JDBC連接MySQL產生java.lang.ClassNotFoundException異常

最近JSP作業使用JDBC連接MySQL數據庫，將表單提交的數據存入本地MySQL數據庫，寫好了JDBCUtils類的增刪改差方法後，程序運行後發現數據一直無法插入數據庫，數據庫插入代碼如下：

public class JdbcUtils {

	// 數據庫用戶名
	private static final String USERNAME = "root";
	// 數據庫密碼
	private static final String PASSWORD = "root";
	// 驅動信息
	private static final String DRIVER = "com.mysql.jdbc.Driver";
	// 數據庫地址
	private static final String URL = "jdbc:mysql://localhost:3306/BookStore";

	private static Connection connection;
	private static Statement statement;

	// private PreparedStatement pstmt;
	// private ResultSet resultSet;

	public JdbcUtils() {
		try {
			Class.forName(DRIVER);
		} catch (ClassNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}

	/**
	 * 連接數據庫
	 * 
	 * @return
	 */
	public static Connection getConnection() {
		try {
			Class.forName(DRIVER);
			connection = DriverManager.getConnection(URL, USERNAME, PASSWORD);
			System.out.println(connection.toString());
		} catch (SQLException e) {
			System.out.println("the error is " + e.toString());
			e.printStackTrace();
		} catch (ClassNotFoundException e) {
			System.out.println("the exception is " + e.toString());
			e.printStackTrace();
		}
		return connection;
	}

	/**
	 * 插入數據庫
	 * 
	 * @param user
	 * @return
	 */
	public static boolean insert(User user) {

		getConnection(); // 連接數據庫

		// 數據庫插入操作
		try {
			String sql = "insert into info values(" + user.getUserName() + ", "
					+ user.getPwd() + ", " + user.getGender() + ", "
					+ user.getAge() + ", " + user.getAcademic() + ", "
					+ user.getHobbiesByString() + ", " + user.getSelfIntro()
					+ ")";
			if (connection != null) {
				statement = connection.createStatement();
				int i = statement.executeUpdate(sql);
				if (i > 0) {
					System.out.println("數據庫插入成功");
				} else {
					System.out.println("數據庫表插入失敗");
				}
			}

		} catch (SQLException e) {
			e.printStackTrace();
		} finally {
			System.out.println(connection == null ? "true" : "false");
			release(connection, statement);
		}
		return false;
	}

	/**
	 * 釋放資源
	 * 
	 * @param conenction
	 * @param statement
	 */
	public static void release(Connection conenction, Statement statement) {
		try {
			if (statement != null) {
				statement.close();
			}
			if (connection != null) {
				connection.close();
			}
		} catch (SQLException e) {
			e.printStackTrace();
		}
	}
}

控制檯打印信息如下：

the exception is java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
	at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1856)
	at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1705)
	at java.lang.Class.forName0(Native Method)
	at java.lang.Class.forName(Class.java:191)
	at com.cooffee.util.JdbcUtils.getConnection(JdbcUtils.java:45)
	at com.cooffee.util.JdbcUtils.insert(JdbcUtils.java:60)
	at com.cooffee.util.MyServlet.doPost(MyServlet.java:62)
	at com.cooffee.util.MyServlet.doGet(MyServlet.java:35)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:624)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:505)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:169)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
	at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:956)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:423)
	at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1079)
	at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:625)
	at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:318)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
	at java.lang.Thread.run(Thread.java:745)

可以看到，控制檯打印的錯誤是ClassNotFoundException，產生異常的原因是未找到com.mysql.jdbc.mysql中的類，所以我們只要將mysql-connector-java的jar包導入進來就好，注意，導入的tomcat中的lib文件夾。

報出該異常的原因還有可能是驅動包與MySQL的版本有關，找好對應的版本，該異常也會解決。