Question

我有两种完全相同的方法，唯一的区别是在应用程序运行时调用其中一种方法，另一种方法是main(String[] args)方法。

主要方法有效，但只发布控制台信息。

然而，另一种方法应该返回连接对象。相反，我得到了ClassNotFoundException。

工作代码：

public static void main(String[] args) throws ClassNotFoundException, SQLException {

    System.out.println("-------- Oracle JDBC Connection Testing ------");

    try {

        Class.forName("oracle.jdbc.driver.OracleDriver");

    } catch (ClassNotFoundException e) {

        System.out.println("Where is your Oracle JDBC Driver?");
        e.printStackTrace();

        throw e;
    }

    System.out.println("Oracle JDBC Driver Registered!");

    try {

        connection = DriverManager.getConnection(
            "jdbc:oracle:thin:@localhost:1521:xe", "randy",
            "test");

    } catch (SQLException e) {

        System.out.println("Connection Failed! Check output console");
        e.printStackTrace();
        throw e;

    }

    if (connection != null) {
        System.out.println("Happy");
    } else {
        throw new SQLException("Failed to setup the connection");
    }
}

结果：

-------- Oracle JDBC Connection Testing ------
Oracle JDBC Driver Registered!
Happy

但是，如果我将其称为常规方法而不是我的main方法，则会出现错误。这是代码：

错误代码：

public static Connection connect() throws SQLException, ClassNotFoundException {

    if(connection != null){
        return connection;
    }

    System.out.println("-------- Oracle JDBC Connection Testing ------");

    try {

        Class.forName("oracle.jdbc.driver.OracleDriver");

    } catch (ClassNotFoundException e) {

        System.out.println("Where is your Oracle JDBC Driver?");
        e.printStackTrace();
        throw e;
    }

    System.out.println("Oracle JDBC Driver Registered!");

    try {

        connection = DriverManager.getConnection(
            "jdbc:oracle:thin:@localhost:1521:xe", "randy",
            "test");

    } catch (SQLException e) {

        System.out.println("Connection Failed! Check output console");
        e.printStackTrace();
        throw e;

    }

    if (connection != null) {
        return connection;
    } else {
        throw new SQLException("Failed to setup the connection");
    }
}

结果：

-------- Oracle JDBC Connection Testing ------
Where is your Oracle JDBC Driver?
java.lang.ClassNotFoundException: oracle.jdbc.driver.OracleDriver

为什么我会收到该错误？如何解决此问题？

Answer 1

如果从Java EE Web应用程序中调用常规方法connect()，请确保您的oracle驱动程序jar位于web-inf / lib目录中

仅在主方法中不存在时出错：oracle.jdbc.driver.OracleDriver ClassNotFoundException

1 个答案: