JAVA------8.连接mysql数据库

 1 package com.caipei.thread;
 2 
 3 import java.io.BufferedReader;
 4 import java.io.IOException;
 5 import java.io.InputStreamReader;
 6 import java.io.OutputStreamWriter;
 7 import java.io.Writer;
 8 import java.net.ServerSocket;
 9 import java.net.Socket;
10 import java.sql.Connection;
11 import java.sql.DriverManager;
12 import java.sql.ResultSet;
13 import java.sql.SQLException;
14 import java.sql.Statement;
15 import java.text.SimpleDateFormat;
16 import java.util.Calendar;
17 import java.util.Random;
18 
19 public class ServerDemo {
20     //crc 校验
21     private static CrcUtil demo;
22     //str 转字节
23     private static StringToByteutil strToByte;
24     private static  Connection conn = null;
25     private SimpleDateFormat formatter = new SimpleDateFormat(
26             "yyyy-MM-dd HH:mm:ss");
27     static String driver = "com.mysql.jdbc.Driver";
28     // URL指向要访问的数据库名******
29     //static String url = "jdbc:mysql://:3306/hhxficdz_schema";
30     static String url = "jdbc:mysql://localhost:3306/hhxficdz_schema";
31     // MySQL配置时的用户名
32     static String user = "";
33     // Java连接MySQL配置时的密码******
34     //static String password = "";
35     static String password = "123456";
36     //crc校验
37     private static CrcUtil crc;
38     private static  Connection getconn() {
39         //驱动程序名//不固定，根据驱动
40         try {
41             Class.forName(driver);
42             conn = DriverManager.getConnection(url, user, password);
43         } catch (SQLException e) {
44             // TODO Auto-generated catch block
45             e.printStackTrace();
46         } catch (ClassNotFoundException e) {
47             // TODO Auto-generated catch block
48             e.printStackTrace();
49         }
50         // System.out.println(props.getProperty("mysql.connection.driver_class"));
51         return conn;
52     }

处理数据库

 1 ResultSet rs = null;
 2                 Statement stmt = null;
 3                 String state=null;
 4                 String eqid=null;
 5                 String returnNun=null;
 6                 conn = getconn();
 7                 stmt = conn.createStatement();
 8 
 9                 // 01：查询充电桩状态
10                 if (taskNum.equals("01")) 
11                 {
12                     try {
13                         // 要执行的SQL语句eqnum中的项。
14                         String sql = " select * from t_eqregister where eqnum='"+ choNum + "'";
15                         rs = stmt.executeQuery(sql);  
16                         //输出id值和content值
17                         while(rs.next()) {
18                             flag=0;
19                             //充电桩状态
20                             state = rs.getString("state");
21                             //如果充电桩状态是 3 将充电桩状态 置0
22                             if (Integer.valueOf(state)==3) {
23                                 //修改充电桩注册表的状态为1 
24                                 String eqsql = " update t_eqregister t set t.state=0 where t.eqnum='"+choNum+"'";
25                                 stmt.execute(eqsql);
26                             }
27 
28                             //校验码之前字符串
29                             String leftstr="FF"+"00"+sb.substring(4,12)+"0"+state;
30                             int le=leftstr.length()/2;
31                             //校验码计算
32                             String yanNum=String.valueOf(Integer.toHexString(demo.CRC16(strToByte.stringToByte(leftstr),le))).toUpperCase();
33                             returnNun=leftstr+yanNum;
34 
35                         } 
36                         rs.close(); 
37                         conn.close();  
38                     }  catch (SQLException e) {
39                         // TODO Auto-generated catch block
40                         e.printStackTrace();
41                     } 
42                 }