Exception in thread "main" java.lang.NullPointerException,该如何处理

Exception in thread "main" java.lang.NullPointerException
搞了一天一宿了，求高手求救，我只是用SSH做了一个简单的注册，注册值我给的是死值，就是固定的，还是会出现这个异常，请高手来指点，谢谢

Exception in thread "main" java.lang.NullPointerException
at org.springframework.orm.hibernate3.support.HibernateDaoSupport.getSession(HibernateDaoSupport.java:142)
at dao.UserDAO.save(UserDAO.java:39)
at test.Test.main(Test.java:19)

[解决办法]
很明显啊。你里面有个值是空的。根本就没取到。 可能是session问题。
你打印或者设置断点看什么地方抛出的异常就好了。easy
[解决办法]

Java code

Session session = getSession();        Transaction tx = session.beginTransaction();        session.save(user)                tx.commit();        session.close();
[解决办法]
空值异常，你确定session里面有东西吗
[解决办法]
很简单
就是你没有注入sessionFactory
配置一下就ok了
[解决办法]
这是我的配置文件,你看一下吧,
XML code
<?xml version="1.0" encoding="UTF-8"?><beans xmlns="http://www.springframework.org/schema/beans"         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"         xmlns:aop="http://www.springframework.org/schema/aop"         xmlns:tx="http://www.springframework.org/schema/tx"         xsi:schemaLocation="            http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd             http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.5.xsd             http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.5.xsd">    <!-- ========================= GENERAL DEFINITIONS ========================= -->    <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource">        <property name="driverClassName" value="com.mysql.jdbc.Driver"/>        <property name="url" value="jdbc:mysql://localhost:3306/spring?useUnicode=true&amp;characterEncoding=utf8"/>        <property name="username" value="root"/>        <property name="password" value="123456"/>        <property name="maxActive" value="100"/>        <property name="maxIdle" value="30"/>        <property name="maxWait" value="1000"/>        <property name="defaultAutoCommit" value="true"/>        <property name="removeAbandoned" value="true"/>        <property name="removeAbandonedTimeout" value="60"/>        <property name="logAbandoned" value="true"/>    </bean>    <bean id="txManager" class="org.springframework.orm.hibernate3.HibernateTransactionManager">        <property name="dataSource" ref="dataSource"/>        <property name="sessionFactory" ref="sessionFactory"/>    </bean>    <tx:advice id="txAdvice" transaction-manager="txManager">        <!-- the transactional semantics... -->        <tx:attributes>            <!-- all methods starting with 'get' are read-only -->            <tx:method name="get*" read-only="true"/>            <tx:method name="load*" read-only="true"/>            <tx:method name="list*" read-only="true"/>            <!-- other methods use the default transaction settings (see below) -->            <tx:method name="*"/>        </tx:attributes>    </tx:advice>    <!-- ensure that the above transactional advice runs for any execution        of an operation defined by the FooService interface com.dtb.web.impl-->    <aop:config>        <aop:pointcut id="webServiceOperation" expression="execution(* impl..*.*(..))"/>        <aop:advisor advice-ref="txAdvice" pointcut-ref="webServiceOperation"/>    </aop:config></beans> 
 
[解决办法]
换成这样
this.getHibernateTemplate().getSessionFactory().getCurrentSession().clear();


[解决办法]
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package dao;

import org.hibernate.Session;
import org.springframework.orm.hibernate3.support.HibernateDaoSupport;

import vo.User;

public class UserDAO extends HibernateDaoSupport {
public void save(User user){
Session session = getSession();
session.clear();
session.save(user);
}
}
Session session = getSession();这句话这儿出异常了，不知道为什么