软工第五周：安卓连接MySql

package com.example.myapplication;
import android.util.Log;

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

import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

/**
 * 数据库工具类：连接数据库用、获取数据库数据用
 * 相关操作数据库的方法均可写在该类
 */
public class db {

    private static String driver = "com.mysql.jdbc.Driver";
         // MySql驱动

//    private static String url = "jdbc:mysql://localhost:3306/map_designer_test_db";

    private static String user = "root";// 用户名

    private static String password = "zhangziyi1670";// 密码

    private static Connection getConn(String dbName) {

        Connection connection = null;
        try {
            Class.forName(driver);// 动态加载类
            String ip = "192.168.1.7";// 写成本机地址，不能写成localhost，同时手机和电脑连接的网络必须是同一个

            // 尝试建立到给定数据库URL的连接
            connection = DriverManager.getConnection("jdbc:mysql://" + ip + ":3306/" + dbName,
                    user, password + "&useSSL=false&serverTimezone=UTC&useSSL=false&serverTimezone=UTC");

        } catch (Exception e) {
            e.printStackTrace();
        }

        return connection;
    }
    public static List<CostBean> search(String time,String area){
       List<CostBean>list=new ArrayList<CostBean>();
        Connection connection = getConn("pachong");

        try {
            // mysql简单的查询语句。这里是根据MD_CHARGER表的NAME字段来查询某条记录
            String sql = "select * from todaydata_copy1 where updateDate = ? and provinceid = ? ";
//            String sql = "select * from MD_CHARGER";
            if (connection != null){// connection不为null表示与数据库建立了连接
                PreparedStatement ps = connection.prepareStatement(sql);
                if (ps != null){
                    // 设置上面的sql语句中的？的值为name
                    ps.setString(1, time);
                    ps.setString(2,area);
                    // 执行sql查询语句并返回结果集
                    ResultSet rs = ps.executeQuery();
                    if (rs != null){
                        int count = rs.getMetaData().getColumnCount();
                        Log.e("DBUtils","列总数：" + count);
                        while (rs.next()){
                            // 注意：下标是从1开始的
                            for (int i = 1;i <= count;i++){
                               String time1=rs.getString("updateData");
                               String area1=rs.getString("provinceid");
                               String conformednum=rs.getString("confirmedNum");
                               CostBean costBean=new CostBean(time1,area1,conformednum);
                               list.add(costBean);
                            }
                        }
                        connection.close();
                        ps.close();
                        return  list;
                    }else {

                        return null;
                    }
                }else {
                    return  null;
                }
            }else {
                Log.e("message","con未连接成功");
                return  null;
            }
        }catch (SQLException e){
            e.printStackTrace();
            Log.e("DBUtils","异常：" + e.getMessage());
            return null;
        }
    }
}