如何在eclipse中配置javadb？

Question

我尝试了一个关于数据库的简单代码，但它给了我这个错误 -> 错误：没有为 jdbc:derby:CoffeeDB;create=true 找到合适的驱动程序

package Practice;
import java.sql.*;

public class Practice {
public static void main(String[]args)throws Exception{
    final String DB_URL = "jdbc:derby:CoffeeDB;create=true";
    try{
        Connection conn = DriverManager.getConnection(DB_URL);
        Statement stmt = conn.createStatement();

        String sql = ("CREATE TABLE Coffee(Description CHAR(25),Prod Num CHAR(10) NOT NULL PRIMARY KEY,Price DOUBLE)");
        stmt.execute(sql);

        sql = "INSERT INTO Coffee VALUES('Bolivian Dark','14-001',8.95)";
        stmt.executeUpdate(sql);

        sql = "INSERT INTO Coffee VALUES('Bolivian Medium','14-002',8.95)";
        stmt.executeUpdate(sql);

        sql = "INSERT INTO Coffee VALUES('Brazilian Dark','15-001',7.95)";
        stmt.executeUpdate(sql);

        sql = "INSERT INTO Coffee VALUES('Brazilian Medium','15-002',7.95)";
        stmt.executeUpdate(sql);

        sql = "INSERT INTO Coffee VALUES('Brazilian Decaf','15-003',8.55)";
        stmt.executeUpdate(sql);

        sql = "INSERT INTO Coffee VALUES('Central American Dark','16-001',9.95)";
        stmt.executeUpdate(sql);

        sql = "INSERT INTO Coffee VALUES('Central American Medium','16-002',9.95)";
        stmt.executeUpdate(sql);

        sql = "INSERT INTO Coffee VALUES('Sumatra Dark','17-001',7.95)";
        stmt.executeUpdate(sql);

        sql = "INSERT INTO Coffee VALUES('Sumatra Decaf','17-002',8.95)";
        stmt.executeUpdate(sql);

        sql = "INSERT INTO Coffee VALUES('Sumatra Medium','17-003',7.95)";
        stmt.executeUpdate(sql);

        sql = "INSERT INTO Coffee VALUES('Sumatra Organic Dark','17-004',11.95)";
        stmt.executeUpdate(sql);

        sql = "INSERT INTO Coffee VALUES('Kona Medium','18-001',18.45)";
        stmt.executeUpdate(sql);

        sql = "INSERT INTO Coffee VALUES('Kona Dark','18-002',18.45)";
        stmt.executeUpdate(sql);

        sql = "INSERT INTO Coffee VALUES('French Roast Dark','19-001',9.65)";
        stmt.executeUpdate(sql);

        sql = "INSERT INTO Coffee VALUES('Galapagos Medium','20-001',6.85)";
        stmt.executeUpdate(sql);

        sql = "INSERT INTO Coffee VALUES('Guatemalan Dark','21-001',9.95)";
        stmt.executeUpdate(sql);

        sql = "INSERT INTO Coffee VALUES('Guatemalan Decaf','21-002',10.45)";
        stmt.executeUpdate(sql);

        sql = "INSERT INTO Coffee VALUES('Guatemalan Medium','21-003',9.95)";
        stmt.executeUpdate(sql);

        String sqlStatement = "SELECT Description FROM Coffee";
        ResultSet result = stmt.executeQuery(sqlStatement);

        System.out.println("Coffees found in the Database");
        System.out.println("-----------------------------");

        while(result.next()){
            System.out.println(result.getString("Description"));
        }

        conn.close();
    }catch(Exception ex){
        System.out.println("ERROR: " + ex.getMessage());
    }
}
}

谁能给我一个关于如何配置它的逐步过程？我试过寻找答案，但并不彻底。

Answer 1

正如Petter Friberg 所述，您缺少潜水员和驱动程序初始化语句。此外，您需要将 Derby JAR 添加到您的类路径中。

1. 转到Apache Derby 下载并下载库。我试过db-derby-10.11.1.1-lib.zip。
2. 提取存档并将lib/derby.jar 和lib/derbyclient.jar 复制到您的Java 构建路径。
3. 语句"CREATE TABLE Coffee(Description CHAR(25),Prod Num CHAR(10) NOT NULL PRIMARY KEY,Price DOUBLE)" 存在语法错误。您需要删除Prod Num 列名中的空格字符。您可以使用Prod_Num 或ProdNum 或\"Prod Num\"。

Answer 2

1. 下载驱动程序Derby driver，如果我没记错的话是derby.jar（添加到类路径）

2. 连接前注册驱动

   Driver driver =  (Driver) Class.forName("org.apache.derby.jdbc.EmbeddedDriver")
   .newInstance();
   
   DriverManager.registerDriver(driver);
   

您需要尝试 catch 或让您的方法抛出 Class.forName 异常

更多信息请查看SQLException: No suitable driver found for jdbc:derby://localhost:1527