tomcat - java.lang.ClassNotFoundException: com.servlets.QueryServletMv -
i keep getting error when run servlet on tomcat 7.0. seems cannot find problem is. code looks fine me.
here servlet.
package com.servlets; import java.io.ioexception; import java.io.printwriter; import java.sql.connection; import java.sql.drivermanager; import java.sql.resultset; import java.sql.sqlexception; import java.sql.statement; import javax.servlet.servletexception; import javax.servlet.annotation.webservlet; import javax.servlet.http.httpservlet; import javax.servlet.http.httpservletrequest; import javax.servlet.http.httpservletresponse; @webservlet("/querymvservlet") public class queryservletmv extends httpservlet { private static final long serialversionuid = 1l; public queryservletmv() { super(); } protected void doget(httpservletrequest request, httpservletresponse response) throws servletexception, ioexception { // set mime type response message response.setcontenttype("text/html"); //get output writer write response network printwriter out = response.getwriter(); connection conn = null; statement stmt = null; try { class.forname("com.mysql.jdbc.driver"); // step 1: create database "connection" object // mysql conn = drivermanager.getconnection("jdbc:mysql://localhost /ebookshop", "root", ""); // step 2: create "statement" object inside "connection" stmt = conn.createstatement(); // step 3: execute sql select query string[] authors = request.getparametervalues("author"); if(authors == null){ out.println("<h2>please go , select author</>"); return; } string sql = "select * books author in ("; sql +="'" + authors[0] + "'"; // first author (int = 1; < authors.length; i++ ){ sql += ", '" + authors[i] + "'"; } sql += ") , qty > 0 order author asc, title asc"; // print html page output of query out.println("<html><head><title></title></head><body>"); out.println("<h2>thank query. </h2>"); out.println("<p>your query is: " + sql + "</p>"); // send query server resultset rs = stmt.executequery(sql); // step 4: process query result int count = 0; while (rs.next()) { // print paragraph <p>....</p> each row out.println("<p>"+ rs.getstring("author") + ", " + rs.getstring("title") + ", $" + rs.getdouble("price") + "<p>"); ++count; } out.println("<p>==========" + count + " records found ======</p>"); out.println("</body></html>"); } catch (sqlexception ex) { ex.printstacktrace(); } catch (classnotfoundexception e) { e.printstacktrace(); } { out.close(); try { // step 5: close statement , connection if(stmt != null) stmt.close(); if(conn != null) conn.close(); } catch (sqlexception e) { e.printstacktrace(); } } } and here html page:
<html> <head> <title>yet e-bookshop mv</title> </head> <body> <h2>yet e-bookshop mv</h2> <form method="get" action="querymvservlet"> choose author: <br /><br /> <input type="checkbox" name="author" value="tan ah teck" />ah teck <input type="checkbox" name="author" value="mohammad ali" /> ali <input type="checkbox" name="author" value="kumar" />kumar <input type="checkbox" name="author" value="kevin jones" />kevin <input type="submit" value="search" /> </form> </body> </html> web.xml
<?xml version="1.0" encoding="utf-8"?> <web-app xmlns:xsi="http://www.w3.org/2001/xmlschema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemalocation="http://java.sun.com/xml/ns/javaee http://java.sun.com /xml/ns/javaee/web-app_3_0.xsd" id="webapp_id" version="3.0"> <servlet> <servlet-name>querybookmv</servlet-name> <servlet-class>com.servlets.queryservletmv</servlet-class> </servlet> <servlet-mapping> <servlet-name>querybookmv</servlet-name> <url-pattern>/querymvservlet</url-pattern> </servlet-mapping> </web-app> i classnotfoundexception yet have used correct package name. here stack trace
type exception report message error instantiating servlet class com.servlets.queryservletmv description server encountered internal error prevented fulfilling request. exception javax.servlet.servletexception: error instantiating servlet class com.servlets.queryservletmv org.apache.catalina.authenticator.authenticatorbase.invoke(authenticatorbase.java:504) org.apache.catalina.valves.errorreportvalve.invoke(errorreportvalve.java:103) org.apache.catalina.valves.accesslogvalve.invoke(accesslogvalve.java:950) org.apache.catalina.connector.coyoteadapter.service(coyoteadapter.java:421) org.apache.coyote.http11.abstracthttp11processor.process(abstracthttp11processor.java:1074) org.apache.coyote.abstractprotocol$abstractconnectionhandler.process(abstractprotocol.java:611) org.apache.tomcat.util.net.jioendpoint$socketprocessor.run(jioendpoint.java:316) java.util.concurrent.threadpoolexecutor.runworker(threadpoolexecutor.java:1142) java.util.concurrent.threadpoolexecutor$worker.run(threadpoolexecutor.java:617) org.apache.tomcat.util.threads.taskthread$wrappingrunnable.run(taskthread.java:61) java.lang.thread.run(thread.java:745) root cause java.lang.classnotfoundexception: com.servlets.queryservletmv org.apache.catalina.loader.webappclassloader.loadclass(webappclassloader.java:1720) org.apache.catalina.loader.webappclassloader.loadclass(webappclassloader.java:1571) org.apache.catalina.authenticator.authenticatorbase.invoke(authenticatorbase.java:504) org.apache.catalina.valves.errorreportvalve.invoke(errorreportvalve.java:103) org.apache.catalina.valves.accesslogvalve.invoke(accesslogvalve.java:950) org.apache.catalina.connector.coyoteadapter.service(coyoteadapter.java:421) org.apache.coyote.http11.abstracthttp11processor.process(abstracthttp11processor.java:1074) org.apache.coyote.abstractprotocol$abstractconnectionhandler.process(abstractprotocol.java:611) org.apache.tomcat.util.net.jioendpoint$socketprocessor.run(jioendpoint.java:316) java.util.concurrent.threadpoolexecutor.runworker(threadpoolexecutor.java:1142) java.util.concurrent.threadpoolexecutor$worker.run(threadpoolexecutor.java:617) org.apache.tomcat.util.threads.taskthread$wrappingrunnable.run(taskthread.java:61) java.lang.thread.run(thread.java:745)
the 404 or not found error message http standard response code indicating client able communicate given server, server not find requested.
the web site hosting server typically generate "404 not found" web page when user attempts follow broken or dead link; hence 404 error 1 of recognizable errors users can find on web.
first check whether server listing port number or not:
use localhost://portnumber
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