//数据流传输

import java.io.*;

public class Index{

    public static void main(String[] args) throws Exception{

        //把这段当公式用就可以了

        //不用记忆

        ByteArrayOutputStream zjszl = new ByteArrayOutputStream();

        DataOutputStream sjl = new DataOutputStream(zjszl);

        long aa = 123456789;

        sjl.writeLong(aa);

        byte[] zjsz = zjszl.toByteArray();

        ByteArrayInputStream srl = new ByteArrayInputStream(zjsz);

        DataInputStream sjsr = new DataInputStream(srl);

        long ss;

        ss = sjsr.readLong();

        System.out.println("ss="+ss);

    }

}