java - 在 Java 中连接到 Oracle DB 返回 NullPointerException

Question

我有这个方法来连接到oracle 11g xe。它仍然返回异常 java.lang.NullPointerException。我使用 Eclipse IDE。请帮忙，我不知道如何解决它。

public static Connection connectDB() throws ClassNotFoundException, SQLException, InstantiationException, IllegalAccessException {

    Connection connection = null;
    try {
        // Load the JDBC driver
        String driverName = "oracle.jdbc.driver.OracleDriver";
        Class.forName(driverName).newInstance();

        // Create a connection to the database
        String serverName = "127.0.0.1";
        String portNumber = "1521";
        String sid = "xe";
        String url = "jdbc:oracle:thin:@" + serverName + ":" + portNumber + ":" + sid;
        String username = "peter";
        String password = "pass";
        connection = DriverManager.getConnection(url, username, password);
        System.out.println(connection);
    } catch (ClassNotFoundException e) {
        // Could not find the database driver
    } catch (SQLException e) {
        // Could not connect to the database
    }
    System.out.println(connection);
    return connection;
}

Answer 1

问题出在 Oracle 驱动程序中。我通过将我需要的 ojdbc14.jar 文件放入服务器文件夹来解决这个问题。我使用的是 tomcat，所以我将 ojdbc14.jar 文件放入文件夹 apache-tomcat-7.0.8\lib\