Amazon RDS连接错误

Question

我尝试连接到Amazon RDS并且能够连接一次，但我无法再连接它。我检查了我的用户名，密码，数据库名称，服务器等，它们都是正确的。我在编译之前包含了所有必需的文件。

我在下面附上了我的代码：

import java.io.File;
import java.net.URL;
import java.sql.*;
import java.util.*;

import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;

import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;
import org.xml.sax.InputSource;

import java.net.URL;
import java.sql.*;

import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;

import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;
import org.xml.sax.InputSource;

public class test_url {
   @SuppressWarnings("null")
   public static void main(String[] args){


       String url = "jdbc:mysql://newtes.ctt52jgw7nwb6.eu-west-1.rds.amazonaws.com:3306/";
       String userName = "amankijawani";
       String password = "vegasishere";
       String dbName = "newtesDB";
       String driver = "com.mysql.jdbc.Driver";

       System.out.println("Connecting database...");
       try {
        Class.forName("com.mysql.jdbc.Driver");
        Connection connection = DriverManager.getConnection(url + dbName, userName, password);
        System.out.println("Database connected!");
       } catch (SQLException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (ClassNotFoundException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
}

ERROR

Connecting database...
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(Unknown Source)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
    at java.lang.reflect.Constructor.newInstance(Unknown Source)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:404)
    at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:988)
    at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:341)
    at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2251)
    at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2284)
    at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2083)
    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(Unknown Source)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
    at java.lang.reflect.Constructor.newInstance(Unknown Source)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:404)
    at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:410)
    at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:328)
    at java.sql.DriverManager.getConnection(Unknown Source)
    at java.sql.DriverManager.getConnection(Unknown Source)
    at test_url.main(test_url.java:44)
Caused by: java.net.ConnectException: Connection timed out: connect
    at java.net.DualStackPlainSocketImpl.connect0(Native Method)
    at java.net.DualStackPlainSocketImpl.socketConnect(Unknown Source)
    at java.net.AbstractPlainSocketImpl.doConnect(Unknown Source)
    at java.net.AbstractPlainSocketImpl.connectToAddress(Unknown Source)
    at java.net.AbstractPlainSocketImpl.connect(Unknown Source)
    at java.net.PlainSocketImpl.connect(Unknown Source)
    at java.net.SocksSocketImpl.connect(Unknown Source)
    at java.net.Socket.connect(Unknown Source)
    at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:211)
    at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:300)
    ... 15 more