java 字节流读取图片，字符流读取，二进制读取

二进制文件读取图片，其实就是用字节流读取图片。其实就是用Java中提供的对字节流操作的类去操控图片文件

 

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();
}
}