备忘总结：

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;



public class 读取的方式 {
	public static void main(String[] args) throws IOException {
		method4();
	}

	private static void method4() throws IOException{//直接开辟一个正好的数组，在文件较大的时候，不建议使用
		// TODO Auto-generated method stub
		FileInputStream fi=new FileInputStream("d:\\meimei.jpg");
		
		FileOutputStream fo=new FileOutputStream("d:\\meimei1.jpg");
		
		byte arr[]=new byte[fi.available()];
		
		fi.read(arr);
		
		fo.write(arr);
	
		fi.close();
		fo.close();
	}

	private static void method3() throws IOException{//使用所给的缓冲区
		// TODO Auto-generated method stub
		FileInputStream fi=new FileInputStream("d:\\meimei.jpg");
		BufferedInputStream bi=new BufferedInputStream(fi);
		
		FileOutputStream fo=new FileOutputStream("d:\\meimei1.jpg");
		BufferedOutputStream bf=new BufferedOutputStream(fo);
		
		int len;
		while((len=bi.read())!=-1)
		{
			bf.write(len);
		}
		bi.close();
		bf.close();
	}

	private static void method2() throws IOException{//添加自制的缓冲区
		// TODO Auto-generated method stub
		FileInputStream fi=new FileInputStream("d:\\meimei.jpg");
		
		FileOutputStream fo=new FileOutputStream("d:\\meimei1.jpg");
		
		byte arr[]=new byte[1024];
		int len;
		while((len=fi.read(arr))!=-1)
		{
			fo.write(arr,0,len);
		}
		fi.close();
		fo.close();
	}

	private static void method1() throws IOException {//一个一个读，效率极低
		// TODO Auto-generated method stub
		FileInputStream fi=new FileInputStream("d:\\meimei.jpg");
		
		FileOutputStream fo=new FileOutputStream("d:\\meimei1.jpg");
		
		int dex;
		while((dex=fi.read())!=-1)
		{
			fo.write(dex);
		}
		fi.close();
		fo.close();
	}
}