Java从数据库中读取图片到Jpanel

Java从数据库中读取图片到Jpanel

import  java.io.InputStream; import java.sql.Connection; import java.sql.DriverManager; import java.sql.Statement; import java.sql.ResultSet; import javax.swing.JFrame; import javax.swing.JPanel; import javax.imageio.ImageIO; import java.awt.Container; import java.awt.Graphics; import java.awt.image.BufferedImage; public class pictest { public pictest(){ JFrame f=new JFrame(); Container p=f.getContentPane(); ppic pic=null; InputStream in=null; try{ int i=3; String url="****************"; Class.forName("com.mysql.jdbc.Driver"); Connection con=DriverManager.getConnection(url,"***","***"); //连接到 数据库 if(!con.isClosed()) System.out.println("数据库连接成功"); String sql="select * from campusimage"; Statement st=con.createStatement(); ResultSet rs=st.executeQuery(sql); for(int j=0;j<i;j++) rs.next(); if(rs.next()) in=rs.getBinaryStream(1); pic=new ppic(in); rs.close(); st.close(); con.close(); }catch(Exception e){e.printStackTrace();} p.setLayout(null); p.add(pic); f.setBounds(500,400,800,900); f.setVisible(true); f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); } class ppic extends JPanel {   BufferedImage bi; ppic(InputStream in){ try{ bi=ImageIO.read(in); setBounds(0,0,700,600); }catch(Exception e){e.printStackTrace();} } public void paint(Graphics g){ g.drawImage(bi,0,0,700,600,null); } } public static void main(String[] args){ new pictest(); } }

　 　ps：网上许多人都是把数据库中的图片实例化到本地，不仅读取速度慢，而且浪费内存，当时如果你的图片非常小就算了。