java 定时抽取一张表的数据插入到另一张表实现

可以使用 Java 的 Timer 和 TimerTask 类来实现定时任务。

首先，你需要创建一个 Timer 对象，并使用它调度一个 TimerTask 对象，以便在指定的时间间隔内执行任务。在 TimerTask 中，你可以编写代码来抽取一张表的数据并插入到另一张表中。

以下是一个示例代码，可以每隔一分钟从表A中抽取数据并插入到表B中：

import java.sql.*;

public class TableDataTransfer {
    private static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";
    private static final String DB_URL = "jdbc:mysql://localhost:3306/";
    private static final String USER = "root";
    private static final String PASS = "password";
    private static final String SOURCE_TABLE = "table_a";
    private static final String DEST_TABLE = "table_b";

    public static void main(String[] args) {
        Timer timer = new Timer();
        TimerTask task = new TimerTask() {
            @Override
            public void run() {
                Connection conn = null;
                Statement stmt = null;

                try {
                    // Register JDBC driver
                    Class.forName(JDBC_DRIVER);

                    // Open a connection
                    System.out.println("Connecting to database...");
                    conn = DriverManager.getConnection(DB_URL, USER, PASS);

                    // Execute a query to get data from source table
                    System.out.println("Extracting data from source table...");
                    stmt = conn.createStatement();
                    String sql = "SELECT * FROM " + SOURCE_TABLE;
                    ResultSet rs = stmt.executeQuery(sql);

                    // Insert data into destination table
                    System.out.println("Inserting data into destination table...");
                    while (rs.next()) {
                        int id = rs.getInt("id");
                        String name = rs.getString("name");
                        int age = rs.getInt("age");

                        String insertSql = "INSERT INTO " + DEST_TABLE + " (id, name, age) VALUES (" + id + ", '" + name + "', " + age + ")";
                        stmt.executeUpdate(insertSql);
                    }

                    // Clean-up environment
                    rs.close();
                    stmt.close();
                    conn.close();
                } catch (SQLException se) {
                    // Handle errors for JDBC
                    se.printStackTrace();
                } catch (Exception e) {
                    // Handle errors for Class.forName
                    e.printStackTrace();
                } finally {
                    // Finally block used to close resources
                    try {
                        if (stmt != null)
                            stmt.close();
                    } catch (SQLException se2) {
                    } // nothing we can do
                    try {
                        if (conn != null)
                            conn.close();
                    } catch (SQLException se) {
                        se.printStackTrace();
                    } // end finally try
                }
            }
        };
        // Schedule the task to run every minute
        timer.schedule(task, 0, 60 * 1000);
    }
}

请注意，这只是一个基本示例代码，你需要根据实际情况进行修改和优化。例如，你可以添加异常处理、日志记录等功能来提高代码的健壮性。