java.sql.SQLException : No suitable driver found for jdbc:derby:

Question

我是 jdbc 的初学者...我运行此代码时遇到问题:

此代码使用 appache derby，为了使其工作，我首先启动了 derby 服务器..

      java -jar "C:\Program Files\Sun\JavaDB\lib\derbyrun.jar" server start

然后启动程序

      java -classpath derbyclient.jar -jar TestDB.jar

我设置了类路径 C:\Program Files\Sun\JavaDB\lib\derby.jar

我总是遇到这种异常

java.sql.SQLException:找不到适用于 jdbc:derby://localhost:1527/的驱动程序BOOKDB;创建=真 在 java.sql.DriverManager.getConnection(DriverManager.java:602) 在 java.sql.DriverManager.getConnection(DriverManager.java:185) 在 TestDB.getConnection(TestDB.java:63) 在 TestDB.runTest(TestDB.java:20) 在 TestDB.main(TestDB.java:11)

import java.sql.*;
import java.io.*;
import java.util.*;


class TestDB
{
   public static void main(String args[])
   {
      try
      {
         runTest();
      }
      catch (SQLException ex)
      {
         for (Throwable t : ex)
            t.printStackTrace();
      }
      catch (IOException ex)
      {
         ex.printStackTrace();
      }
   }

   public static void runTest() throws SQLException, IOException
   {
      Connection conn = getConnection();
      try
      {
         Statement stat = conn.createStatement();

         stat.executeUpdate("CREATE TABLE Greetings (Message CHAR(20))");
         stat.executeUpdate("INSERT INTO Greetings VALUES ('Hello, World!')");

         ResultSet result = stat.executeQuery("SELECT * FROM Greetings");
         if (result.next())
            System.out.println(result.getString(1));
         result.close();
         stat.executeUpdate("DROP TABLE Greetings");
      }
      finally
      {
         conn.close();
      }
   }

   public static Connection getConnection() throws SQLException, IOException
   {
      Properties props = new Properties();
      FileInputStream in = new FileInputStream("database.properties");
      props.load(in);
      in.close();

      String drivers = props.getProperty("jdbc.drivers");
      if (drivers != null) System.setProperty("jdbc.drivers", drivers);
      String url = props.getProperty("jdbc.url");
      String username = props.getProperty("jdbc.username");
      String password = props.getProperty("jdbc.password");

      return DriverManager.getConnection(url, username, password);
   }
}

Answer 1

当您使用 -jar 和 -classpath 参数调用 java 命令时，-classpath 参数被忽略。请参阅documentation for the Java launcher .

您可以使用:

Unix/Linux:

java -classpath derbyclient.jar:TestDB.jar TestDB

Windows:

java -classpath derbyclient.jar;TestDB.jar TestDB

或者制作一个 list ，将 derbyclient.jar 添加到类路径中。