使用 C3P0 运行 JBoss 7 服务器的 Eclipse 项目的 ClassNotFoundException

Question

I have a project in Eclipse that uses a JBoss server. I'm trying to change my database manager to use C3P0 . However, no matter what I've tried I can't seem to import the jar files correctly.

Here is the error I am getting:

javax.ejb.EJBException: Unexpected Error
    at org.jboss.as.ejb3.tx.CMTTxInterceptor.handleExceptionInOurTx(CMTTxInterceptor.java:157)
    at org.jboss.as.ejb3.tx.CMTTxInterceptor.invokeInOurTx(CMTTxInterceptor.java:213)
    at org.jboss.as.ejb3.tx.CMTTxInterceptor.required(CMTTxInterceptor.java:284)
    ...
Caused by: java.lang.NoClassDefFoundError: com/mchange/v2/c3p0/ComboPooledDataSource
    at com.softified.irw.common.DatabaseManager.<init>(DatabaseManager.java:24)
    at com.softified.irw.common.DatabaseManager.getDataSource(DatabaseManager.java:35)
    ...
Caused by: java.lang.ClassNotFoundException: com.mchange.v2.c3p0.ComboPooledDataSource from [Module "deployment.irw-ear.ear:main" from Service Module Loader]
    at org.jboss.modules.ModuleClassLoader.findClass(ModuleClassLoader.java:191)
    at org.jboss.modules.ConcurrentClassLoader.performLoadClassChecked(ConcurrentClassLoader.java:361)
    at org.jboss.modules.ConcurrentClassLoader.performLoadClassChecked(ConcurrentClassLoader.java:333)
    ...

Here's a portion of my code that is trying to reference the jar:

import com.mchange.v2.c3p0.ComboPooledDataSource;


public class DatabaseManager {
    private static ComboPooledDataSource cpds = null;
    private static DataSource dataSource = null;
    private static Connection connection = null;
    private DatabaseManager(String clientName) {
        try {
            cpds = new ComboPooledDataSource();
            cpds.setDriverClass( "com.mysql.jdbc.Driver" ); //loads the jdbc driver
            cpds.setJdbcUrl("java:jboss/datasources/" + clientName+"DS");
        } catch (Exception e) {
            // Handle error that it's not configured in JNDI.
            throw new RuntimeException("Client "+clientName + " datasource configuration is missing in JNDI!", e);
        }
    }

I know I'm probably not using c3p0 right, but I'm just trying to get past the class not found issue right now.

Here are the steps I took to import the jars:

1. Downloaded c3p0 libraries from here: http://sourceforge.net/projects/c3p0/?source=dlp
2. Made a folder 'lib' in the project referencing the library and copied the following files into it from the c3p0 download:
   • c3p0-0.9.5-pre8.jar
   • mchange-commons-java-0.2.7.jar
   • c3p0-oracle-thin-extras-0.9.5-pre8.jar (I know I probably don't need this one, but I added it anyways)
3. Right-clicked on each jar in Eclipse and hit "Build Path > Add to Build Path".
4. All three jars now show up in my "References Libraries"

My .classpath file has the following in it as a result:

<classpathentry kind="lib" path="lib/c3p0-0.9.5-pre8.jar" sourcepath="lib/c3p0-0.9.5-pre8-sources.jar"/>
<classpathentry kind="lib" path="lib/c3p0-oracle-thin-extras-0.9.5-pre8.jar"/>
<classpathentry kind="lib" path="lib/mchange-commons-java-0.2.7.jar" sourcepath="lib/mchange-commons-java-0.2.7-sources.jar"/>

I keep getting that same error message when I try accessing the relevant part of my code. It can't find the c3p0 class files. What am I doing wrong? Any help is much appreciated!

Answer 1

所有提到的三个 jars 复制并放置在 jboss 的 common lib 文件夹中并尝试，它会工作。一旦它解决了这个问题，那么你可以检查类加载器问题。

Answer 2

You need to put these jars in WEB-INF/lib folder OR add as Module in JBoss.

Easier way is to add these jars in WEB-INF/lib and try.

Answer 3

just add this dependency in your pom.xml :

<dependency>
    <groupId>c3p0</groupId>
    <artifactId>c3p0</artifactId>
    <version>0.9.1.2</version>
</dependency>

Answer 4

after adding jar in web-inf/lib. build jars then do following step

Right click on project ---> select "properties" --> Deployement assembly --> "ADD" option --> select "java build path entries" --> select path of c3p0 jar

**sandeep solanke