tomcat Server Error: java.lang.NullPointerException
Type Exception Report Description The server encountered an unexpected condition that prevented it from fulfilling the request. Exception java.lang.NullPointerException com.gxa.login.dbutils.DBUtils.executeQuery(DBUtils.java:26) com.gxa.login.dao.LoginDao.queryInfo(LoginDao.java:16) com.gxa.login.service.LoginService.login(LoginService.java:15) com.gxa.login.service.LoginServlet.doPost(LoginServlet.java:27) javax.servlet.http.HttpServlet.service(HttpServlet.java:661) javax.servlet.http.HttpServlet.service(HttpServlet.java:742) org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) Note The full stack trace of the root cause is available in the server logs.
An error is also reported in the console
Obviously, the driver was not found
java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
java.sql.SQLException: No suitable driver found for jdbc: mysql://localhost:3306
Solution: check whether the jar package is correctly placed under web/WEB-INF/lib
Add to the directory to correctly identify and use: