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java - 二元运算符 '&' 在 Java Card 中的工作原理说明

转载 作者:塔克拉玛干 更新时间:2023-11-02 20:06:03 25 4
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我如何以一种他们能完全理解的方式向一类 Java Card 初学者解释这段代码:

private void getBalance(APDU apdu) {
byte[] buffer = apdu.getBuffer();

// inform system that the applet has finished
// processing the command and the system should
// now prepare to construct a response APDU
// which contains data field
short le = apdu.setOutgoing();

if (le < 2) {
ISOException.throwIt((byte) 0x6A86);
}

// informs the CAD the actual number of bytes
// returned
apdu.setOutgoingLength((byte) 2);

// move the balance data into the APDU buffer
// starting at the offset 0
buffer[0] = (byte) (balance >> 8);

buffer[1] = (byte) (balance & 0xFF);//How do i explain what happens here



// send the 2-byte balance at the offset
// 0 in the apdu buffer
apdu.sendBytes((short) 0, (short) 2);
}

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