Tomcat7 HTTP Status 500 - Servlet execution threw an exception

问题

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


root cause 

java.lang.NoClassDefFoundError: org/apache/commons/lang/exception/NestableRuntimeException
    java.lang.ClassLoader.defineClass1(Native Method)
    java.lang.ClassLoader.defineClassCond(Unknown Source)
    java.lang.ClassLoader.defineClass(Unknown Source)
    java.security.SecureClassLoader.defineClass(Unknown Source)
    org.apache.catalina.loader.WebappClassLoader.findClassInternal(WebappClassLoader.java:2904)
    org.apache.catalina.loader.WebappClassLoader.findClass(WebappClassLoader.java:1173)
    org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1681)
    org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1559)
    Hello.doGet(Hello.java:42)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:728)


root cause 

java.lang.ClassNotFoundException: org.apache.commons.lang.exception.NestableRuntimeException
    org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1714)
    org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1559)
    java.lang.ClassLoader.defineClass1(Native Method)
    java.lang.ClassLoader.defineClassCond(Unknown Source)
    java.lang.ClassLoader.defineClass(Unknown Source)
    java.security.SecureClassLoader.defineClass(Unknown Source)
    org.apache.catalina.loader.WebappClassLoader.findClassInternal(WebappClassLoader.java:2904)
    org.apache.catalina.loader.WebappClassLoader.findClass(WebappClassLoader.java:1173)
    org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1681)
    org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1559)
    Hello.doGet(Hello.java:42)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:728)

note The full stack trace of the root cause is available in the Apache Tomcat/7.0.33 logs.

and My Coding Here

import java.io.IOException;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import java.io.*;

import java.sql.*;

import net.sf.json.JSONArray;

import net.sf.json.JSONObject;
/**
 * Servlet implementation class Getting_data
 */

public class Hello extends HttpServlet {
    private static final long serialVersionUID = 1L;

    /**
     * @see HttpServlet#HttpServlet()
     */
    public Hello() {

    }
        public void doGet(HttpServletRequest req, HttpServletResponse res)
        throws ServletException, IOException
        {

            res.setContentType("text/html");
        PrintWriter pw = res.getWriter();
        Connection con;
        Statement stmt;
        ResultSet rs = null;
        try{
        Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
        con = DriverManager.getConnection("jdbc:odbc:Emp_info");
        stmt = con.createStatement();
        String query = "select * from Emp_table";// where employee_name='"+emp_name+"' or department='"+emp_dept+"' or email='"+email+"' order by employee_name";
        System.out.println("query " + query);
        rs = stmt.executeQuery(query);
        pw.println("Id"+"Name"+"Address"+"<br>");
       JSONArray arrayObj=new JSONArray();
        JSONArray arrayObj1=new JSONArray();
        JSONObject responseData = new JSONObject();
        while(rs.next())
        {
        //pw.println(rs.getString(1) + " " + rs.getString(2) + "<br>");
        String name = rs.getString(1);
        String name1 = rs.getString(2);
        arrayObj.add(new String(name));
        arrayObj1.add(new String(name1));
        }
        responseData.put("rows", arrayObj);
        responseData.put("data", arrayObj);
        pw.print(responseData);
        }


        catch (Exception e){
        pw.println(e);
        }
        }

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
    }

}

回答1:

Assuming your using Eclipse and the project configured as Dynamic Web Project Right click on your project --> choose configure build path --> now click on add jars button --> and select the Gson jar --> clickOK.

Republish the project and restart the server.

Else add the jar to WEB-INF\lib directoryinside the war

Or directly into the Deployed location in the tomcat , but in the same directory as mentioned

来源：https://stackoverflow.com/questions/13639068/tomcat7-http-status-500-servlet-execution-threw-an-exception