将以下代码重新用java写，功能和逻辑不变，语句需要变化public boolean outBook(String bookId , int num) { Book b = getById(bookId); if(b == null ) return false; if(b.getIsbn().equals(bookId)) { b.setStore(b.getStore()-num); return true; } return false; } /* * printf("%5d",a) */ public int buyBook(String bookId,int num) { Book b = getById(bookId); if(b == null) return -1; if(b.getStore() >= num) return 1; return 0; } public List<String> getEXNames(int option){ return ExFactory.getAllEX(); } public EX buyEx(int exCode) { return ExFactory.create(exCode); }

public boolean outBook(String bookId, int num) {
Book b = getById(bookId);
if (b == null) {
return false;
}
if (b.getIsbn().equals(bookId)) {
b.setStore(b.getStore() - num);
return true;
}
return false;
}

public int buyBook(String bookId, int num) {
Book b = getById(bookId);
if (b == null) {
return -1;
}
if (b.getStore() >= num) {
return 1;
}
return 0;
}

public List<String> getEXNames(int option) {
return ExFactory.getAllEX();
}

public EX buyEx(int exCode) {
return ExFactory.create(exCode);
}