Proxool java.lang.NoClassDefFoundError [英] Proxool java.lang.NoClassDefFoundError

问题描述

我刚开始使用Proxool（JDBC连接池管理器）。我下载了在以下链接中找到的jar： http://proxool.sourceforge.net/download.html 。之后，我只是在NetBeans 7.0.1中将该jar位置添加到ClassPath中，构建了该项目，重新启动了我的服务器（即Glassfish），然后尝试配置它，如下例所示：

'p> https://java2s.com/Open-Source/Java/Database-JDBC-Connection-Pool/proxool/org/logicalcobwebs/proxool/ProxoolDataSourceTest.java.htm

我只是修改了示例（参数）来修复我的应用程序和下面的一段代码崩溃。它示出了误差 java.lang.NoClassDefFoundError：无法初始化类org.logicalcobwebs.proxool.ProxoolDataSource

我不明白为什么，因为我只是进口了整个包装。我不知道从哪里开始。

以下是我的代码：

  import org.logicalcobwebs.proxool。*; 
 import org.logicalcobwebs。*; 
 
 / *错误在这里----> * / ProxoolDataSource dataSource = new ProxoolDataSource（）; 
 dataSource.setAlias（flpool）; 
 dataSource.setDriver（com.mysql.jdbc.jdbc2.optional.MysqlConnectionPoolDataSource）; 
 dataSource.setDriverUrl（jdbc：mysql：// localhost：3306 / superdb）; 
 dataSource.setUser（db）; 
 dataSource.setPassword（password）; 
 dataSource.setMaximumActiveTime（100）; 
 dataSource.setMinimumConnectionCount（8）; 
 dataSource.setMaximumConnectionCount（25）; 
 Hashtable env = new Hashtable（）; 
 env.put（Context.INITIAL_CONTEXT_FACTORY，com.sun.jndi.rmi.registry.RegistryContextFactory）; 
 env.put（Context.PROVIDER_URL，rmi：// localhost：1099）; 
 Context context = new InitialContext（env）; 
 context.createSubcontext（jdbc）; 
 context.bind（jndiName，dataSource）; 
 context.close（）; 
 
 DataSource ds =（DataSource）context.lookup（jndiName）; 
 
 ProxoolFacade.removeConnectionPool（flpool）; 
 
 context.close（）; 
  

如果有人有任何想法，请提前致谢，感谢您的帮助。

解决方案

我猜你错过了 Apache Commons Logging JAR。

消息

 
无法初始化类org.logicalcobwebs.proxool.ProxoolDataSource 
 

表示指定类的静态初始化失败。

我下载了Proxool的源代码，并且此类中唯一的静态初始化为以下行：

  private static final Log LOG = LogFactory.getLog（ProxoolDataSource.class）; 
  

尝试将Commons Logging JAR添加到您的项目并重新启动服务器。

I just started using Proxool (JDBC Connection Pool manager). I downloaded the jar which is found at the following link: http://proxool.sourceforge.net/download.html. After that, I just added the jar location into the ClassPath in netbeans 7.0.1, built the project, restarted my server (which is Glassfish) and then tried to configure it as this example shows:

https://java2s.com/Open-Source/Java/Database-JDBC-Connection-Pool/proxool/org/logicalcobwebs/proxool/ProxoolDataSourceTest.java.htm

I just adapted the Example (parameters) to fix into my application and the following piece of code below crashes. It shows the error java.lang.NoClassDefFoundError: Could not initialize class org.logicalcobwebs.proxool.ProxoolDataSource.

I can't understand why because I just imported the whole package. I do not know where to start.

Here's my code:

import org.logicalcobwebs.proxool.*;
import org.logicalcobwebs.*;

/* Error Here ----> */ ProxoolDataSource dataSource = new ProxoolDataSource();
        dataSource.setAlias("flpool");
        dataSource.setDriver("com.mysql.jdbc.jdbc2.optional.MysqlConnectionPoolDataSource");
        dataSource.setDriverUrl("jdbc:mysql://localhost:3306/superdb");
        dataSource.setUser("db");
        dataSource.setPassword("password");
        dataSource.setMaximumActiveTime(100);
        dataSource.setMinimumConnectionCount(8);
        dataSource.setMaximumConnectionCount(25);
        Hashtable env = new Hashtable();
        env.put(Context.INITIAL_CONTEXT_FACTORY, "com.sun.jndi.rmi.registry.RegistryContextFactory");
        env.put(Context.PROVIDER_URL, "rmi://localhost:1099");
        Context context = new InitialContext(env);
        context.createSubcontext("jdbc");
        context.bind(jndiName,dataSource);
        context.close();          

    DataSource ds = (DataSource) context.lookup(jndiName);

    ProxoolFacade.removeConnectionPool("flpool");   

    context.close();

if someone have any idea will appreciate it your help, thanks in advance.

解决方案

I would guess that you are missing an Apache Commons Logging JAR.

The message

Could not initialize class org.logicalcobwebs.proxool.ProxoolDataSource

indicates that static initialization of the named class failed.

I downloaded the source of Proxool, and the only static initialization in this class was the following line:

private static final Log LOG = LogFactory.getLog(ProxoolDataSource.class);

Try adding a Commons Logging JAR to your project and restarting your server.

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