package main;import java.sql.Connection;import java.sql.DriverManager;import java.sql.ResultSet;import java.sql.Statement;import java.util.ArrayList;import java.util.List;public class DBConnection {  /**   * 入口函數   *   * @param arg   */  public static List<String> queryUserClosed(String today,String lastMonday) {    List<String> beanList = new ArrayList<String>();    try {      Connection con = null; // 定義一個MYSQL鏈接對象      Class.forName("com.mysql.jdbc.Driver").newInstance(); // MYSQL驅動      con = DriverManager.getConnection(              "jdbc:mysql://localhost:3306/my_db?useUnicode=true&characterEncoding=UTF-8",              "root", ""); // 鏈接本地MYSQL      Statement stmt; // 創建聲明      stmt = con.createStatement();      // 查詢數據并輸出      StringBuffer sql = new StringBuffer();      sql.append(" select reason");      sql.append(" from t1");      sql.append(" GROUP BY reason");      String selectSql = sql.toString();      ResultSet selectRes = stmt.executeQuery(selectSql);      while (selectRes.next()) { // 循環輸出結果集        beanList.add(selectRes.getString("reason"));      }    } catch (Exception e) {      e.printStackTrace();      System.out.print("MYSQL ERROR:" + e.getMessage());    }    return beanList;  }}