oracle.jdbc.driver.OracleDriver ClassNotFoundExcep

问题:

This is my code for which I am getting error. My classes12.jar has been imported as an external jar.

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.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class LoginAction extends HttpServlet {
Connection conn;
Statement stmt;
ResultSet rs;
String query = "SELECT * FROM v_urja_login";
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    PrintWriter out = response.getWriter();
    out.println("Hello");
    String u_name = request.getParameter("uname");
    String u_pass = request.getParameter("upass");
    out.println(u_name);
    out.println(u_pass);
    try{
        Class.forName("oracle.jdbc.driver.OracleDriver");
        conn = DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:XE","urja","urja");
        stmt = conn.createStatement();
        rs = stmt.executeQuery(query);
    }catch(SQLException sex){
        sex.printStackTrace();
    } catch (ClassNotFoundException cnf) {
        cnf.printStackTrace();
    }
}
}

Stacktrace:

java.lang.ClassNotFoundException: oracle.jdbc.driver.OracleDriver
    at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1714)
    at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1559)
    at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:320
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Class.java:169)
    at LoginAction.doPost(LoginAction.java:27)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:647)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:931)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1004)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:310)
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
    at java.lang.Thread.run(Thread.java:619)

回答1:

   Class.forName("oracle.jdbc.driver.OracleDriver");

This line causes ClassNotFoundException, because you haven't placed ojdbc14.jar file in your lib folder of the project. or YOu haven't set the classpath of the required jar

回答2:

java.lang.ClassNotFoundException: oracle.jdbc.driver.OracleDriver

Just add the ojdbc14.jar to your classpath.

The following are the steps that are given below to add ojdbc14.jar in eclipse:

1) Inside your project

2) Libraries

3) Right click on JRE System Library

4) Build Path

5) Select Configure Build Path

6) Click on Add external JARs...

7) C:\oraclexe\app\oracle\product\10.2.0\server\jdbc\lib

8) Here you will get ojdbc14.jar

9) select here

10) open

11) ok

save and run the program you will get output.

回答3:

In Eclipse , rightclick on your application

Run As -> Run configurations -> select your server from type filter text box

Then in Classpath under Bootstrap Entries add your classes12.jar File and Click on Apply.
Now, run the file...... This worked for me !!

回答4:

Method 1: Download ojdbc.jar

add ojdbc6.jar to deployment assembly. Right click on project->properties->select deployment assembly->click on 'Add' ->select 'Archives from File System'->browse to the folder where ojdbc6.jar is saved.->add the jar->click finish->Apply/OK.

Method 2:

if you want to add ojdbc.jar to your maven dependencies you follow this link: http://www.mkyong.com/maven/how-to-add-oracle-jdbc-driver-in-your-maven-local-repository/ . . Even if you're using a maven project it is not necessary to add ojdbc to maven dependencies(method 2), method 1 (adding directly to deployment assembly) works just fine.

回答5:

try to add ojdbc6.jar or other version through the server lib "C:\apache-tomcat-7.0.47\lib",

Then restart the server in eclipse.

回答6:

1.Right click on your java project.

2.Select "RUN AS".

3.Select "RUN CONFIGURATIOS...".

4.Here select your server at left side of the page and then u would see "CLASS PATH" tab at riht side,just click on it.

5.Here clilck on "USER ENTRIES" and select "ADD EXTERNAL JARS".

6.Select "ojdbc14.jar" file.

7.Click on Apply.

8.Click on Run.

9.Finally Restart your server then it would be execute.

回答7:

In Eclipse,

When you use JDBC in your servlet, the driver jar must be placed in the WEB-INF/lib directory of your project.

回答8:

You can add a JAR which having above specified class exist e.g.ojdbc jar which supported by installed java version, also make sure that you have added it into classpath.