java - H2 数据库用户定义的 java 函数类未找到

Question

当我创建一个用于在 H2 数据库中注册 java 函数的别名时，它给出了找不到类的错误。我在 tcp 连接上运行 h2 数据库。

示例，

public class TimeFrame { 
    public static void main(String... args) throws Exception {
        Class.forName("org.h2.Driver");
        Connection conn = DriverManager.getConnection("jdbc:h2:tcp://MYIP:9092/~/test", "sa", "");
        Statement stat = conn.createStatement();

        //Setup Table
        stat.execute("DROP TABLE IF EXISTS timeframe");
        stat.execute("CREATE TABLE timeframe (last_updated TIMESTAMP, ip int");
        stat.execute("CREATE ALIAS IF NOT EXISTS SLIDEWINDOW FOR \"h2TimeFrame.TimeFrame.slidewindow\" ");
    }
}

这一切都在包名中:h2TimeFrame。测试，

从 org.h2.samples 包中获取示例类“Function”。您将如何在具有 TCP 连接的服务器上运行此类。改变

  Connection conn = DriverManager.getConnection("jdbc:h2:~/test", "sa", "");

到

  Connection conn = DriverManager.getConnection("jdbc:h2:tcp://IPADDRESS:9092/~/test", "sa", "");

Answer 1

确保:

• 类是public
• 该方法是public 和static

• 该类必须在数据库引擎的类路径中可用

  来自 H2 Docs :

  When referencing a method, the class must already be compiled and included in the classpath where the database is running. Only static Java methods are supported; both the class and the method must be public