我试图通过java代码手动连接到oracle数据库，但是我遇到了这个错误。
java代码

public static void main(String[] args) throws Exception {
    //database info
    Class.forName("oracle.jdbc.driver.OracleDriver");
    String url = "jdbc:oracle:thin:@//HOST:1521/SERVICE"
    String username = "*******";
    String password = "*******";
    //Connect
    try{
    Connection conn = DriverManager.getConnection(url, username, password);
    } catch (Exception e){
        System.out.println("convertStackTraceToString(e---------------------------------------");
        System.out.println(convertStackTraceToString(e));
        System.out.println("printStackTrace(e---------------------------------------");
        Thread.sleep(100); // Avoids timing side effect with println and printStackTrace
        e.printStackTrace();
    }

java堆栈跟踪

java.sql.SQLRecoverableException: IO Error: The Network Adapter could not establish the connection
            at oracle.jdbc.driver.T4CConnection.logon(T4CConnection.java:858)
            at oracle.jdbc.driver.PhysicalConnection.connect(PhysicalConnection.java:793)
            at oracle.jdbc.driver.T4CDriverExtension.getConnection(T4CDriverExtension.java:57)
            at oracle.jdbc.driver.OracleDriver.connect(OracleDriver.java:747)
            at oracle.jdbc.driver.OracleDriver.connect(OracleDriver.java:562)
            at java.sql/java.sql.DriverManager.getConnection(DriverManager.java:677)
            at java.sql/java.sql.DriverManager.getConnection(DriverManager.java:228)
            at Main.main(Main.java:33)
            at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
            at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
            at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
            at java.base/java.lang.reflect.Method.invoke(Method.java:566)
            at jdk.compiler/com.sun.tools.javac.launcher.Main.execute(Main.java:404)
            at jdk.compiler/com.sun.tools.javac.launcher.Main.run(Main.java:179)
            at jdk.compiler/com.sun.tools.javac.launcher.Main.main(Main.java:119) 
Caused by: oracle.net.ns.NetException: The Network Adapter could not establish the connection
            at oracle.net.nt.ConnStrategy.execute(ConnStrategy.java:571)
            at oracle.net.resolver.AddrResolution.resolveAndExecute(AddrResolution.java:548)
            at oracle.net.ns.NSProtocol.establishConnection(NSProtocol.java:682)
            at oracle.net.ns.NSProtocol.establishConnection(NSProtocol.java:661)
            at oracle.net.ns.NSProtocolNIO.negotiateConnection(NSProtocolNIO.java:202)
            at oracle.net.ns.NSProtocol.connect(NSProtocol.java:340)
            at oracle.jdbc.driver.T4CConnection.connect(T4CConnection.java:1600)
            at oracle.jdbc.driver.T4CConnection.logon(T4CConnection.java:591)
            ... 14 more 
Caused by: java.io.IOException: Connection refused, socket connect lapse 2 ms. /SCRUB.SCRUB.SCRUB.SCRUB 1521 0 1 true
            at oracle.net.nt.TcpNTAdapter.connect(TcpNTAdapter.java:233)
            at oracle.net.nt.ConnOption.connect(ConnOption.java:174)
            at oracle.net.nt.ConnStrategy.execute(ConnStrategy.java:510)
            ... 21 more 
Caused by: java.net.ConnectException: Connection refused
            at java.base/sun.nio.ch.Net.connect0(Native Method)
            at java.base/sun.nio.ch.Net.connect(Net.java:482)
            at java.base/sun.nio.ch.Net.connect(Net.java:474)
            at java.base/sun.nio.ch.SocketChannelImpl.connect(SocketChannelImpl.java:694)
            at java.base/java.nio.channels.SocketChannel.open(SocketChannel.java:194)
            at oracle.net.nt.TimeoutSocketChannel.connect(TimeoutSocketChannel.java:99)
            at oracle.net.nt.TimeoutSocketChannel.<init>(TimeoutSocketChannel.java:77)
            at oracle.net.nt.TcpNTAdapter.connect(TcpNTAdapter.java:192)
            ... 23 more

我已经检查了凭据和url，它们似乎在另一个系统/网络上工作。我没有访问实际数据库本身的权限，只有要使用的凭据和url。我还可以确认服务器和端口之间的连接。
太好了！