spring常见错误分析
现象1：
org.springframework.beans.factory.BeanCreationException: Error creating bean with name ''org.springframework.aop.support.DefaultPointcutAdvisor'' defined in null: Can''t resolve reference to bean ''txAdvice'' while setting property ''advice''; nested exception is
原因：缺少Spring开头的各种包，到Spring2.0 src中编译新的dist目录出来，拷贝全部的springxxx.jar到jpetstore/WEB-INF/lib下。OK。
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现象2：
org.springframework.beans.factory.BeanCreationException: Error creating bean with name ''sessionFactory'' defined in resource [/WEB-INF/dataAccessContext-hibernate.xml] of ServletContext: Instantiation of bean failed; nested exception is java.lang.NoClassDefFoundError: javax/transaction/TransactionManager
java.lang.NoClassDefFoundError: javax/transaction/TransactionManager
原因：缺少jta.jar，OK
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现象3：
java.lang.NoClassDefFoundError: org/dom4j/Attribute缺dom4j.jar
java.lang.NoClassDefFoundError: net/sf/ehcache/CacheException
缺ehcache.jar
java.lang.NoClassDefFoundError: net/sf/cglib/core/KeyFactory
缺cglib-full.jar
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现象4：
org.springframework.beans.factory.BeanCreationException: Error creating bean with name ''sessionFactory'' defined in resource [/WEB-INF/dataAccessContext-hibernate.xml] of ServletContext: Initialization of bean failed; nested exception is net.sf.hibernate.MappingException: could not instantiate id generator
net.sf.hibernate.MappingException: could not instantiate id generator
原因：
hbm中id字段的定义为没有定义的sequesce,修改为inc
name="id"
type="string"
column="userid"
>
// 原来是sequence.
这样就可以了。
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现象6：
org.springframework.beans.factory.BeanCreationException: Error creating bean with name ''/shop/addItemToCart.do'' defined in ServletContext resource [/WEB-INF/petstore-servlet.xml]: Can''t resolve reference to bean ''petStore'' while setting property ''petStore''; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No bean named ''petStore'' is defined
org.springframework.beans.factory.NoSuchBeanDefinitionException: No bean named ''petStore'' is defined原因：
我使用Struts作为action,当然就不需要使用Spring WEB framework,因此也不需要与之配套的配置文件例如,petstore-servlet.xml,
还有remote-servlet.xml ,但是Spring仍旧加载此两个文件，没办法，只好将此两个文件挪动到别的地方，但是又出现找不到这两个
文件的IO异常，没办法，只好又拷贝回来，然后把文件内容晴空。
终于好用了。
原因就是，只要你在web.xml中定义了这个servlet，他就要去找此servlet名字对应的配置文件（servletname-servlet.xml）,找不到就出错。ok，现在注释掉web.xml中名字为petstore的servlet定义和影色，删除petstore-servlet.xml文件，哈哈，这下不报告错误了。
同理，注释名字为remote的servlet，删除remote-servlet.xml后，重新启动tomcat，这下不报告任何错误了。呵呵。原来如此啊。
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现象：
java.lang.NullPointerException
srx.test.testhibernate.UserDAO.getAll(UserDAO.java:9)
srx.test.struts.action.UserAction.execute(UserAction.java:20)原因：
Action原来
UserDAO // 这个类OK
public class UserDAO extends HibernateDaoSupport {
public List getAll() {
return this.getHibernateTemplate().find("select aa from Account aa");
}
}
//这个类需要修改
public class UserAction extends ActionSupport {
UserDAO dao = new UserDAO();
List accounts = dao.getAll();
。。。
}
修改：
//UserDAO dao = new UserDAO(); WebApplicationContext wac = this.getWebApplicationContext();
UserDAO dao = (UserDAO) wac.getBean("userDAO");
