Java实现基于JDBC操作mysql数据库的方法

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 {
  /**
   * 入口函数
   *
   * @param arg
   */
  public static List<String> queryUserClosed(String today,String lastMonday) {
    List<String> beanList = new ArrayList<String>();
    try {
      Connection con = null; // 定义一个MYSQL链接对象
      Class.forName("com.mysql.jdbc.Driver").newInstance(); // MYSQL驱动
      con = DriverManager.getConnection(
              "jdbc:mysql://localhost:3306/my_db?useUnicode=true&characterEncoding=UTF-8",
              "root", ""); // 链接本地MYSQL
      Statement stmt; // 创建声明
      stmt = con.createStatement();
      // 查询数据并输出
      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()) { // 循环输出结果集
        beanList.add(selectRes.getString("reason"));
      }
    } catch (Exception e) {
      e.printStackTrace();
      System.out.print("MYSQL ERROR:" + e.getMessage());
    }
    return beanList;
  }
}