所以我一直有问题,MySQL Connector/J驱动程序没有正确加载在Tomcat 6.0.20上运行的Java Web Start应用程序。我已将MySQL连接器JAR文件复制到Tomcat的lib目录以及webapps/WEB-INF中的lib目录中。我还在JNLP文件中添加了对JAR文件的引用。经过一番研究后,我发现我还需要将一个节点添加到context.xml文件($ CATALINA_HOME/conf)中,我根据Tomcat 6语法完成了该节点。下面是XML文件的内容:MySQL连接器/ J问题
<Context>
<!-- Default set of monitored resources -->
<WatchedResource>WEB-INF/web.xml</WatchedResource>
<!-- Uncomment this to disable session persistence across Tomcat restarts -->
<!--
<Manager pathname="" />
-->
<!-- Uncomment this to enable Comet connection tacking (provides events
on session expiration as well as webapp lifecycle) -->
<!--
<Valve className="org.apache.catalina.valves.CometConnectionManagerValve" />
-->
<Resource name="jdbc/MySQLDB" auth="Container" driverClassName="com.mysql.jdbc.Driver"
maxActive="10" maxIdle="1" maxWait="500" type="javax.sql.DataSource"
url="jdbc:mysql://myServerName:3306/myDbName" username="myUserName"
password="myPassword>" />
</Context>
这里是我用来访问数据库的代码:
Connection con = null;
try {
sb.append("\nAbout to register JDBC driver\n");
Driver driver=new com.mysql.jdbc.Driver();
DriverManager.registerDriver(driver);
sb.append("About to create new instance of mysql jdbc driver\n");
Class.forName("com.mysql.jdbc.Driver").newInstance();
} catch (InstantiationException e) {
sb.append(e.getMessage());
e.printStackTrace();
} catch (IllegalAccessException e) {
sb.append(e.getMessage());
e.printStackTrace();
} catch (ClassNotFoundException e) {
sb.append(e.getMessage());
e.printStackTrace();
} catch (SQLException e) {
sb.append(e.getMessage());
e.printStackTrace();
} catch (Exception e) {
sb.append(e.getMessage());
e.printStackTrace();
} // end try-catch
try {
sb.append("About to create connection using DriverManager\n");
con = DriverManager.getConnection("jdbc:mysql://myServerName:3306/myDbName","myUserName", "myPassword");
// Make sure that connection instance isn't null before creating statement and executing query.
if (con != null) {
sb.append("About to create SQL statement using con.createStatement\n");
Statement st = con.createStatement();
sb.append("About to create ResultSet by executing query");
ResultSet rs = st.executeQuery("SELECT * FROM catissue_user");
sb.append("About to loop through ResultSet\n");
while(rs.next()) {
sb.append(rs.getString(2));
} // end of while
sb.append("\nAbout to close ResultSet, Statement and connection\n");
rs.close();
st.close();
con.close();
} else {
sb.append("There was a problem creating the connection:\n");
} // end if
} catch(SQLException exception) {
sb.append(exception.getMessage());
exception.printStackTrace();
} catch(Exception exception) {
sb.append(exception.getMessage());
exception.printStackTrace();
} // end try-catch
当我用蚂蚁从Eclipse或者从SSH执行代码,我得到的结果很好,所以我知道这不是连接URL的问题。但是,当我使用Web Start(jnlp文件)运行它时,当我单击按钮时,JFrame甚至不会打开。然而,我知道这对于事件监听器来说不是问题,因为代码可以很好地执行另外两种方式。我发现当驱动程序正在注册时会发生异常,但如果我不包含这些行,我会收到错误消息,提示“找不到合适的驱动程序”。有什么建议可以解决这个问题?