写一段java监控sybase数据表变更的代码并用线程获取变更信息
时间: 2023-05-31 17:07:05 浏览: 60
由于Sybase数据库没有类似Oracle的触发器(Trigger)可以直接监控表变更,因此需要通过轮询的方式来检查表变更。以下是一个简单的Java代码示例,用于监控Sybase数据库中指定表的变更情况并将变更信息输出到控制台:
```
import java.sql.*;
import java.util.*;
import java.lang.*;
public class SybaseTableMonitor implements Runnable {
private Connection conn;
private String tableName;
private Map<String, Integer> columnValues;
public SybaseTableMonitor(Connection conn, String tableName) {
this.conn = conn;
this.tableName = tableName;
this.columnValues = new HashMap<String, Integer>();
}
public void run() {
try {
Statement stmt = conn.createStatement();
ResultSet rs = null;
while (true) {
// Query the table for changes
rs = stmt.executeQuery("SELECT * FROM " + tableName);
ResultSetMetaData rsmd = rs.getMetaData();
int numColumns = rsmd.getColumnCount();
Map<String, Integer> newColumnValues = new HashMap<String, Integer>();
// Check if any column values have changed
while (rs.next()) {
for (int i = 1; i <= numColumns; i++) {
String columnName = rsmd.getColumnName(i);
int columnValue = rs.getInt(columnName);
// Compare with previous column value
if (columnValues.containsKey(columnName)) {
int prevValue = columnValues.get(columnName);
if (prevValue != columnValue) {
System.out.println("Table " + tableName + ": " + columnName + " changed from " + prevValue + " to " + columnValue);
}
}
// Store the new column value
newColumnValues.put(columnName, columnValue);
}
}
// Update the previous column values
columnValues = newColumnValues;
// Wait for 1 second before checking again
Thread.sleep(1000);
}
} catch (SQLException e) {
e.printStackTrace();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
public static void main(String[] args) throws SQLException {
// Connect to Sybase database
String url = "jdbc:sybase:Tds:host:port/database";
String user = "username";
String password = "password";
Connection conn = DriverManager.getConnection(url, user, password);
// Start a new thread to monitor table changes
SybaseTableMonitor monitor = new SybaseTableMonitor(conn, "mytable");
Thread thread = new Thread(monitor);
thread.start();
}
}
```
在上面的代码中,我们创建了一个名为SybaseTableMonitor的类,它实现了Runnable接口,可以在一个单独的线程中运行。构造函数需要传入一个Connection对象和表名。在run()方法中,我们使用Statement对象执行一个SELECT语句来查询指定表的数据。然后,我们比较当前的列值与上一次的列值,如果发现有变更,则将变更信息输出到控制台。最后,我们使用Thread.sleep()方法暂停1秒钟,然后重新查询表数据,以便继续监控变更情况。
在main()方法中,我们首先连接到Sybase数据库,然后创建一个SybaseTableMonitor对象并在一个新线程中运行它。这样,我们就可以在后台监控指定表的变更情况。