MySQL 数据库连接 静态语句块

package cn.sjy.org.dbconn;

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

import cn.sjy.org.exception.*;

public class MysqlDBConn {
		private static final String DBDRIVER = "com.mysql.jdbc.Driver";
		private static final String DBURL = "jdbc:mysql://127.0.0.1:3306/book";
		private static final String DBUSER = "root";
		private static final String DBPASSWORD = "root";
		private static MysqlDBConn mysqldbconn = null; 
		Connection conn = null;
		static{
			try {
				Class.forName(DBDRIVER);
			} catch (ClassNotFoundException e) {
				e.printStackTrace();
				throw new MyRunTimeException("驱动加载失败", e);
			}
		}
		
		public static MysqlDBConn getMysqlDBConn(){
			if(mysqldbconn == null){mysqldbconn = new MysqlDBConn();}
			return mysqldbconn;
		}
		
		public  Connection getconnection(){
			try {
				conn = DriverManager.getConnection(this.DBURL, this.DBUSER, this.DBPASSWORD);
			} catch (SQLException e) {
				e.printStackTrace();
				throw new MyRunTimeException("连接数据库失败", e);
			}
			return conn;
		}
		
}