【HTTP Status 500 - Servlet execution threw an exception】

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在网上翻了半天，终于在评论区发现了这个问题的解决方式，之所以报错是因为我创建Web项目时使用的是maven，而我把druid.properties这个文件随便放在一个包里，导致一直报错，正确做法是：使用maven需要把druid文件放到resources下面

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type Exception report

message Servlet execution threw an exception

description The server encountered an internal error that prevented it from fulfilling this request.

exception

javax.servlet.ServletException: Servlet execution threw an exception
	org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

root cause

java.lang.ExceptionInInitializerError
	web.servlet.login.UserDao.(UserDao.java:8)
	web.servlet.login.LoginServlet.doGet(LoginServlet.java:22)
	web.servlet.login.LoginServlet.doPost(LoginServlet.java:40)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:648)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
	org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

root cause

java.lang.NullPointerException
	java.util.Properties$LineReader.readLine(Properties.java:434)
	java.util.Properties.load0(Properties.java:353)
	java.util.Properties.load(Properties.java:341)
	web.servlet.login.JDBCUtils.(JDBCUtils.java:24)
	web.servlet.login.UserDao.(UserDao.java:8)
	web.servlet.login.LoginServlet.doGet(LoginServlet.java:22)
	web.servlet.login.LoginServlet.doPost(LoginServlet.java:40)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:648)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
	org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

note The full stack trace of the root cause is available in the Apache Tomcat/8.0.26 logs.
Apache Tomcat/8.0.26