把数据+类型写入字节数组里这个程序总错，求大神指出错的地方，或者给出正确的代码，感激不尽

Question

package 处理流;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;

public class Demo02 {
public static void main(String[] args) throws IOException{
read(write());
}
//把数据+类型写到字节数组里
public static byte[] write()throws IOException
{
byte[] b2=null;
ByteArrayOutputStream dos=new ByteArrayOutputStream();
DataOutputStream out=new DataOutputStream(
new BufferedOutputStream(dos));
double point=3.14159;
int num=2628;
String str="我是汪洋";
String str02="刘林是我同学";
out.writeDouble(point);
out.writeInt(num);
out.writeUTF(str);
out.writeUTF(str02);
dos.flush();
b2=dos.toByteArray();

    return b2;
}
//从字节数组中获得数据+类型
public static void read(byte[] b2)throws IOException
{
    DataInputStream into=new DataInputStream(
            new BufferedInputStream(
                    new ByteArrayInputStream(b2)));
    System.out.println("point="+into.readDouble());
    System.out.println("num="+into.readInt());
    System.out.println("str="+into.readUTF());
    System.out.println("str02="+into.readUTF());
}

}

Answer 1

out.writeUTF(str02);
out.flush();//加上这句，把流输出到dos
dos.flush();