数据流DataInputStream和内存流ByteArrayInputStream

public static void main(String[] args) throws IOException
{
writeData();
readData();
}
public static void readData()throws IOException
{
DataInputStream dis =new DataInputStream(new FileInputStream("data.txt"));

System.out.println(dis.readDouble());
System.out.println(dis.readBoolean());
System.out.println(dis.readChar());
dis.close();
}

public static void writeData()throws IOException
{
DataOutputStream dos = new DataOutputStream(new FileOutputStream("data.txt"));

dos.writeDouble(66.78);
dos.writeBoolean(false);
dos.writeChar('k');

dos.close();
}

public static void main(String[] args) throws IOException
{
//内存流：
//ByteArrayInputStream:从内存中读，
//ByteArrayInputStream(byte[] buf)//从字节数组中读

//ByteArrayOutputStream:向内存中写
//内部有一个字节数组，数据被写到该数组中

byte[] arr = "hello,大家好!".getBytes();
ByteArrayInputStream bis = new ByteArrayInputStream(arr);

ByteArrayOutputStream bos = new ByteArrayOutputStream();

byte[] a = new byte[1024];
int len = 0;
while((len = bis.read(a))!=-1)
{
bos.write(a,0,len);
}
//得到ByteArrayOutputStream对象内部数组中的数据
//将对象内部数组中的数据写入data
byte[] data = bos.toByteArray();
System.out.println(new String(data));

}