本文主要写了如何测试连接mysql数据库,sql操作数据库以及读出来的数据逐行处理,如有错误,请不吝赐教。
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;
import redis.clients.jedis.JedisCluster;
/**
* define mysql handlers
*
* @author dmvoishi
* @since 20181024
*/
public class MysqlUtil {
static JedisCluster jedisCluster = RedisUtil.getJedisCluster();
public static void main(String[] args) {
String mysqlConfigPath = "hdfs:///user/hdfs/mysql.cfg";
// 声明Connection对象
Connection con;
Properties prop = CommonUtils.getProperty(mysqlConfigPath, "hdfs");
// 驱动程序名
// String driver = "com.mysql.jdbc.Driver";
String driver = prop.getProperty("driver");
// URL指向要访问的数据库名mydata
// String url = "jdbc:mysql://10.0.0.1:3306/";
String url = prop.getProperty("url");
// MySQL配置时的用户名
// String user = "root";
String user = prop.getProperty("user");
// MySQL配置时的密码
// String password = "root";
String password = prop.getProperty("password");
// 遍历查询结果集
try {
// 加载驱动程序
Class.forName(driver);
// 1.getConnection()方法,连接MySQL数据库!!
con = DriverManager.getConnection(url, user, password);
if (!con.isClosed())
System.out.println("Succeeded connecting to the Database!");
// 2.创建statement类对象,用来执行SQL语句!!
Statement statement = con.createStatement();
// 要执行的SQL语句
// String sql = "select plc_name,plc_data_name,id from alarm";
String sql = "select CONCAT(plc_name,\"_alarm\") plc_name,CONCAT(\"{\",GROUP_CONCAT(CONCAT(\"\"\"\",plc_data_name,\"\"\"\",\":\",\"\"\"\",id,\"\"\"\")),\"}\") alarm_content from alarm GROUP BY plc_name";
// 3.ResultSet类,用来存放获取的结果集!!
// statement.executeQuery(sql);
ResultSet rs = statement.executeQuery(sql);
String plc_name = "plc_name";
String alarm_content = "alarm_content";
while (rs.next()) {
plc_name = rs.getString("plc_name");
alarm_content = rs.getString("alarm_content");
jedisCluster.set(plc_name, alarm_content);
// System.out.println(plc_name);
// System.out.println(alarm_content);
}
rs.close();
con.close();
} catch (ClassNotFoundException e) {
// 数据库驱动类异常处理
System.out.println("Sorry,can`t find the Driver!");
e.printStackTrace();
} catch (SQLException e) {
// 数据库连接失败异常处理
e.printStackTrace();
} catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
} finally {
System.out.println("数据库数据成功获取!!");
}
}
}