JDBC连接MySQL产生java.lang.ClassNotFoundException异常

最近JSP作业使用JDBC连接MySQL数据库，将表单提交的数据存入本地MySQL数据库，写好了JDBCUtils类的增删改差方法后，程序运行后发现数据一直无法插入数据库，数据库插入代码如下：

public class JdbcUtils {

 // 数据库用户名
 private static final String USERNAME = "root";
 // 数据库密码
 private static final String PASSWORD = "root";
 // 驱动信息
 private static final String DRIVER = "com.mysql.jdbc.Driver";
 // 数据库地址
 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();
  }
 }

 /**
  * 连接数据库
  * 
  * @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;
 }

 /**
  * 插入数据库
  * 
  * @param user
  * @return
  */
 public static boolean insert(User user) {

  getConnection(); // 连接数据库

  // 数据库插入操作
  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("数据库插入成功");
    } else {
     System.out.println("数据库表插入失败");
    }
   }

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

 /**
  * 释放资源
  * 
  * @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();
  }
 }
}

控制台打印信息如下：

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，控制台打印的错误是ClassNotFoundException，产生异常的原因是未找到com.mysql.jdbc.mysql中的类，所以我们只要将mysql-connector-java的jar包导入进来就好，注意，导入的tomcat中的lib文件夹。

报出该异常的原因还有可能是驱动包与MySQL的版本有关，找好对应的版本，该异常也会解决。

JDBC连接MySQL产生java.lang.ClassNotFoundException异常

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