how to use mysql table's regular expression match spark real time date by java

To use MySQL table's regular expression match Spark real-time date by Java, you can first establish a JDBC connection to the MySQL database from your Java program. Then, you can use Spark's `DataFrame` API and its built-in functions to read data from the MySQL table and apply regular expression matching to the date column. Here's some sample code:

import java.sql.*;
import org.apache.spark.sql.*;

public class MySQLSparkRegexp {
  public static void main(String[] args) {
    // Establish JDBC connection
    String url = "jdbc:mysql://localhost:3306/mydatabase";
    String user = "myuser";
    String password = "mypassword";
    try (Connection conn = DriverManager.getConnection(url, user, password)) {
      // Read data from MySQL table
      String query = "SELECT * FROM mytable";
      DataFrame df = new DataFrameReader(conn)
        .jdbc(url, query, new Properties());

      // Apply regular expression matching to date column
      Column dateCol = df.col("date");
      Column regexpCol = functions.expr("regexp_extract(date, 'myregexp', 0)");
      DataFrame result = df.select(dateCol, regexpCol);

      // Show resulting DataFrame
      result.show();
    } catch (SQLException e) {
      e.printStackTrace();
    }
  }
}

In this sample code, we establish a JDBC connection to a MySQL database and read data from a table called `mytable`. We then apply regular expression matching to the `date` column using Spark's `expr()` function and a regular expression pattern called `myregexp`. Finally, we select the original `date` column and the resulting regular expression column and show the resulting `DataFrame` using Spark's `show()` function.