连接到数据库

连接到数据库（非Data Source）

消愁 - 毛不易

试代码如下

package database;

import java.io.FileInputStream;
import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Properties;

public class TestDB {
	public static void main(String[] args) {
		ResultSet rs=null;
		PreparedStatement pstmt=null;
		try{
			String sql="select ename from emp where empno=?";
			Connection conn=getConnection();
			pstmt=conn.prepareStatement(sql);
			pstmt.setInt(1, 1002);
			rs=pstmt.executeQuery();
			while(rs.next()){
				System.out.println(rs.getString("ename"));
			}
			rs.close();
			pstmt.close();
			
		}catch(Exception e){
			e.printStackTrace();
		}finally{
			
		}
	}
	public static Connection getConnection() throws SQLException, IOException
	   {
	      Properties props = new Properties();
	      FileInputStream in = new FileInputStream("db.properties");
	      props.load(in);
	      in.close();

	      String drivers = props.getProperty("driver");
	      if (drivers != null) System.setProperty("driver", drivers);
	      String url = props.getProperty("url");
	      String username = props.getProperty("username");
	      String password = props.getProperty("password");

	      return DriverManager.getConnection(url, username, password);
	   }
}