如何用JDBC连接到Oracle数据库[副本]

Question

package net.codejava;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;

public class JavaOracleTest {

    public static void main(String[] args) {
        String dbURL = "jdbc:oracle:thin:@localhost:1521:xe";
        String username = "msbd**";
        String password = "haslo****";
        
        try {
            Connection connection = DriverManager.getConnection(dbURL, username, password);
            System.out.println("Połączono z serwerem Oracle");
        } catch (SQLException e) {
            System.out.println("Error");
            e.printStackTrace();
        }

    }

}

这是我得到的错误：

java.sql.SQLRecoverableException: IO Error: The Network Adapter could not establish the connection (CONNECTION_ID=yV+3U5v4TK2js7gMFTixxA==)
Error
    at oracle.jdbc.driver.T4CConnection.handleLogonNetException(T4CConnection.java:882)
    at oracle.jdbc.driver.T4CConnection.logon(T4CConnection.java:687)
    at oracle.jdbc.driver.PhysicalConnection.connect(PhysicalConnection.java:1086)
    at oracle.jdbc.driver.T4CDriverExtension.getConnection(T4CDriverExtension.java:90)
    at oracle.jdbc.driver.OracleDriver.connect(OracleDriver.java:728)
    at oracle.jdbc.driver.OracleDriver.connect(OracleDriver.java:649)
    at java.sql/java.sql.DriverManager.getConnection(DriverManager.java:677)
    at java.sql/java.sql.DriverManager.getConnection(DriverManager.java:228)
    at net.codejava.JavaOracleTest.main(JavaOracleTest.java:15)
Caused by: oracle.net.ns.NetException: The Network Adapter could not establish the connection (CONNECTION_ID=yV+3U5v4TK2js7gMFTixxA==)
    at oracle.net.nt.ConnStrategy.execute(ConnStrategy.java:677)
    at oracle.net.resolver.AddrResolution.resolveAndExecute(AddrResolution.java:568)
    at oracle.net.ns.NSProtocol.establishConnection(NSProtocol.java:953)
    at oracle.net.ns.NSProtocol.connect(NSProtocol.java:350)
    at oracle.jdbc.driver.T4CConnection.connect(T4CConnection.java:2155)
    at oracle.jdbc.driver.T4CConnection.logon(T4CConnection.java:652)
    ... 7 more
Caused by: java.io.IOException: Connection refused: connect, socket connect lapse 2003 ms. localhost 1521  0 (2/2) true
    at oracle.net.nt.TcpNTAdapter.establishSocket(TcpNTAdapter.java:421)
    at oracle.net.nt.TcpNTAdapter.doLocalDNSLookupConnect(TcpNTAdapter.java:303)
    at oracle.net.nt.TcpNTAdapter.connect(TcpNTAdapter.java:265)
    at oracle.net.nt.ConnOption.connect(ConnOption.java:238)
    at oracle.net.nt.ConnStrategy.executeConnOption(ConnStrategy.java:902)
    at oracle.net.nt.ConnStrategy.execute(ConnStrategy.java:638)
    ... 12 more
Caused by: java.net.ConnectException: Connection refused: connect
    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:184)
    at oracle.net.nt.TimeoutSocketChannel.<init>(TimeoutSocketChannel.java:158)
    at oracle.net.nt.TcpNTAdapter.establishSocket(TcpNTAdapter.java:380)
    ... 17 more

我用*替换了一些细节，因为这是学校的数据库。

Answer 1

您的错误是：

Caused by: java.net.ConnectException: Connection refused: connect

检查您是否有：

>

正确的主机名。

String dbURL = "jdbc:oracle:thin:@localhost:1521:xe";

String dbURL = "jdbc:oracle:thin:@155.158.xxx.xx:1521:xe";

例如，是否应该：

String dbURL = "jdbc:oracle:thin:@155.158.xxx.xx:1521:olt*****";

正确的用户名和密码。

对数据库的访问。