可以帮我用java代码 写一个监听oracle数据库变化的代码吗

当然可以！以下是一个使用Java代码监听Oracle数据库变化的示例：

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import oracle.jdbc.OracleConnection;
import oracle.jdbc.dcn.DatabaseChangeRegistration;
import oracle.jdbc.dcn.DatabaseChangeEvent;
import oracle.jdbc.dcn.DatabaseChangeListener;
import oracle.jdbc.dcn.RowChangeDescription;
import oracle.jdbc.dcn.RowChangeDescription.RowOperation;

public class OracleDBListener {
    private static final String DB_URL = "jdbc:oracle:thin:@localhost:1521:ORCL";
    private static final String DB_USERNAME = "your_username";
    private static final String DB_PASSWORD = "your_password";

    public static void main(String[] args) {
        try {
            // 注册Oracle数据库变化监听器
            OracleConnection connection = registerDatabaseChangeListener();

            // 在连接上执行SQL语句以触发数据库变化事件
            executeSQL(connection);

            // 关闭连接和监听器
            connection.unregisterDatabaseChangeNotification(getDatabaseChangeRegistration());
            connection.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    private static OracleConnection registerDatabaseChangeListener() throws SQLException {
        OracleConnection connection = null;
        try {
            // 创建数据库连接
            connection = (OracleConnection) DriverManager.getConnection(DB_URL, DB_USERNAME, DB_PASSWORD);

            // 创建数据库变化注册
            DatabaseChangeRegistration dcr = connection.registerDatabaseChangeNotification(getDCNProperties());

            // 添加监听器
            DatabaseChangeListener listener = new DatabaseChangeListener() {
                public void onDatabaseChangeNotification(DatabaseChangeEvent e) {
                    if (e.getTableChangeDescription()[0].getRowChangeDescription()[0].getRowOperation() == RowOperation.INSERT) {
                        System.out.println("有新行插入！");
                    } else if (e.getTableChangeDescription()[0].getRowChangeDescription()[0].getRowOperation() == RowOperation.UPDATE) {
                        System.out.println("有行更新！");
                    } else if (e.getTableChangeDescription()[0].getRowChangeDescription()[0].getRowOperation() == RowOperation.DELETE) {
                        System.out.println("有行删除！");
                    }
                }
            };
            dcr.addListener(listener);

            // 开启监听
            connection.setAutoCommit(true);
            return connection;
        } catch (Exception e) {
            if (connection != null) {
                connection.unregisterDatabaseChangeNotification(getDatabaseChangeRegistration());
                connection.close();
            }
            throw e;
        }
    }

    private static void executeSQL(Connection connection) throws SQLException {
        Statement statement = connection.createStatement();
        statement.setDatabaseChangeRegistration(getDatabaseChangeRegistration());
        ResultSet resultSet = statement.executeQuery("SELECT * FROM your_table");
        while (resultSet.next()) {
            // 处理结果集
        }
        statement.close();
    }

    private static Properties getDCNProperties() {
        Properties props = new Properties();
        props.setProperty(OracleConnection.DCN_NOTIFY_ROWIDS, "true");
        props.setProperty(OracleConnection.NTF_LOCAL_HOST, "localhost");
        props.setProperty(OracleConnection.NTF_LOCAL_TCP_PORT, "1521");
        return props;
    }

    private static DatabaseChangeRegistration getDatabaseChangeRegistration() {
        return ((OracleConnection) connection).getDatabaseChangeRegistration();
    }
}

请替换代码中的 `DB_URL`、`DB_USERNAME` 和 `DB_PASSWORD` 为你的实际数据库连接信息，以及将 `your_table` 替换为你要监听的表名。

这段代码使用了 Oracle JDBC 驱动来与 Oracle 数据库建立连接，并使用 `registerDatabaseChangeNotification()` 方法注册数据库变化监听器。在 `onDatabaseChangeNotification()` 方法中可以根据具体的操作类型来处理相应的逻辑。你可以根据实际需求进行修改和扩展。