java判断mysql为空字符串

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;

public class MySQLExample {
    public static void main(String[] args) {
        String url = "jdbc:mysql://localhost:3306/database_name";
        String user = "username";
        String password = "password";

        try (Connection conn = DriverManager.getConnection(url, user, password);
             Statement stmt = conn.createStatement();
             ResultSet rs = stmt.executeQuery("SELECT column_name FROM table_name WHERE column_name = ''")) {

            while (rs.next()) {
                String value = rs.getString("column_name");
                if (value != null && !value.equals("")) {
                    System.out.println("字段不为空字符串: " + value);
                } else {
                    System.out.println("字段为空字符串或NULL");
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}