错误消息：无法获得连接，数据源无效："java.sql.SQLException: Cannot create JDBC driver of class '' for connect URL 'null'"

Question

我目前正在使用以下技术堆栈：intellj 14.1.5、Spring MVC、tomcat 8.0.28 和 mysql workbench 6.3。我正在尝试连接到我的数据库，但出现错误。我觉得问题出在我的 context.xml 文件上。感谢任何帮助。

我的 context.xml 文件是什么样的：

   <!-- maxTotal: Maximum number of database connections in pool. Make sure you
        configure your mysqld max_connections large enough to handle
        all of your db connections. Set to -1 for no limit.
        -->

   <!-- maxIdle: Maximum number of idle database connections to retain in pool.
        Set to -1 for no limit.  See also the DBCP documentation on this
        and the minEvictableIdleTimeMillis configuration parameter.
        -->

   <!-- maxWaitMillis: Maximum time to wait for a database connection to become available
        in ms, in this example 10 seconds. An Exception is thrown if
        this timeout is exceeded.  Set to -1 to wait indefinitely.
        -->

   <!-- username and password: MySQL username and password for database connections  -->

   <!-- driverClassName: Class name for the old mm.mysql JDBC driver is
        org.gjt.mm.mysql.Driver - we recommend using Connector/J though.
        Class name for the official MySQL Connector/J driver is com.mysql.jdbc.Driver.
        -->

   <!-- url: The JDBC connection url for connecting to your MySQL database.
        -->

   <Resource name="jdbc/TestDB" auth="Container" type="javax.sql.DataSource"
             maxTotal="100" maxIdle="30" maxWaitMillis="10000"
             username="root" password="1234" driverClassName="com.mysql.jdbc.Driver"
             url="jdbc:mysql://localhost:3306/module1"/>

我添加到 web.xml 的内容：

<resource-ref>
    <description>DB Connection</description>
    <res-ref-name>jdbc/TestDB</res-ref-name>
    <res-type>javax.sql.DataSource</res-type>
    <res-auth>Container</res-auth>
</resource-ref>

我的 jsp 文件是什么样的：

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%@ taglib uri="http://java.sun.com/jsp/jstl/sql" prefix="sql"%>
  <html>
      <body>
      <h1>Test1</h1>

       <sql:query var="rs" dataSource="jdbc/TestDB">
             select id from myguests
        </sql:query>

       <c:forEach var="row" items="${rs.rows}">
             ID: ${row.id}<br/>
        </c:forEach>

      </body>
   </html>

我的 pom.xml 文件中也有以下依赖项：

    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>5.1.37</version>
    </dependency>

Answer 1

我能够解决我的问题。看来我需要在 webapp 目录中创建一个 META-INF 目录。一旦我这样做了，我就把 context.xml 文件放在 META-INF 目录中，它纠正了这个问题。

错误消息：无法获得连接，数据源无效："java.sql.SQLException: Cannot create JDBC driver of class '' for connect URL 'null'"

Error Message: Unable to get connection, DataSource invalid: "java.sql.SQLException: Cannot create JDBC driver of class '' for connect URL 'null'"

mysql

tomcat

intellij-idea

web.xml

context.xml