java - 无法从 JavaFX 应用程序连接到远程 MySQL 数据库

Question

我创建了一个应用程序，它与我笔记本电脑上的远程 MySQL 数据库进行通信。当我使用本地主机进行连接时，该应用程序工作正常:

public class DbConncetion {
   public Connection Connect(){
        try {
            Class.forName("com.mysql.jdbc.Driver");
            Connection con= DriverManager.getConnection("jdbc:mysql://localhost:3306/cms?autoReconnect=true&useSSL=false","root","");
            return con;
        }
        catch(Exception ex){
            System.out.println(ex);       
        }
        return null;
       }

}

效果非常好。但是当我使用我的公共(public) IP 地址而不是“localhost”时，应用程序会抛出:

com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Could not create connection to database server. Attempted reconnect 3 times. Giving up.
java.lang.NullPointerException

我在这个论坛里查了很多，但没有找到任何东西。我创建用户并授予他 XAMPP MySQL 中的所有权限，如下所示:

This is pic from there

我配置了路由器，但不确定它是否正确: This is pic from there谁能告诉我，我哪里出错了？预先感谢:)

这是完整的堆栈跟踪:t

com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2088)
    at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:806)
    at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:425)
    at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:410)
    at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:328)
    at java.sql.DriverManager.getConnection(DriverManager.java:664)
    at java.sql.DriverManager.getConnection(DriverManager.java:247)
    at DBconnection.DbConncetion.Connect(DbConncetion.java:24)
    at javafxapplication1.Main1Controller.loadData(Main1Controller.java:208)
    at javafxapplication1.Main1Controller.lambda$new$0(Main1Controller.java:232)
    at com.sun.scenario.animation.shared.TimelineClipCore.visitKeyFrame(TimelineClipCore.java:239)
    at com.sun.scenario.animation.shared.TimelineClipCore.playTo(TimelineClipCore.java:180)
    at javafx.animation.Timeline.impl_playTo(Timeline.java:176)
    at javafx.animation.AnimationAccessorImpl.playTo(AnimationAccessorImpl.java:39)
    at com.sun.scenario.animation.shared.InfiniteClipEnvelope.timePulse(InfiniteClipEnvelope.java:110)
    at javafx.animation.Animation.impl_timePulse(Animation.java:1102)
    at javafx.animation.Animation$1.lambda$timePulse$25(Animation.java:186)
    at java.security.AccessController.doPrivileged(Native Method)
    at javafx.animation.Animation$1.timePulse(Animation.java:185)
    at com.sun.scenario.animation.AbstractMasterTimer.timePulseImpl(AbstractMasterTimer.java:344)
    at com.sun.scenario.animation.AbstractMasterTimer$MainLoop.run(AbstractMasterTimer.java:267)
    at com.sun.javafx.tk.quantum.QuantumToolkit.pulse(QuantumToolkit.java:506)
    at com.sun.javafx.tk.quantum.QuantumToolkit.pulse(QuantumToolkit.java:490)
    at com.sun.javafx.tk.quantum.QuantumToolkit.lambda$runToolkit$404(QuantumToolkit.java:319)
    at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
    at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
    at com.sun.glass.ui.win.WinApplication.lambda$null$148(WinApplication.java:191)
    at java.lang.Thread.run(Thread.java:745)
Caused by: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:425)
    at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:989)
    at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:341)
    at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2251)
    at com.mysql.jdbc.ConnectionImpl.connectWithRetries(ConnectionImpl.java:2104)
    ... 33 more
Caused by: java.net.ConnectException: Connection refused: connect
    at java.net.TwoStacksPlainSocketImpl.socketConnect(Native Method)
    at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350)
    at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
    at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
    at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172)
    at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
    at java.net.Socket.connect(Socket.java:589)
    at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:211)
    at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:300)
    ... 35 more

Feb 18, 2017 2:23:03 PM DBconnection.DbConncetion Connect
SEVERE: null
com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Could not create connection to database server. Attempted reconnect 3 times. Giving up.
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:425)
    at com.mysql.jdbc.Util.getInstance(Util.java:408)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:918)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:897)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:886)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:860)
    at com.mysql.jdbc.ConnectionImpl.connectWithRetries(ConnectionImpl.java:2163)

Answer 1

您必须在Mysql用户配置中允许应用程序ip地址，在您的图片中您已经屏蔽了允许的ip，该ip必须是应用程序服务器ip。

如果您从数据库主机的同一本地网络运行 Web 应用程序，则无法连接到数据库主机的公共(public) IP，路由器也无法简单地执行此操作。

因此，对于本地测试，您必须使用 localhost。

当您部署应用程序时，您必须使用 public。

顺便说一句，将 mysql 数据库端口公开到互联网并不是一个好的做法。