javax.servlet.ServletException: java.lang.NoClassDefFoundError: com/mysql/jdbc/Driver

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英文:

javax.servlet.ServletException: java.lang.NoClassDefFoundError: com/mysql/jdbc/Driver

问题

  1. 我正在尝试运行简单的代码与MySQL连接。我正在使用Eclipse和Tomcat。
  2. 我已经在Libraries中添加了mysql-connector-java-8.0.1.9.jar：
  4. Libraries-->mysql-->mysql-connector-java-8.0.1.9.jar
  6. 我已经花了几个小时来添加和移除mysql-connector-java-8.0.1.9.jar到构建路径，但无法让它运行。请帮忙。我需要在运行配置中添加任何内容吗？
  8. 这是Eclipse浏览器上的错误：
  10.     HTTP Status 500 – Internal Server Error
  11.     
  12.     异常报告类型
  13.     
  14.     消息 javax.servlet.ServletException: java.lang.NoClassDefFoundError: com/mysql/jdbc/Driver
  15.     
  16.     描述 服务器遇到了一个意外情况，阻止它完成请求。
  17.     
  18.     异常 
  19.     org.apache.jasper.JasperException: javax.servlet.ServletException: java.lang.NoClassDefFoundError: com/mysql/jdbc/Driver
  20.     	org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:599)
  21.     	org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:500)
  22.     	org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:395)
  23.     	org.apache.jasper.servlet.JspServlet.service(JspServlet.java:339)
  24.     	javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
  25.     	org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
  26.     
  27.     根本原因 
  28.     javax.servlet.ServletException: java.lang.NoClassDefFoundError: com/mysql/jdbc/Driver
  29.     	org.apache.jasper.runtime.PageContextImpl.doHandlePageException(PageContextImpl.java:917)
  30.     	org.apache.jasper.runtime.PageContextImpl.handlePageException(PageContextImpl.java:846)
  31.     	org.apache.jsp.regCheck_jsp._jspService(regCheck_jsp.java:129)
  32.     	org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:71)
  33.     	javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
  34.     	org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:477)
  35.     	org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:395)
  36.     	org.apache.jasper.servlet.JspServlet.service(JspServlet.java:339)
  37.     	javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
  38.     	org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
  39.     
  40.     根本原因 
  41.     java.lang.NoClassDefFoundError: com/mysql/jdbc/Driver
  42.     	compute.DB.con(DB.java:21)
  43.     	org.apache.jsp.regCheck_jsp._jspService(regCheck_jsp.java:100)
  44.     	org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:71)
  45.     	javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
  46.     	org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:477)
  47.     	org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:395)
  48.     	org.apache.jasper.servlet.JspServlet.service(JspServlet.java:339)
  49.     	javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
  50.     	org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
  51.     
  52.     根本原因 
  53.     java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
  54.     	org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1951)
  55.     	org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1794)
  56.     	compute.DB.con(DB.java:21)
  57.     	org.apache.jsp.regCheck_jsp._jspService(regCheck_jsp.java:100)
  58.     	org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:71)
  59.     	javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
  60.     	org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:477)
  61.     	org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:395)
  62.     	org.apache.jasper.servlet.JspServlet.service(JspServlet.java:339)
  63.     	javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
  64.     	org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
  65.     
  66.     请注意，根本原因的完整堆栈跟踪在服务器日志中可用。
  68. 这是控制台输出：
  70.     > Mar 16, 2020 4:57:27 PM org.apache.catalina.core.StandardContext reload
  71.     INFO: 正在重新加载名称为[/Mysql]的上下文
  72.     Mar 16, 2020 4:57:27 PM org.apache.catalina.core.StandardContext reload
  73.     INFO: 重新加载名称为[/Mysql]的上下文已完成
  74.     Mar 16, 2020 4:57:41 PM org.apache.catalina.core.StandardWrapperValve invoke
  75.     SEVERE: 在带有路径[/Mysql]的上下文中为servlet[jsp]提供服务时，抛出异常[javax.servlet.ServletException: java.lang.NoClassDefFoundError: com/mysql/jdbc/Driver]，根本原因为
  76.     java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
  77.     	at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1951)
  78.     	at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1794)
  79.     	at compute.DB.con(DB.java:21)
  80.     	at org.apache.jsp.regCheck_jsp._jspService(regCheck_jsp.java:100)
  81.     	at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:71)
  82.     	at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
  83.     	at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:477)
  84.     	at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:395)
  85.     	at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:339)
  86.     	at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
  87.     	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
  88.     	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
  89.     	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
  90.     	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
  91.     	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
  92.     	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219)
  93.     	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:110)
  94.     	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:492)
  95.     	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:165)
  96.     	at org.apache.catalina.valves
  98. <details>
  99. <summary>英文:</summary>
  101. I am trying to run simple code to connect with mysql. I m using eclipse and tomcat.
  102. I have added mysql-connector-java-8.0.1.9.jar in Libraries: 
  104. Libraries--&gt;mysql--&gt;mysql-connector-java-8.0.1.9.jar
  106. I have been at it for several hours adding and removing mysql-connector-java-8.0.1.9.jar to build path cannot get it running. Please help. Do I need to add any thing in run configuration??
  108. This is the error on eclipse browser: 
  110.     HTTP Status 500 – Internal Server Error
  111.     
  112.     
  113.     Type Exception Report
  114.     
  115.     Message javax.servlet.ServletException: java.lang.NoClassDefFoundError: com/mysql/jdbc/Driver
  116.     
  117.     Description The server encountered an unexpected condition that prevented it from fulfilling the request.
  118.     
  119.     Exception 
  120.     org.apache.jasper.JasperException: javax.servlet.ServletException: java.lang.NoClassDefFoundError: com/mysql/jdbc/Driver
  121.     	org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:599)
  122.     	org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:500)
  123.     	org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:395)
  124.     	org.apache.jasper.servlet.JspServlet.service(JspServlet.java:339)
  125.     	javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
  126.     	org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
  127.     
  128.     
  129.     
  130.     Root Cause 
  131.     javax.servlet.ServletException: java.lang.NoClassDefFoundError: com/mysql/jdbc/Driver
  132.     	org.apache.jasper.runtime.PageContextImpl.doHandlePageException(PageContextImpl.java:917)
  133.     	org.apache.jasper.runtime.PageContextImpl.handlePageException(PageContextImpl.java:846)
  134.     	org.apache.jsp.regCheck_jsp._jspService(regCheck_jsp.java:129)
  135.     	org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:71)
  136.     	javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
  137.     	org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:477)
  138.     	org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:395)
  139.     	org.apache.jasper.servlet.JspServlet.service(JspServlet.java:339)
  140.     	javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
  141.     	org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
  142.     
  143.     
  144.     
  145.     Root Cause 
  146.     java.lang.NoClassDefFoundError: com/mysql/jdbc/Driver
  147.     	compute.DB.con(DB.java:21)
  148.     	org.apache.jsp.regCheck_jsp._jspService(regCheck_jsp.java:100)
  149.     	org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:71)
  150.     	javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
  151.     	org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:477)
  152.     	org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:395)
  153.     	org.apache.jasper.servlet.JspServlet.service(JspServlet.java:339)
  154.     	javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
  155.     	org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
  156.     
  157.     
  158.     
  159.     Root Cause 
  160.     java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
  161.     	org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1951)
  162.     	org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1794)
  163.     	compute.DB.con(DB.java:21)
  164.     	org.apache.jsp.regCheck_jsp._jspService(regCheck_jsp.java:100)
  165.     	org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:71)
  166.     	javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
  167.     	org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:477)
  168.     	org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:395)
  169.     	org.apache.jasper.servlet.JspServlet.service(JspServlet.java:339)
  170.     	javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
  171.     	org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
  172.     
  173.     
  174.     
  175.     Note The full stack trace of the root cause is available in the server logs.
  177. This is the output in console: 
  179.     &gt; Mar 16, 2020 4:57:27 PM org.apache.catalina.core.StandardContext reload
  180.     INFO: Reloading Context with name [/Mysql] has started
  181.     Mar 16, 2020 4:57:27 PM org.apache.catalina.core.StandardContext reload
  182.     INFO: Reloading Context with name [/Mysql] is completed
  183.     Mar 16, 2020 4:57:41 PM org.apache.catalina.core.StandardWrapperValve invoke
  184.     SEVERE: Servlet.service() for servlet [jsp] in context with path [/Mysql] threw exception [javax.servlet.ServletException: java.lang.NoClassDefFoundError: com/mysql/jdbc/Driver] with root cause
  185.     java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
  186.     	at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1951)
  187.     	at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1794)
  188.     	at compute.DB.con(DB.java:21)
  189.     	at org.apache.jsp.regCheck_jsp._jspService(regCheck_jsp.java:100)
  190.     	at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:71)
  191.     	at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
  192.     	at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:477)
  193.     	at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:395)
  194.     	at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:339)
  195.     	at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
  196.     	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
  197.     	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
  198.     	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
  199.     	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
  200.     	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
  201.     	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219)
  202.     	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:110)
  203.     	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:492)
  204.     	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:165)
  205.     	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:104)
  206.     	at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:1025)
  207.     	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
  208.     	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:452)
  209.     	at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1195)
  210.     	at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:654)
  211.     	at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:319)
  212.     	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
  213.     	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
  214.     	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
  215.     	at java.base/java.lang.Thread.run(Thread.java:834)
  216.     
  217.     Try - 05 Trying to establish con in regCheck.jsp
  218.     Con method called Try 5A
  219.     Try 05a - Trying to connect
  223. This is DB.java: 
  226.  
  228.     package compute;
  229.     
  230.     import java.sql.Connection;
  231.     import java.sql.DriverManager;
  232.     import java.sql.Statement;
  233.     import java.sql.*;
  234.     
  235.     public class DB {
  236.     	
  237.     	
  238.     	final static String DB_URL = &quot;jdbc:mysql://localhost:3306/new&quot;;
  239.     	final static String USER = &quot;admin&quot;;
  240.     	final static String PASS = &quot;admin&quot;;
  241.     	
  242.     	public static Connection con() {
  243.     		System.out.println(&quot;Con method called Try 5A&quot;);
  244.     		Connection con;
  245.     		try {
  246.     			System.out.println(&quot;Try 05a - Trying to connect&quot;);
  247.     			DriverManager.registerDriver(new com.mysql.jdbc.Driver());
  248.     			con = DriverManager.getConnection(DB_URL, USER, PASS);
  249.     			System.out.println(&quot;Try 05a- con established &quot;);
  250.     			return con;
  251.     		}catch(Exception e) {
  252.     			System.out.println(e);
  253.     			return null;
  254.     		}
  255.     	}
  256.     
  257.     	public static Statement st() {
  258.     		Statement stmt;
  259.     		try {
  260.     			stmt=DB.con().createStatement();
  261.     			return null;
  262.     		}catch(Exception e) {
  263.     			System.out.println(e);
  264.     			return null;
  265.     		}
  266.     	}
  267.     }
  269. This is regCheck.jsp: 
  271.     &lt;%@page import=&quot;java.sql.Connection&quot; %&gt;
  272.     &lt;%@page import=&quot;compute.DB&quot; %&gt;
  273.     &lt;%@page import=&quot;java.sql.PreparedStatement&quot; %&gt;
  274.     
  275.     &lt;%@ page language=&quot;java&quot; contentType=&quot;text/html; charset=ISO-8859-1&quot;
  276.     pageEncoding=&quot;ISO-8859-1&quot;%&gt;
  277.     &lt;!DOCTYPE html&gt;
  278.     &lt;html&gt;
  279.     	&lt;head&gt;
  280.     		&lt;meta charset=&quot;ISO-8859-1&quot;&gt;
  281.     		&lt;title&gt;Insert title here&lt;/title&gt;
  282.     	&lt;/head&gt;
  283.     	&lt;body&gt;
  284.     		&lt;%
  285.     		String user = request.getParameter(&quot;username&quot;);
  286.     		System.out.println(&quot;Try - 05 Trying to establish con in regCheck.jsp&quot;);
  287.     		Connection con = DB.con();
  288.     		System.out.println(&quot;Preparing Statement in regCheck.jsp&quot;);
  289.     		PreparedStatement p = con.prepareStatement(&quot;Insert into register(username)values(?)&quot;);
  290.     
  291.     		p.setString(1,user);
  292.     		System.out.println(&quot;user::&quot; +user);
  293.     
  294.     		int R = p.executeUpdate();
  295.     		if(R!=0)
  296.     			response.sendRedirect(&quot;index.html&quot;);
  297.     		else
  298.     			response.sendRedirect(&quot;register.jsp&quot;);
  299.     
  300.     		%&gt;
  301.     
  302.     	&lt;/body&gt;
  303.     &lt;/html&gt;
  305. </details>
  308. # 答案1
  309. **得分**: 0
  311. JDBC驱动程序库在您的*运行时*CLASSPATH中丢失，即Tomcat在其中查找所需的类以执行已编译代码的CLASSPATH。
  313. <details>
  314. <summary>英文:</summary>
  316. The JDBC driver library is missing from your *runtime* CLASSPATH i.e. the CLASSPATH where Tomcat looks for the required classes in order to execute your compiled code.
  322. </details>
  326. # 答案2
  327. **得分**: 0
  329. 我将mysql-connector-java-8.0.19.jar添加到Tomcat 7.0/Lib中，现在它正常工作。
  330. 我从库中和所有地方都将它移除，它仍然可用。
  331. 我创建了一个新项目，使用相同的代码，而没有将mysql-connector-java-8.0.19.jar添加到任何库或构建路径中，它正常运行。
  332. 我在某个地方的YouTube上找到了将其添加到Tomcat的说明。
  334. <details>
  335. <summary>英文:</summary>
  337. I added mysql-connector-java-8.0.19.jar  to Tomcat 7.0/Lib and now it&#39;s working find. 
  338. I removed it from Library and everywhere and it works.
  339. I created new project with the same code and without adding mysql-connector-java-8.0.19.jar to any library or build path, it&#39;s running fine. 
  340. I found the instruction to add to tomcat somewhere on youtube. 
  342. </details>

huangapple
  • 本文由 发表于 2020年3月16日 22:12:05
  • 转载请务必保留本文链接：https://go.coder-hub.com/60707549.html
  • eclipse
  • java
  • mysql
  • tomcat
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