DataIO & ByteArrayIo

import java.io.*;

public class TestFileInputStream {

    public static void main(String[] args) {
        ByteArrayOutputStream baos = 
                new ByteArrayOutputStream();
        DataOutputStream dos = 
                new DataOutputStream(baos);
        try {
            dos.writeDouble(Math.random());
            dos.writeBoolean(true);
            ByteArrayInputStream bais = 
                    new ByteArrayInputStream(baos.toByteArray());
            System.out.println(bais.available());//bais中有多少字节
            DataInputStream dis = 
                    new DataInputStream(bais);
            System.out.println(dis.readDouble());//先写的先读
            System.out.println(dis.readBoolean());
            dos.close();
            dis.close();
        }catch(IOException e) {
            e.printStackTrace();
        }
    }
}