JAVA------8.连接mysql数据库

package com.caipei.thread;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.Writer;
import java.net.ServerSocket;
import java.net.Socket;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Random;

public class ServerDemo {
    //crc 校验
    private static CrcUtil demo;
    //str 转字节
    private static StringToByteutil strToByte;
    private static  Connection conn = null;
    private SimpleDateFormat formatter = new SimpleDateFormat(
            "yyyy-MM-dd HH:mm:ss");
    static String driver = "com.mysql.jdbc.Driver";
    // URL指向要访问的数据库名******
    //static String url = "jdbc:mysql://:3306/hhxficdz_schema";
    static String url = "jdbc:mysql://localhost:3306/hhxficdz_schema";
    // MySQL配置时的用户名
    static String user = "";
    // Java连接MySQL配置时的密码******
    //static String password = "";
    static String password = "123456";
    //crc校验
    private static CrcUtil crc;
    private static  Connection getconn() {
        //驱动程序名//不固定，根据驱动
        try {
            Class.forName(driver);
            conn = DriverManager.getConnection(url, user, password);
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (ClassNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        // System.out.println(props.getProperty("mysql.connection.driver_class"));
        return conn;
    }

处理数据库

ResultSet rs = null;
                Statement stmt = null;
                String state=null;
                String eqid=null;
                String returnNun=null;
                conn = getconn();
                stmt = conn.createStatement();

                // 01：查询充电桩状态
                if (taskNum.equals("01")) 
                {
                    try {
                        // 要执行的SQL语句eqnum中的项。
                        String sql = " select * from t_eqregister where eqnum='"+ choNum + "'";
                        rs = stmt.executeQuery(sql);  
                        //输出id值和content值
                        while(rs.next()) {
                            flag=0;
                            //充电桩状态
                            state = rs.getString("state");
                            //如果充电桩状态是 3 将充电桩状态 置0
                            if (Integer.valueOf(state)==3) {
                                //修改充电桩注册表的状态为1 
                                String eqsql = " update t_eqregister t set t.state=0 where t.eqnum='"+choNum+"'";
                                stmt.execute(eqsql);
                            }

                            //校验码之前字符串
                            String leftstr="FF"+"00"+sb.substring(4,12)+"0"+state;
                            int le=leftstr.length()/2;
                            //校验码计算
                            String yanNum=String.valueOf(Integer.toHexString(demo.CRC16(strToByte.stringToByte(leftstr),le))).toUpperCase();
                            returnNun=leftstr+yanNum;

                        } 
                        rs.close(); 
                        conn.close();  
                    }  catch (SQLException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    } 
                }