java 如何在java中将两个对象列表合并为一个
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How to join two list of objects into one in java
提问by user359187
Hi i have two ArrayList of objects and i need to merge it as a single list. Here is my requirement
嗨，我有两个 ArrayList 对象，我需要将它合并为一个列表。这是我的要求
My firstList
我的第一个列表
ListA
列表A
{StaffFirstName=f2, resourceId=2, totalcost=18055.0, totalPercentageInvolvment=550, ResourceCost=2300, staffRole=tl}
and listB
和列表B
{sixthmonth=60, fourthmonth=40, firstmonth=10, fifthmonth=50, secondmonth=20, `thirdmonth=30}`
and i need the result to be
我需要结果是
Result
结果
{StaffFirstName=f2, resourceId=2, totalcost=18055.0, totalPercentageInvolvment=550, ResourceCost=2300, staffRole=tl, sixthmonth=60, fourthmonth=40, firstmonth=10, fifthmonth=50, secondmonth=20, thirdmonth=30}
EDIT!
编辑！
Actually my Both list are arrayList so my listA will be
实际上我的两个列表都是 arrayList 所以我的 listA 将是
{StaffFirstName=f2, resourceId=2, totalcost=18055.0, totalPercentageInvolvment=550, ResourceCost=2300, staffRole=tl}
{StaffFirstName=demo35, resourceId=3, totalcost=19625.0, totalPercentageInvolvment=785, ResourceCost=2500, staffRole=sweeper}
and list B will be
和列表 B 将是
{sixthmonth=100, fourthmonth=30, firstmonth=40, fifthmonth=25, secondmonth=100, thirdmonth=90}
{sixthmonth=100, fourthmonth=30, firstmonth=40, fifthmonth=25, secondmonth=100, thirdmonth=90}
and the result should be
结果应该是
{StaffFirstName=f2, resourceId=2, totalcost=18055.0, totalPercentageInvolvment=550, ResourceCost=2300, staffRole=tl, sixthmonth=60, fourthmonth=40, firstmonth=10, fifthmonth=50, secondmonth=20, thirdmonth=30}
{StaffFirstName=demo35, resourceId=3, totalcost=19625.0, totalPercentageInvolvment=785, ResourceCost=2500, staffRole=sweeper, sixthmonth=100, fourthmonth=30, firstmonth=40, fifthmonth=25, secondmonth=100, thirdmonth=90}
That means each row of my tow list must be append my row wise. If i use addAllfunction the two list just append like this
这意味着我的拖车列表的每一行都必须明智地附加我的行。如果我使用addAll函数，两个列表就这样附加
{StaffFirstName=f2, resourceId=2, totalcost=18055.0, totalPercentageInvolvment=550, ResourceCost=2300, staffRole=tl}
{StaffFirstName=demo35, resourceId=3, totalcost=19625.0, totalPercentageInvolvment=785, ResourceCost=2500, staffRole=sweeper}
{sixthmonth=60, fourthmonth=40, firstmonth=10, fifthmonth=50, secondmonth=20, thirdmonth=30}
{sixthmonth=100, fourthmonth=30, firstmonth=40, fifthmonth=25, secondmonth=100, thirdmonth=90}. But i need to append the two list row wise. Is it possible?
回答by Andy Thomas
Given:
鉴于：
List<MyClass> listA, listB;
Try this:
试试这个：
List<MyClass> union = new ArrayList<MyClass>();
union.addAll( listA );
union.addAll( listB );
回答by pcalcao
I'm not quite sure that what you have is an ArrayList(from the output), but even so, if it's a class that implements the Collectioninterface, you can use the addAllmethod, independent of the exact class (as long as the objects are of the same type).
我不太确定你所拥有的是一个ArrayList（来自输出），但即便如此，如果它是一个实现Collection接口的类，你可以使用该addAll方法，独立于确切的类（只要对象是同类型）。
http://docs.oracle.com/javase/6/docs/api/java/util/Collections.html#addAll(java.util.Collection, T...)
http://docs.oracle.com/javase/6/docs/api/java/util/Collections.html#addAll(java.util.Collection, T...)
回答by ametren
If these are ArrayList<> objects containing the same type, you can use this:
如果这些是包含相同类型的 ArrayList<> 对象，则可以使用：
list1.addAll(list2);
and it should work fine for what you want.
它应该可以很好地满足您的需求。
回答by NIlesh Sharma
Type is the type of array....
类型是数组的类型....
Type[] concat(Type[] listA, Type[] listB)
{
Type[] list= new Type[listA.length+listB.length];
System.arraycopy(listA, 0, list, 0, listA.length);
System.arraycopy(listB, 0, list, listA.length, listB.length);
return list;
}
