下面的錯誤實在是不知道怎麼改了 麻煩有大神能幫忙看一下
阿新 • • 發佈：2019-02-13
HTTP Status 500 – Internal Server Error
Type Exception Report
Message An exception occurred processing [login_dealwith.jsp] at line [21]
Description The server encountered an unexpected condition that prevented it from fulfilling the request.
Exception
org.apache.jasper.JasperException: An exception occurred processing [login_dealwith.jsp] at line [21]
18: Connection con = ConnDB.getConnection();
19: String sql = "SELECT * FROM user_info WHERE username='"+username+"' AND password = '"+password+"'";
20: String z_t = "UPDATE zhuangtai SET zhuangtai='1'";
21: ResultSet re = ConnDB.executeQuery(sql, con);
22: if(re.next()){
23: int result= ConnDB.executeUpdate(z_t,con);
24: %>
Stacktrace:
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:593)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:482)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:386)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:330)
javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
Root Cause
java.lang.NullPointerException com.hb.lianjie.ConnDB.executeQuery(ConnDB.java:37) org.apache.jsp.login_005fdealwith_jsp._jspService(login_005fdealwith_jsp.java:144) org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70) javax.servlet.http.HttpServlet.service(HttpServlet.java:741) org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:444) org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:386) org.apache.jasper.servlet.JspServlet.service(JspServlet.java:330) javax.servlet.http.HttpServlet.service(HttpServlet.java:741) org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
Note The full stack trace of the root cause is available in the server logs.