m.setTitle("Harry Potter and the Chamber of Secrets");
        m.setDirector("Steve Kloves");
        m.setSynopsis("2nd part od thunder-face magician");
        bmm.persistMovie(m);
    }
}

Movie.java

package justhibernate;

public class Movie
{
    private int id = 0;
    private String title = null;
    private String synopsis = null;
    private String director = null;

    public void setId(int id)
    {
        this.id = id;
    }

    public int getId()
    {
        return id;
    }

    public void setTitle(String title)
    {
        this.title = title;
    }

    public String getTitle()
    {
        return title;
    }

    public void setSynopsis(String synopsis)
    {
        this.synopsis = synopsis;
    }

    public String getSynopsis()
    {
        return synopsis;
    }

    public void setDirector(String director)
    {
        this.director = director;
    }

    public String getDirector()
    {
        return director;
    }
}

的hibernate.cfg.xml

<hibernate-configuration>
    <session-factory>

        <property name="connection.url">
            jdbc:mysql://localhost:3306/test
        </property>
        <property name="connection.driver_class">
            com.mysql.jdbc.Driver
        </property>
        <property name="connection.username">
            user
        </property>
        <property name="connection.password">
            password
        </property>
        <property name="dialect">
            org.hibernate.dialect.MySQL5Dialect
        </property>

        <mapping resource="Movie.hbm.xml" />

    </session-factory>
</hibernate-configuration>

Movie.hbm.xml

<hibernate-mapping>
    <class name="justhibernate.Movie" table="MOVIES">
        <id name="id" column="ID">
            <generator class="native" />
        </id>
        <property name="title" column="TITLE" />
        <property name="director" column="DIRECTOR" />
        <property name="synopsis" column="SYNOPSIS" />
    </class>
</hibernate-mapping>

Answer 1

看起来它是由Hibernate库的相对（以home符号〜开头）路径引起的。我试图用绝对路径运行你的代码，它成功找到了Hibernate。但请注意，如果没有指定MySQL JDBC，JBoss日志记录和其他必需库的路径，您的代码将无法运行，完整列表为here。

简单应用程序中的Hibernate NoClassDefFoundError

1 个答案: