InputStream inputStream,OutputStream outputStream

package charpter11;

import java.io.*;

public class TestMain {
    public static void main(String[] args) throws IOException {
        String dir="C:\\Users\\asus\\Desktop\\ceshi\\test";
        String a="a.txt";
        String b="b.txt";
        //File不会创建，也不会检查，错了他也不告诉你
        File file=new File(dir,a);
//        FileInputStream不会自动创建对象，但是会检查是否有这个文件
        InputStream inputStream=new FileInputStream(file);
        //FileOutputStream会自动创建，也会检查，恩，很牛逼
        //会自动创建文件，但是不会创建多级目录下的文件
//        OutputStream outputStream =
//                new FileOutputStream(dir+File.separator+target);

        //不覆盖文件，追加数据
        OutputStream outputStream=
                new FileOutputStream(dir+File.separator+b,true);

//        testRead(inputStream);
        testOut(inputStream,outputStream);
    }
    public static void testRead(InputStream inputStream) throws IOException{
        byte[] buf=new byte[inputStream.available()];
        int length;
        while ((length=inputStream.read(buf))!=-1){
            System.out.println(new String(buf,0,length,"UTF-8"));
        }
        inputStream.close();
    }
    public static void testOut(InputStream inputStream,OutputStream outputStream) throws IOException{
        byte[] buf=new byte[inputStream.available()];
        int length;
        while ((length=inputStream.read(buf))!=-1){
            outputStream.write(buf,0,length);
        }
        outputStream.close();
        inputStream.close();
    }
}