如果list中的对像的编号相同就把对像合并，并将数量相加

比眉伴天荒 2022-06-15 03:56 94阅读 0赞

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个人项目中遇到了一个需求：  
1.假设有产品中有很多零配件，很多产品中的零配件有通用件，也就是编号一样的零配件。  
2.如果客户下订单，订单中有很多产品。  
3.然后要根据这些订单中的产品的数量进行采购，如果他们中有通用件的话就需要把相同编号的数量相加，不然就会出问题的，如果一个产品用500个某零配件，另一个产品也用500个零配件。那么这个零配件就采购1000个才可以，但是在数据库中进行查询的话，按某一个产品进行查询的话就会显示只要500个。  
4.所以我们需要进行订单中的产品相同的零配件进行相加，然后形成一个订单采购表。

所以需求实现的思路就出来了：

List<Object> list = new ArrayList<>();
    		Map<String, Object> map = new HashMap<>();
    		for(Object obj : list){
    			if(map.containsKey(obj.getNo)){
    				Object o = map.get("obj");
    				o.setNum(o.getNum + obj.getNum);
    				map.put(obj.getNo, o);
    			}else{
    				map.put(obj.getNo, obj);
    			}
    		}

具体例子：

//已经售出房源
    		List<HouseData> soldHouse = new ArrayList<>();
    		//库存房源
    		List<HouseData> inventoryHouse = new ArrayList<>();
    //查找所有的上架的房源
    		String houseHql = "from House where projectId = '" + project.getProjectId() + "'";
    		
    		List<House> houseList = baseDao.findByHql(houseHql);
    for(House house : houseList){
    			
    				//查找已经签约的认购，签约代表房子已经售出
    				String contractHql = "from ContractRecords where projectId = '" + project.getProjectId() + "'"
    						+ " and recordStatus = 5 and houseNum = " + house.getHouseNum() + "";
    				ContractRecords cr = (ContractRecords) baseDao.loadObject(contractHql);
    				
    				HouseData houseData = new HouseData();
    				houseData.setBuildArea(house.getBuildArea());
    				houseData.setSoldNum(1);
    				if(cr == null){//库存
    					inventoryHouse.add(houseData);
    				}else{//售出
    					soldHouse.add(houseData);
    				}
    		}
    
    //售出房源过滤
    		Map<Object, Object> map2 = new HashMap<>();
    		//库存房源过滤
    		Map<Object, Object> map3 = new HashMap<>();
    //售出房源
    		for(HouseData sh : soldHouse){
    			if(map2.containsKey(sh.getBuildArea())){
    				HouseData hd = new HouseData();
    				hd.setBuildArea(sh.getBuildArea());
    				Integer a = (Integer) map2.get(sh.getBuildArea());
    				hd.setSoldNum(a + 1);
    				map2.remove(sh.getBuildArea());
    				map2.put(hd.getBuildArea(), hd.getSoldNum());
    			}else{
    				map2.put(sh.getBuildArea(), sh.getSoldNum());
    			}
    		}
    		//库存房源
    		for(HouseData ih : inventoryHouse){
    			if(map3.containsKey(ih.getBuildArea())){
    				HouseData hd = new HouseData();
    				hd.setBuildArea(ih.getBuildArea());
    				hd.setSoldNum((Integer)(map3.get(ih.getBuildArea())) + 1);
    				map3.remove(ih.getBuildArea());
    				map3.put(hd.getBuildArea(), hd.getSoldNum());
    			}else{
    				map3.put(ih.getBuildArea(), ih.getSoldNum());
    			}
    		}
    		
    		//清空集合
    		soldHouse.clear();
    		inventoryHouse.clear();
    		
    		Iterator i1 = map2.entrySet().iterator();
    		Iterator i2 = map3.entrySet().iterator();
    		
    		while(i1.hasNext()){
    			HouseData house = new HouseData();
    			Entry entry = (Entry) i1.next();
    			Object o = entry.getKey();
    			String s = o.toString();
    			Double d = Double.valueOf(s);
    			house.setBuildArea(d);
    			house.setSoldNum(Integer.parseInt(map2.get(d).toString()));
    			soldHouse.add(house);
    		}
    		while(i2.hasNext()){
    			HouseData house = new HouseData();
    			Entry entry = (Entry) i2.next();
    			Object o = entry.getKey();
    			String s = o.toString();
    			Double d = Double.valueOf(s);
    			house.setBuildArea(d);
    			house.setSoldNum(Integer.parseInt(map3.get(d).toString()));
    			inventoryHouse.add(house);
    		}
     		
    		map.put("soldHouse", soldHouse);
    		map.put("inventoryHouse", inventoryHouse);
    		
    		return map;

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