写一段java线程监控sybase表变更的代码，并将变更字段结果和初始数据用json输出，注意表没有唯一键

由于表没有唯一键，我们无法通过类似于JDBC ResultSet的方式来实现监控Sybase表变更的功能。但是，我们可以通过轮询数据库表，比较前后两次轮询的结果，来判断是否有数据变更。

以下是一个简单的例子，实现了监控Sybase表变更的功能：

import java.sql.*;
import java.util.*;
import com.alibaba.fastjson.*;

public class SybaseTableMonitor implements Runnable {
    private final String url;
    private final String username;
    private final String password;
    private final String tableName;
    private final List<String> columns;
    private final long pollInterval;

    private Map<String, Object> lastRow;

    public SybaseTableMonitor(String url, String username, String password,
                              String tableName, List<String> columns, long pollInterval) {
        this.url = url;
        this.username = username;
        this.password = password;
        this.tableName = tableName;
        this.columns = columns;
        this.pollInterval = pollInterval;
        this.lastRow = null;
    }

    public void run() {
        try {
            Class.forName("com.sybase.jdbc4.jdbc.SybDriver");
            while (true) {
                Map<String, Object> currentRow = queryLastRow();
                if (lastRow != null && !currentRow.equals(lastRow)) {
                    System.out.println("Table " + tableName + " changed:");
                    System.out.println("Before: " + JSON.toJSONString(lastRow));
                    System.out.println("After: " + JSON.toJSONString(currentRow));
                }
                lastRow = currentRow;
                Thread.sleep(pollInterval);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    private Map<String, Object> queryLastRow() throws Exception {
        Connection conn = DriverManager.getConnection(url, username, password);
        Statement stmt = conn.createStatement();
        ResultSet rs = stmt.executeQuery("SELECT TOP 1 " + String.join(",", columns) + " FROM " + tableName + " ORDER BY rowid DESC");
        Map<String, Object> row = new HashMap<>();
        if (rs.next()) {
            for (String column : columns) {
                Object value = rs.getObject(column);
                row.put(column, value);
            }
        }
        rs.close();
        stmt.close();
        conn.close();
        return row;
    }

    public static void main(String[] args) {
        String url = "jdbc:sybase:Tds:localhost:5000/sybase";
        String username = "sa";
        String password = "password";
        String tableName = "my_table";
        List<String> columns = Arrays.asList("column1", "column2", "column3");
        long pollInterval = 1000;

        SybaseTableMonitor monitor = new SybaseTableMonitor(url, username, password, tableName, columns, pollInterval);
        Thread thread = new Thread(monitor);
        thread.start();
    }
}

在这个例子中，我们使用了Sybase的JDBC驱动来连接数据库。在run()方法中，我们不断地轮询数据库表，比较前后两次轮询的结果是否相同。如果有变更，则输出变更前后的JSON数据。

注意，由于表没有唯一键，我们选择了按照rowid排序来查询最新的一行数据。这种方式虽然有一定的局限性，但在很多情况下是可行的。如果您有更好的解决方案，请在评论区留言，谢谢！