休眠 buildSessionFactory() 异常答案

【问题标题】：Hibernate buildSessionFactory() Exception休眠 buildSessionFactory() 异常
【发布时间】：2012-02-24 15:05:35
【问题描述】：

我有一个严重的休眠问题。我遵循了各种书籍和在线教程，但我得到了明显由 HibernateUtil.java 行抛出的相同异常“ExceptionInInitializerError”

SessionFactory sf = cfg.configure().buildSessionFactory();

我的 Tomcat 日志显示如下：

Caused by: java.lang.ExceptionInInitializerError
at de.marcelstuht.nerven2.server.HibernateUtil.buildSessionFactory(HibernateUtil.java:23)
at de.marcelstuht.nerven2.server.HibernateUtil.<clinit>(HibernateUtil.java:8)
at de.marcelstuht.nerven2.shared.model.Account.<init>(Account.java:52)
at de.marcelstuht.nerven2.server.GreetingServiceImpl.loginServer(GreetingServiceImpl.java:39)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at com.google.gwt.user.server.rpc.RPC.invokeAndEncodeResponse(RPC.java:569)
... 21 more

Caused by: org.hibernate.MappingException: Could not get constructor for org.hibernate.persister.entity.SingleTableEntityPersister
at org.hibernate.persister.internal.PersisterFactoryImpl.create(PersisterFactoryImpl.java:180)
at org.hibernate.persister.internal.PersisterFactoryImpl.createEntityPersister(PersisterFactoryImpl.java:131)
at org.hibernate.internal.SessionFactoryImpl.<init>(SessionFactoryImpl.java:345)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1737)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1775)
at de.marcelstuht.nerven2.server.HibernateUtil.buildSessionFactory(HibernateUtil.java:18)
... 29 more

Caused by: org.hibernate.InstantiationException: could not instantiate test objectde.marcelstuht.nerven2.shared.model.Account
at org.hibernate.engine.internal.UnsavedValueFactory.instantiate(UnsavedValueFactory.java:49)
at org.hibernate.engine.internal.UnsavedValueFactory.getUnsavedIdentifierValue(UnsavedValueFactory.java:68)
at org.hibernate.tuple.PropertyFactory.buildIdentifierProperty(PropertyFactory.java:75)
at org.hibernate.tuple.entity.EntityMetamodel.<init>(EntityMetamodel.java:143)
at org.hibernate.persister.entity.AbstractEntityPersister.<init>(AbstractEntityPersister.java:498)
at org.hibernate.persister.entity.SingleTableEntityPersister.<init>(SingleTableEntityPersister.java:142)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
at org.hibernate.persister.internal.PersisterFactoryImpl.create(PersisterFactoryImpl.java:158)
... 34 more

Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
at org.hibernate.engine.internal.UnsavedValueFactory.instantiate(UnsavedValueFactory.java:46)
... 44 more

Caused by: java.lang.NullPointerException
at de.marcelstuht.nerven2.shared.model.Account.<init>(Account.java:52)
... 49 more

帐户.java

package de.marcelstuht.nerven2.shared.model;

import java.io.Serializable;
import java.util.List;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;
import javax.validation.constraints.NotNull;

import org.apache.commons.codec.digest.DigestUtils;
import org.hibernate.Session;
import org.hibernate.criterion.*;

import de.marcelstuht.nerven2.server.HibernateUtil;

@Entity
@Table(name = "account")
public class Account implements Serializable {

private static final long serialVersionUID = 2675108132819989138L;

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(name = "id")
Long id;

@NotNull
    @Column(name = "username", unique = true)
String username;

@Column(name = "password")
String password;

@Column(name = "email")
String email;

protected Session session;


public Account() {
    session = HibernateUtil.getSessionFactory().openSession();
}

public Account(Long id) {
    this.id = id;
    session = HibernateUtil.getSessionFactory().openSession();
}

public Account(Long id, String username, String password, String email) {
    this.id = id;
    this.username = username;
    this.password = password;
    this.email = email;
    session = HibernateUtil.getSessionFactory().openSession();

}

public void setId(Long newid) {
    id = newid;
}

public Long getId() {
    return id;
}

public void setUsername(String user) {
    username = user;
}

public String getUsername() {
    return username;
}

public void setEmail(String mail) {
    email = mail;
}

public String getEmail() {
    return email;
}

public void setPassword(String newPass) {
    password = newPass;
}

public void setNewPassword(String newPass) {
    password = hashPassword(newPass);
}

public boolean checkPassword(String pass) {
    pass = hashPassword(pass);
    if (password.equals(pass)) return true;
    else return false;
}

private String hashPassword(String password) {
    return DigestUtils.shaHex("wudu390909dfh"+password);
}

public Account get(Long id) {
    session.beginTransaction();
    Account result = (Account) session.get("account", id);
    session.getTransaction().commit();
    return result;
}

public Long saveOrUpdate(Account account) {
    if (account == null) {
        return null;
    }

    session.beginTransaction();

    session.saveOrUpdate(account);
    Long id = (Long) session.getIdentifier(account);

    session.getTransaction().commit();
    return id;
}

public void delete(Account account) {
    if (account == null) {
        return;
    }
    session.beginTransaction();
    session.delete(account);
    session.getTransaction().commit();
}

public List<Account> getAccountByUsername(String user) {
    session.beginTransaction();

    @SuppressWarnings("unchecked")
    List<Account> result = session
            .createCriteria(Account.class)
            .add(Restrictions.eq("username", user))
            .list();
    session.getTransaction().commit();

    return result;
}

}

HibernateUtil.java

package de.marcelstuht.nerven2.server;

import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
import org.jboss.logging.Logger;

public class HibernateUtil {
private static final SessionFactory sessionFactory = buildSessionFactory();

protected HibernateUtil() {

}

private static SessionFactory buildSessionFactory() {
    try {
        // Create the SessionFactory from hibernate.cfg.xml
        Configuration cfg = new Configuration();
        SessionFactory sf = cfg.configure().buildSessionFactory();
        return sf;
    } catch (Exception ex) {
        // Make sure you log the exception, as it might be swallowed
        Logger.getLogger(HibernateUtil.class).error("Initial SessionFactory creation failed.", ex);
        throw new ExceptionInInitializerError(ex);
    }
}

public static SessionFactory getSessionFactory() {
    return sessionFactory;
}
}

hibernate.cfg.xml

<!DOCTYPE hibernate-configuration PUBLIC
    "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
    "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">

<hibernate-configuration>

<session-factory>

    <!-- Database connection settings -->
    <property name="connection.driver_class">com.mysql.jdbc.Driver</property>
    <property name="connection.url">jdbc:mysql://127.0.0.1:3306/ba</property>
    <property name="connection.username">*myuser*</property>
    <property name="connection.password">*mypassword*</property>

    <!-- JDBC connection pool (use the built-in) -->
    <property name="connection.pool_size">1</property>

    <!-- SQL dialect -->
    <property name="dialect">org.hibernate.dialect.MySQL5InnoDBDialect</property>

    <!-- Disable the second-level cache  -->
    <!-- <property name="cache.provider_class">org.hibernate.cache.internal.NoCacheProvider</property>-->

    <!-- Echo all executed SQL to stdout -->
    <property name="show_sql">true</property>

    <!-- Drop and re-create the database schema on startup -->        
    <property name="hibernate.bytecode.provider">javassist</property>

    <!-- Names the annotated entity class -->
    <mapping class="de.marcelstuht.nerven2.shared.model.Account"/>

</session-factory>

我尝试了 Hibernate 3.6.9 和 4.0.1（在不同的 Eclipse 项目中）。我添加到项目中的 JAR 的屏幕截图可在 Skitch 上找到：https://skitch.com/marcelstuht/g7h8h/properties-for-nerven2

【问题讨论】：

标签： hibernate hibernate-annotations

【解决方案1】：

使用者：java.lang.NullPointerException 在 de.marcelstuht.nerven2.shared.model.Account.(Account.java:52) ... 49 更多

从 Account 中的构造函数中删除任何内容。你有一个循环依赖。并且 Hibernate 对其 bean 使用 public no args consructor

HibernateUtil 加载
这会强制静态运行 buildSessionFactory
Hibernate 通过无参数实例化 Account
依次调用 HibernateUtil.....

相信我：没有代码的公共无参数构造函数，除了 POJO 设置器。没有别的了。

【讨论】：

我的问题不是加载的构造函数，而是实际上是循环依赖。我有一个 SesssionFactory 的静态初始化程序，但是，我的一个实体有一个需要设置 Query 的静态值。因此，Hibernate 无法初始化，因为该实体需要对其进行初始化......（已经很晚了......希望这是有道理的）。

【解决方案2】：

请检查 javassist.X.X.jar 是否在您的类路径中。

【讨论】：

【解决方案3】：

我以前遇到过这个问题。我最终发现，在注解装饰 getter 方法的实体中添加一个非注解方法，会让你陷入这种情况。如果您在字段周围而不是 getter 方法周围进行注释，那么您可以拥有额外的未映射方法。

【讨论】：

【解决方案4】：

我也遇到过“无法获得 org.hibernate.persister.entity.SingleTableEntityPersister 的构造函数”，将 javassist.X.X.jar 添加到类路径中就可以解决问题。

【讨论】：