Tomcat 无法识别 MySQL .jar 库 [英] Tomcat does not recognize the MySQL .jar library

问题描述

我尝试了几种不同的方法，以便 Tomcat 在运行我的 Web 应用程序时加载 MySQL 驱动程序.我使用的是 Ubuntu 8.04，库来自 libmysql-java 包.它们位于如下所示的目录中:

<前>~$ ls/usr/share/java/mysql*/usr/share/java/mysql-connector-java-5.1.5.jar

我的 CLASSPATH 包含这个文件:

<前>~$ echo $CLASSPATH.:/usr/lib/jvm/java-6-sun/bin:/usr/local/tomcat/lib/servlet-api.jar:/usr/share/java/mysql-connector-java-5.1.5.jar

我什至在我的 Web 应用程序的 WEB-INF/lib/目录中放置了 .jar 文件的副本:

<前>/usr/local/tomcat/webapps/ohms/WEB-INF/lib$ lsmysql-connector-java-5.1.5.jar

进行这些更改后，我重新启动 Tomcat，重新编译我的类，再次重新启动 Tomcat.另外，我正在使用 import java.sql.*;

导入必要的库

但是，当它运行 Class.forName("com.mysql.jdbc.Driver" 行时，我仍然收到 java.lang.ClassNotFoundException: com.mysql.jdbc.Driver 错误").newInstance();

我在这里做错了什么?

解决方案

放在 TOMCAT_HOME/lib 中.(我似乎记得在旧版本的 Tomcat 上，它是 TOMCAT_HOME/server/lib?)

它不会在 WEB-INF/lib 中工作，因为容器需要访问库，也就是说，将它放在一个 Web 应用程序的类加载器中，而不是容器中.虽然我会想象 CLASSPATH 方法会起作用，但它不是执行此操作的标准方法.也许还有其他一些障碍阻止它工作.

I tried several different ways such that Tomcat loads the MySQL drivers when running my web application. I'm using Ubuntu 8.04, and the libraries come from the libmysql-java package. They are located in the directory shown below:

~$ ls /usr/share/java/mysql*
/usr/share/java/mysql-connector-java-5.1.5.jar

My CLASSPATH includes this file:

~$ echo $CLASSPATH
.:/usr/lib/jvm/java-6-sun/bin:/usr/local/tomcat/lib/servlet-api.jar:/usr/share/java/mysql-connector-java-5.1.5.jar

I even put a copy of the .jar file in my WEB-INF/lib/ directory in my web app:

/usr/local/tomcat/webapps/ohms/WEB-INF/lib$ ls
mysql-connector-java-5.1.5.jar

After making these changes, I restart Tomcat, re-compile my classes, restart Tomcat again. Also, I am importing the necessary libraries using import java.sql.*;

However I am still getting the java.lang.ClassNotFoundException: com.mysql.jdbc.Driver error when it runs the line Class.forName("com.mysql.jdbc.Driver").newInstance();

What am I doing wrong here?

解决方案

Put it in TOMCAT_HOME/lib. (I seem to recall that on older versions of Tomcat, it's TOMCAT_HOME/server/lib?)

It's not going to work in WEB-INF/lib since the container needs access to the library, and, that is putting it in the classloader of one web app, not the container. While I would have imagined the CLASSPATH approach would work, it's not the standard way to do this. Perhaps there is some other snag that's preventing it from working.

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