部署在Tomcat上的Java应用程序无法连接到jdbc-mysql

Question

我正在尝试恢复我们的tomcat服务器，但是这个应用程序没有正确连接到MySQL。

这是发生了什么：

我有一个Java + Flex应用程序。 整个应用程序放在一个目录（不是.war文件）中。

$TOMCAT_WEBAPP/myflex_app/WEB-INF/lib/ -> JDBC mysql driver goes here.

这是我的应用程序配置：

    <database>
            <rpgByMoodle user="moodle" password="moodle">
                    <url>jdbc:mysql://localhost:3306/rpgbymoodle</url>
            </rpgByMoodle>
            <moodle user="moodle" password="moodle">
                    <url>jdbc:mysql://localhost:3306/moodle</url>
            </moodle>
    </database>

所以，我能够通过命令行客户端连接mysql，但应用程序没有。

我发现在互联网上人们告诉使用一些Netbeans（或Eclipse）菜单“添加新连接”..但是，我无法访问应用程序的源代码。

我在Linux上运行tomcat。 我已经检查了/var/log/tomcat6/的tomcat日志文件，并没有发现jdbc。

我的卡塔琳娜日志：

Aug 4, 2011 9:24:25 AM org.apache.catalina.core.StandardEngine start
INFO: Starting Servlet Engine: Apache Tomcat/6.0.20
Aug 4, 2011 9:24:26 AM org.apache.coyote.http11.Http11Protocol start
INFO: Starting Coyote HTTP/1.1 on http-8080
Aug 4, 2011 9:24:26 AM org.apache.catalina.startup.Catalina start
INFO: Server startup in 977 ms

Answer 1

尝试将JDBC jar文件放入tomcat-dir/common/lib并重启Tomcat。
比较问题在Tomcat中管理库 。

如果现在仍然有效，请从Tomcat日志文件中发布提取，查找连接而不是jdbc作为关键字。

Answer 2

我以前遇到过完全相同的问题并设法解决它。 Apache需要jdbc-msql的额外配置步骤。 首先，确保为SQL数据库设置了正确的GRANT权限。

接下来，按照他的解决方案进行操作： http ： //dev.mysql.com/doc/refman/5.0/en/connector-j-usagenotes-j2ee.html#connector-j-usagenotes-tomcat

首先，在$ CATALINA_HOME / common / lib中安装Connector / J附带的.jar文件，以便安装在容器中的所有应用程序都可以使用它。

接下来，通过在定义Web应用程序的上下文中向$ CATALINA_HOME / conf / server.xml添加声明资源来配置JNDI DataSource：

<Context ....>

...

<Resource name="jdbc/MySQLDB"
           auth="Container"
           type="javax.sql.DataSource"/>

<!-- The name you used above, must match _exactly_ here!

   The connection pool will be bound into JNDI with the name
   "java:/comp/env/jdbc/MySQLDB"
-->

<ResourceParams name="jdbc/MySQLDB">
<parameter>
  <name>factory</name>
  <value>org.apache.commons.dbcp.BasicDataSourceFactory</value>
</parameter>

<!-- Don't set this any higher than max_connections on your
     MySQL server, usually this should be a 10 or a few 10's
     of connections, not hundreds or thousands -->

<parameter>
  <name>maxActive</name>
  <value>10</value>
</parameter>

<!-- You don't want to many idle connections hanging around
     if you can avoid it, only enough to soak up a spike in
     the load -->

<parameter>
  <name>maxIdle</name>
  <value>5</value>
</parameter>

<!-- Don't use autoReconnect=true, it's going away eventually
     and it's a crutch for older connection pools that couldn't
     test connections. You need to decide whether your application
     is supposed to deal with SQLExceptions (hint, it should), and
     how much of a performance penalty you're willing to pay
     to ensure 'freshness' of the connection -->

<parameter>
  <name>validationQuery</name>
  <value>SELECT 1</value> <-- See discussion below for update to this option -->
</parameter>

<!-- The most conservative approach is to test connections
    before they're given to your application. For most applications
    this is okay, the query used above is very small and takes
    no real server resources to process, other than the time used
    to traverse the network.

    If you have a high-load application you'll need to rely on
    something else. -->

 <parameter>
  <name>testOnBorrow</name>
  <value>true</value>
 </parameter>

 <!-- Otherwise, or in addition to testOnBorrow, you can test
    while connections are sitting idle -->

  <parameter>
   <name>testWhileIdle</name>
   <value>true</value>
  </parameter>

 <!-- You have to set this value, otherwise even though
     you've asked connections to be tested while idle,
     the idle evicter thread will never run -->

 <parameter>
   <name>timeBetweenEvictionRunsMillis</name>
   <value>10000</value>
 </parameter>

 <!-- Don't allow connections to hang out idle too long,
     never longer than what wait_timeout is set to on the
     server...A few minutes or even fraction of a minute
     is sometimes okay here, it depends on your application
     and how much spikey load it will see -->

<parameter>
  <name>minEvictableIdleTimeMillis</name>
  <value>60000</value>
</parameter>

<!-- Username and password used when connecting to MySQL -->

<parameter>
 <name>username</name>
 <value>someuser</value>
</parameter>

<parameter>
 <name>password</name>
 <value>somepass</value>
</parameter>

<!-- Class name for the Connector/J driver -->

<parameter>
   <name>driverClassName</name>
   <value>com.mysql.jdbc.Driver</value>
</parameter>

<!-- The JDBC connection url for connecting to MySQL, notice
     that if you want to pass any other MySQL-specific parameters
     you should pass them here in the URL, setting them using the
     parameter tags above will have no effect, you will also
     need to use &amp; to separate parameter values as the
     ampersand is a reserved character in XML -->

<parameter>
  <name>url</name>
  <value>jdbc:mysql://localhost:3306/test</value>
</parameter>

Answer 3

如果您使用Eclipse Java EE运行Tomcat，
1）转到“服务器”选项卡
2）双击Tomcat服务器
3）在“常规信息”部分，单击“打开启动配置”。
4）转到Classpath选项卡并添加jdbc jar文件。
希望这个有用......为我工作。