java - Servlet 错误 JDBC ClassNotFoundException

Question

我有一个登录页面。 用户提供用户名和通行证。 然后登录 sevlet 检查用户是否存在于 Db 中，如果不存在，则将用户名和密码发送到 ldap 服务器，如果用户存在于 ldap 服务器上，则在本地 mySql 数据库上创建新用户。

Servlet 工作正常 我可以看到 pass 和 usename 已发送到 TOMCAT。问题是当我尝试连接到 mySQL 数据库时。 这是代码:

package database;
import java.sql.*;


public class DbConnect {

    /**
     * Static method for user authentication
     * Test method
     * @param username - Username already striped from illigal chars (XSS safe)
     * @param pass - password
     */
    public static void connect(String username,String pass)//Consider changing void to boolean
    {
        Connection con;
        PreparedStatement st;
        ResultSet rs;
        try {
            //Register JDBC driver
            Class.forName("oracle.jdbc.OracleDriver");//Loading DB Driver
        } catch (ClassNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

        //Open a connection
        //  Database credentials
        final String USER = "root";
        final String PASS = "";
        final String DB_URL = "jdbc:mysql://localhost:3306/imf_jsp";
        try {
             con = DriverManager.getConnection(DB_URL,USER,PASS);
             st = con.prepareStatement("SELECT * FROM user WHERE signum = ? AND pass_hash = ?"); //Find user with given username & pass
             st.setString(1, username);//Bind param (Should prevent SQL Injection? Not sure but it is working in PHP with PDO)
             st.setString(2, pass);//Bind param (Should prevent SQL Injection? Not sure but it is working in PHP with PDO)
             st.execute();//statemant execution
             System.out.println("In Database?: " + st);//If not then check in LDAP
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        }
    }

这是 StackTrace:

java.lang.ClassNotFoundException: oracle.jdbc.OracleDriver
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1714)
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1559)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Unknown Source)
at database.DbConnect.connect(DbConnect.java:20)
at servlets.loginServlet.doPost(loginServlet.java:43)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:647)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:953)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1023)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:310)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)

我正在使用 ojdbc5.jar 它是在 WEB-INF/lib 添加到 bildpath 可能有什么问题？ 使用 PHP，我可以毫无问题地连接到 mySQL 数据库

Answer 1

您正在加载错误的 JDBC 驱动程序。 MySQLs JDBC驱动程序是 com.mysql.jdbc.Driver。您的代码应如下所示:

package database;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;


public class DbConnect {

    /**
     * Static method for user authentication
     * Test method
     * @param username - Username already striped from illigal chars (XSS safe)
     * @param pass - password
     */
    public static void connect(String username,String pass)//Consider changing void to boolean
    {
        Connection con;
        PreparedStatement st;
        ResultSet rs;
        try {
            //Register JDBC driver
            Class.forName("com.mysql.jdbc.Driver");//Loading DB Driver
        } catch (ClassNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

        //Open a connection
        //  Database credentials
        final String USER = "root";
        final String PASS = "";
        final String DB_URL = "jdbc:mysql://localhost:3306/imf_jsp";
        try {
             con = DriverManager.getConnection(DB_URL,USER,PASS);
             st = con.prepareStatement("SELECT * FROM user WHERE signum = ? AND pass_hash = ?"); //Find user with given username & pass
             st.setString(1, username);//Bind param (Should prevent SQL Injection? Not sure but it is working in PHP with PDO)
             st.setString(2, pass);//Bind param (Should prevent SQL Injection? Not sure but it is working in PHP with PDO)
             st.execute();//statemant execution
             System.out.println("In Database?: " + st.toString());//If not then check in LDAP
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        }
    }