11.JDBC的一些工具类

package jdbc;

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


//利用该工具类简化代码
public class Demo_main {
	public static void main(String[] args){
		PreparedStatement ps = null;
		Connection c = null;
		ResultSet rs = null;
			try {
//加载驱动类并建立连接
				c = Demo.getmysqlCon();		
//执行SQL语句					
								
				ps = c.prepareStatement("select * from study where id<? ");
				ps.setObject(1, 10);
				rs = ps.executeQuery();
				while(rs.next()) {
					System.out.println(rs.getInt("id")+"           "+rs.getDate("date")+"          "+rs.getTimestamp("timestamp"));
				}				
			} catch (Exception e) {
				e.printStackTrace();
			}finally {
//关闭
				Demo.closeBase(rs, ps, c);
			}
			
	}

}

工具类

package jdbc;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;

public class Demo {
//加载驱动和获取连接的方法
		public static Connection getmysqlCon() {
			try {
				Class.forName("com.mysql.jdbc.Driver");
				return DriverManager.getConnection("jdbc:mysql://localhost:3306/jdbc的使用","root","root");		
			} catch (Exception e) {
				e.printStackTrace();
				return null;
			}
		}
//常用关闭的方法
		public static void closeBase(ResultSet rs,Statement s, Connection c) {
			try {
				if(s != null) {
					s.close();
					}
			} catch (SQLException e) {
				e.printStackTrace();
			}
			try {
				if(c != null) {
					c.close();
					}
			} catch (SQLException e) {
				e.printStackTrace();
			}
			try {
				if(rs != null) {
					rs.close();						
				}
			} catch (SQLException e) {
				e.printStackTrace();
			}
		}
//时间转字符串
		public static long stringdate(String datestring) {
			DateFormat df = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");
			try {
				return df.parse(datestring).getTime();
			} catch (ParseException e) {
				e.printStackTrace();
				return 0;
			}
		}
}