现在需要clone的对象是HashMap needCloneMap，要将其clone为cloneMap.

操作如下：

ByteArrayOutputStream out = new ByteArrayOutputStream();
ObjectOutputStream objectout = new ObjectOutputStream(out);
objectout.writeObject(needCloneMap);

ByteArrayInputStream in = new ByteArrayInputStream(out.toByteArray());
ObjectInputStream objectin = new ObjectInputStream(in);
HashMap cloneMap = (HashMap) objectin.readObject();

克隆完毕。

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