Salesforce Map 优化List

//查出当前quote 对应的 业务机会MapList<Opportunity> opportunityList = [SELECT Id, Unit__c FROM Opportunity WHERE Unit__c!=null AND Id in :oppIdSet];Map<Id, Opportunity> opportunityMap = new Map<Id, Opportunity>();for (Opportunity opp : opportunityList) {opportunityMap.put(opp.Id, opp);}//查出quote对应的opp  line  item  listList<OpportunityLineItem> opportunityLineItemList=[SELECT Id,OpportunityId,PricebookEntryId,Product2Id,Quantity,UnitPrice FROM OpportunityLineItem WHERE OpportunityId in :oppIdSet];Map<Id,List<OpportunityLineItem>> OpportunityLineItemMap=new Map<Id,List<OpportunityLineItem>>();for (OpportunityLineItem opportunityLineItem : opportunityLineItemList) {if (OpportunityLineItemMap.containsKey(opportunityLineItem.OpportunityId) &&OpportunityLineItemMap.get(opportunityLineItem.OpportunityId) != null) {List<OpportunityLineItem> OpportunityLineItemMapList = OpportunityLineItemMap.get(opportunityLineItem.OpportunityId);OpportunityLineItemMapList.add(opportunityLineItem);OpportunityLineItemMap.put(opportunityLineItem.OpportunityId, OpportunityLineItemMapList);} else {OpportunityLineItemMap.put(opportunityLineItem.OpportunityId, new List<OpportunityLineItem>{opportunityLineItem});}}