java 小记

if(cartridgeStockList.size()>0){
 Map<Integer, Product> stockMap= new HashMap<Integer, Product>();
 for(int i=0;i<cartridgeStockList.size();i++){
 Product cartridgeProduct=cartridgeStockList.get(i);
 if(stockMap.containsKey(cartridgeProduct.getStockId())){
 int oldQty=stockMap.get(cartridgeProduct.getStockId()).getQty();
 stockMap.get(cartridgeProduct.getStockId()).setQty(oldQty+cartridgeProduct.getQty());
 }else{
 Product newProduct =  new Product();
 SysUtils.copyProduct(cartridgeProduct, newProduct);
 stockMap.put(newProduct.getStockId(), newProduct);
 }
 }

 set对象属性的时候需要创建一个同样的新对象，否则会覆盖原来的对象。