连接到Derby网络服务器时出现数据库未找到错误

Question

我在初始化javadb网络服务器并设置与它的连接时遇到问题。这是一个JavaFX程序。

这就是我目前所拥有的：

try {
        Class.forName("org.apache.derby.jdbc.ClientDriver").newInstance();
        javadbserver = new NetworkServerControl();
        javadbserver.start(null);
    } catch (ClassNotFoundException e) {
        Logger.getLogger(MainGuiController.class.getName()).log(Level.SEVERE, null, ex);
        System.out.println("Where is your JavaDB embedded Driver?");
        return;
    }
    String dbName = "mydb";
    String dbUser = "auser";
    String dbPass = "password";
    PreparedStatement prepstmt;
    try {
        this.conn = DriverManager.getConnection("jdbc:derby://localhost:1527/mydb;user=auser;password=password");
        System.out.println("Went through!");
    } catch (SQLException ex) {
        Logger.getLogger(MainGuiController.class.getName()).log(Level.SEVERE, null, ex);
    }

我总是抓住第二个例外。

如果我右键单击netbeans中的javadb服务并选择connect，那么一切都会顺利运行。[事实上，当我选择时，如果能知道java在后台运行什么代码或程序，那就太好了]

在库下的项目列表中，我看到了derby.jar、derbyclient.jar和derbynet.jar

我做错了什么？请帮忙！

这是我得到的错误

java.sql.SQLNonTransientConnectionException: The connection was refused because the database mydb was not found.
    at org.apache.derby.client.am.SQLExceptionFactory40.getSQLException(Unknown Source)
    at org.apache.derby.client.am.SqlException.getSQLException(Unknown Source)
    at org.apache.derby.jdbc.ClientDriver.connect(Unknown Source)
    at java.sql.DriverManager.getConnection(DriverManager.java:579)
    at java.sql.DriverManager.getConnection(DriverManager.java:243)
    at mydb.MainGuiController.initialize(MainGuiController.java:105)
    at javafx.fxml.FXMLLoader.load(FXMLLoader.java:2152)
    at javafx.fxml.FXMLLoader.load(FXMLLoader.java:2028)
    at mydb.mydb.start(mydb.java:37)
    at com.sun.javafx.application.LauncherImpl$5.run(LauncherImpl.java:319)
    at com.sun.javafx.application.PlatformImpl$5.run(PlatformImpl.java:215)
    at com.sun.javafx.application.PlatformImpl$4$1.run(PlatformImpl.java:179)
    at com.sun.javafx.application.PlatformImpl$4$1.run(PlatformImpl.java:176)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.javafx.application.PlatformImpl$4.run(PlatformImpl.java:176)
    at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
    at com.sun.glass.ui.win.WinApplication.access$100(WinApplication.java:29)
    at com.sun.glass.ui.win.WinApplication$3$1.run(WinApplication.java:73)
    at java.lang.Thread.run(Thread.java:722)
Caused by: org.apache.derby.client.am.DisconnectException: The connection was refused because the database mydb was not found.
    at org.apache.derby.client.net.NetConnectionReply.parseRDBNFNRM(Unknown Source)
    at org.apache.derby.client.net.NetConnectionReply.parseAccessRdbError(Unknown Source)
    at org.apache.derby.client.net.NetConnectionReply.parseACCRDBreply(Unknown Source)
    at org.apache.derby.client.net.NetConnectionReply.readAccessDatabase(Unknown Source)
    at org.apache.derby.client.net.NetConnection.readSecurityCheckAndAccessRdb(Unknown Source)
    at org.apache.derby.client.net.NetConnection.flowSecurityCheckAndAccessRdb(Unknown Source)
    at org.apache.derby.client.net.NetConnection.flowUSRIDPWDconnect(Unknown Source)
    at org.apache.derby.client.net.NetConnection.flowConnect(Unknown Source)
    at org.apache.derby.client.net.NetConnection.<init>(Unknown Source)
    at org.apache.derby.client.net.NetConnection40.<init>(Unknown Source)
    at org.apache.derby.client.net.ClientJDBCObjectFactoryImpl40.newNetConnection(Unknown Source)

Answer 1

根据JDBC url，看起来您正试图连接到Derby服务器，而不是嵌入式实例。如果您试图连接到服务器实例，以下是一些注意事项：

• 你自己启动服务器了吗？mydb已经存在了吗
• 如果没有，您是否传入了要创建的正确参数（例如；create=true）example: jdbc:derby://localhost:1527/dbname;create=true
• 如果mydb确实存在，您是否将服务器指向正确的位置？
  • 此外，根据用于启动derby的内容（例如嵌入式与网络驱动程序），默认数据库位置也有所不同。你可以在这里阅读

基本上，你得到的例外是Derby说它找不到你的数据库——这基本上是一个路径问题。

Answer 2

如果您使用的是netbeans，您应该通过进入连接属性并添加一个属性来解决这个问题。在"property"下键入"create"，在"value"下输入"true"。