HTTP Status 500 java.lang.NoClassDefFoundError: org/springframework/jdbc/core/RowMapper_

org.springframework.beans.BeanInstantiationException: Failed to instantiate [demo.Words]:
No default constructor found; nested exception is java.lang.NoSuchMethodException: demo.Words.<init>()
或者是:

org.springframework.beans.BeanInstantiationException: Failed to instantiate [Daomain.User]: Is it an abstract class?; nested exception is java.lang.InstantiationException: Daomain.User

 

这个异常就是实体类的构造函数引起的  

解决方法:

要么不设置构造函数;

要么设置满参构造函数和空参函构造数;..

javax.servlet.ServletException: Servlet execution threw an exception org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)

root cause

java.lang.NoClassDefFoundError: org/springframework/jdbc/core/RowMapper
	AjaxTest.doGet(AjaxTest.java:23)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:622)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
	org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
这个是因为实体类字段跟数据库类型不一致造成的,把实体类类型改成跟数据库类型一样就好了 .