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是什么原因导致Tomcat 7中不可序列化的异常？

java notserializableexception tomcat7
2022-09-02 02:21:47

我的 DAO 实现在使用 Tomcat7 启动服务器时引发不可序列化的异常。任何想法是什么原因造成的？我的其他DAO都没有这样做。

下面是类：

package com.project.dao;

import java.util.List;

import org.hibernate.SessionFactory;
import org.springframework.orm.hibernate3.HibernateTemplate;

import com.project.model.User;

public class UserDAOImpl implements UserDAO {
    private HibernateTemplate hibernateTemplate;

    public void setSessionFactory(SessionFactory sessionFactory) {
        this.hibernateTemplate = new HibernateTemplate(sessionFactory);
    }

    @Override
    public void saveUser(User user) {
        hibernateTemplate.saveOrUpdate(user);
    }

    @Override
    @SuppressWarnings("unchecked")
    public List<User> listUser() {
        return hibernateTemplate.find("from User");
    }

    @Override
    @SuppressWarnings("unchecked")
    public User getUserByID(long userID) {
        List<User> users= hibernateTemplate.find("from User where id = '" + userID + "'");
        return users.size() > 0 ? users.get(0) : null;
    }
}

这是我的配置：

<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:mvc="http://www.springframework.org/schema/mvc"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:aop="http://www.springframework.org/schema/aop"
    xmlns:context="http://www.springframework.org/schema/context"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
        http://www.springframework.org/schema/aop
        http://www.springframework.org/schema/aop/spring-aop-3.0.xsd
        http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context-3.0.xsd
        http://www.springframework.org/schema/mvc
        http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd">
    <bean id="myDataSource" 
    class="org.apache.tomcat.dbcp.dbcp.BasicDataSource">
      <property name="driverClassName">
        <value>com.mysql.jdbc.Driver</value>
      </property>
      <property name="url">
        <value>jdbc:mysql://localhost/context</value>
      </property>
      <property name="username">
        <value>someUser</value>
      </property>
      <property name="password">
        <value>somePassword</value>
      </property>
      <!-- Disable the second-level cache  -->
        <!-- Echo all executed SQL to stdout -->
    </bean>
    <bean id="sessionFactory" class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean">
        <property name="dataSource" ref="myDataSource" /> 
        <property name="annotatedClasses">
            <list>
                <value>com.project.model.User</value>
            </list>
        </property> 
        <property name="hibernateProperties">
        <props>
            <prop key="hibernate.dialect">org.hibernate.dialect.MySQLDialect</prop>
            <prop key="hibernate.show_sql">true</prop>
            <prop key="hibernate.show_sql">true</prop>
        </props>
        </property>
    </bean>
    <bean id="myUserDAO" class="com.project.dao.UserDAOImpl">
        <property name="sessionFactory" ref="sessionFactory"/>
    </bean> 
</beans>

这是我的堆栈：

SEVERE: IOException while loading persisted sessions: java.io.WriteAbortedException: writing aborted; java.io.NotSerializableException: com.news.dao.UserDAOImpl
java.io.WriteAbortedException: writing aborted; java.io.NotSerializableException: com.project.dao.UserDAOImpl

at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1332)
at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1946)
at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1870)
at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1752)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1328)
at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1946)
at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1870)
at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1752)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1328)
at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1946)
at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1870)
at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1752)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1328)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:350)
at org.apache.catalina.session.StandardSession.readObject(StandardSession.java:1600)
at org.apache.catalina.session.StandardSession.readObjectData(StandardSession.java:1073)
at org.apache.catalina.session.StandardManager.doLoad(StandardManager.java:284)
at org.apache.catalina.session.StandardManager.load(StandardManager.java:204)
at org.apache.catalina.session.StandardManager.startInternal(StandardManager.java:470)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5241)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:1033)
at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:774)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:1033)
at org.apache.catalina.core.StandardEngine.startInternal(StandardEngine.java:291)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
at org.apache.catalina.core.StandardService.startInternal(StandardService.java:443)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:727)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
at org.apache.catalina.startup.Catalina.start(Catalina.java:620)
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 org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:303)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:431)

Caused by: java.io.NotSerializableException: com.project.dao.UserDAOImpl
at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1164)
at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1518)
at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1483)
at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1400)
at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1158)
at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1518)
at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1483)
at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1400)
at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1158)
at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1518)
at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1483)
at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1400)
at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1158)
at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:330)
at org.apache.catalina.session.StandardSession.writeObject(StandardSession.java:1676)
at org.apache.catalina.session.StandardSession.writeObjectData(StandardSession.java:1090)
at org.apache.catalina.session.StandardManager.doUnload(StandardManager.java:411)
at org.apache.catalina.session.StandardManager.unload(StandardManager.java:353)
at org.apache.catalina.session.StandardManager.stopInternal(StandardManager.java:497)
at org.apache.catalina.util.LifecycleBase.stop(LifecycleBase.java:225)
at org.apache.catalina.core.StandardContext$4.run(StandardContext.java:5464)
at java.lang.Thread.run(Thread.java:662)
at org.apache.catalina.core.StandardContext.stopInternal(StandardContext.java:5481)
at org.apache.catalina.util.LifecycleBase.stop(LifecycleBase.java:225)
at org.apache.catalina.core.ContainerBase.stopInternal(ContainerBase.java:1072)
at org.apache.catalina.util.LifecycleBase.stop(LifecycleBase.java:225)
at org.apache.catalina.core.ContainerBase.stopInternal(ContainerBase.java:1072)
at org.apache.catalina.util.LifecycleBase.stop(LifecycleBase.java:225)
at org.apache.catalina.core.StandardService.stopInternal(StandardService.java:502)
at org.apache.catalina.util.LifecycleBase.stop(LifecycleBase.java:225)
at org.apache.catalina.core.StandardServer.stopInternal(StandardServer.java:748)
at org.apache.catalina.util.LifecycleBase.stop(LifecycleBase.java:225)
at org.apache.catalina.startup.Catalina.stop(Catalina.java:693)
at org.apache.catalina.startup.Catalina.start(Catalina.java:654)
... 6 more
Jul 31, 2011 9:27:21 PM org.apache.catalina.session.StandardManager startInternal

SEVERE: Exception loading sessions from persistent storage
java.io.WriteAbortedException: writing aborted; java.io.NotSerializableException: com.project.dao.UserDAOImpl
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1332)
at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1946)
at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1870)
at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1752)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1328)
at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1946)
at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1870)
at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1752)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1328)
at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1946)
at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1870)
at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1752)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1328)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:350)
at org.apache.catalina.session.StandardSession.readObject(StandardSession.java:1600)
at org.apache.catalina.session.StandardSession.readObjectData(StandardSession.java:1073)
at org.apache.catalina.session.StandardManager.doLoad(StandardManager.java:284)
at org.apache.catalina.session.StandardManager.load(StandardManager.java:204)
at org.apache.catalina.session.StandardManager.startInternal(StandardManager.java:470)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5241)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:1033)
at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:774)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:1033)
at org.apache.catalina.core.StandardEngine.startInternal(StandardEngine.java:291)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
at org.apache.catalina.core.StandardService.startInternal(StandardService.java:443)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:727)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
at org.apache.catalina.startup.Catalina.start(Catalina.java:620)
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 org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:303)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:431)

Caused by: java.io.NotSerializableException: com.project.dao.UserDAOImpl
at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1164)
at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1518)
at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1483)
at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1400)
at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1158)
at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1518)
at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1483)
at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1400)
at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1158)
at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1518)
at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1483)
at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1400)
at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1158)
at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:330)
at org.apache.catalina.session.StandardSession.writeObject(StandardSession.java:1676)
at org.apache.catalina.session.StandardSession.writeObjectData(StandardSession.java:1090)
at org.apache.catalina.session.StandardManager.doUnload(StandardManager.java:411)
at org.apache.catalina.session.StandardManager.unload(StandardManager.java:353)
at org.apache.catalina.session.StandardManager.stopInternal(StandardManager.java:497)
at org.apache.catalina.util.LifecycleBase.stop(LifecycleBase.java:225)
at org.apache.catalina.core.StandardContext$4.run(StandardContext.java:5464)
at java.lang.Thread.run(Thread.java:662)
at org.apache.catalina.core.StandardContext.stopInternal(StandardContext.java:5481)
at org.apache.catalina.util.LifecycleBase.stop(LifecycleBase.java:225)
at org.apache.catalina.core.ContainerBase.stopInternal(ContainerBase.java:1072)
at org.apache.catalina.util.LifecycleBase.stop(LifecycleBase.java:225)
at org.apache.catalina.core.ContainerBase.stopInternal(ContainerBase.java:1072)
at org.apache.catalina.util.LifecycleBase.stop(LifecycleBase.java:225)
at org.apache.catalina.core.StandardService.stopInternal(StandardService.java:502)
at org.apache.catalina.util.LifecycleBase.stop(LifecycleBase.java:225)
at org.apache.catalina.core.StandardServer.stopInternal(StandardServer.java:748)
at org.apache.catalina.util.LifecycleBase.stop(LifecycleBase.java:225)
at org.apache.catalina.startup.Catalina.stop(Catalina.java:693)
at org.apache.catalina.startup.Catalina.start(Catalina.java:654)
... 6 more

答案 1

发生这种情况是因为在代码中的某个位置，您正在会话中存储UserDAO（或者您正在存储具有对UserDAO引用的对象）。当您关闭 Tomcat 时，它会尝试序列化所有活动会话的完整对象图，然后在您启动备份时尝试还原它们。关键是Tomcat使用“正常”的java对象序列化，它要求所有对象都是。Serializable

如何补救：

  1. 不要在用户会话中存储不可序列化的对象（通常是一种很好的做法）。
  2. 使 UserDAO 可序列化。可能涉及实现接口并将你的休眠模板标记为我认为本身是可序列化的。如果您真的希望它工作，则可能必须添加一些代码，以便在反序列化时重新初始化hibernateTemplate。SerializabletransientHibernateTemplate
  3. 不要在您自己的应用程序或全局 tomcat 上下文中.xml Tomcat 序列化会话（添加到上下文中.xml在元素内的 conf/ 目录中。这可能是最适合您的操作过程，除非您确实需要在重新启动后保留会话。<Manager pathname="" /><Context>

答案 2

UserDaoImpl如果要序列化 java.io.Serializable 接口，则必须实现该接口（堆栈跟踪指示尝试将类的实例写入对象流）。

要序列化的实例以及该实例的对象图中的所有对象都必须是可序列化的。

从 Javadocs for Serializable，

类的可序列化性由实现java.io.Serializable接口的类启用...遍历图形时，可能会遇到不支持可序列化接口的对象。在这种情况下，将引发 NotSerializableException，它将标识不可序列化对象的类。

请注意，这些规则有例外。我建议您阅读 Java 对象序列化规范，以全面了解对象序列化何时发生，以及如何避免 NotSerializableException。


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