java 字节流读取图片，字符流读取，二进制读取

原文地址：http://blog.csdn.net/jianhua0902/article/details/8518530

import java.io.*;
import javax.swing.*;
public class Start
{
	public static void main(String args[]) throws Exception{

		//源文件，必须存在，路径可选
		File sf = new File("H:/javapro/files/source.jpg");	

		//目的文件，因为要向其中写入，指定文件可以不存在，由程序生成
		File df = new File("H:/javapro/files/dest.jpg");
		new ReadWriteGra(sf,df);
		new UseGra(df);
	}
}

class ReadWriteGra 
{
	FileInputStream in = null;
	FileOutputStream out = null;
	public ReadWriteGra(File sourceFile,File destFile) throws Exception{
		byte[] buf = new byte[1024];
		int len = 0;
		in = new FileInputStream(sourceFile);
		out = new FileOutputStream(destFile,true);
		while( (len = in.read(buf)) != -1 ){
			out.write(buf,0,len);
		}
		out.close();
	}
}
class UseGra extends JFrame
{
	public UseGra(File picFile) throws Exception{

		this.setVisible(true);
		this.setResizable(false);
		this.setLayout(null);
		this.setBounds(600, 200, 400, 370);
		this.setDefaultCloseOperation(DISPOSE_ON_CLOSE);
		JPanel p1 = (JPanel)this.getContentPane();
		p1.setOpaque(false);
		p1.setLayout(null);
		InputStream is = new FileInputStream(picFile);
		ByteArrayOutputStream baos = new ByteArrayOutputStream();
		int b = 0;
		while((b = is.read())!=-1){
			baos.write(b);
		}
		ImageIcon image = new ImageIcon(baos.toByteArray());
		JLabel background = new JLabel(image);
		this.getLayeredPane().add(background, new Integer(Integer.MIN_VALUE));
		background.setBounds(0, 0, image.getIconWidth(), image.getIconHeight());
		JButton bt = new JButton("Test_Button");
		p1.add(bt);
		bt.setBounds(10,10,150,25);
		validate();
	}
}