如何在 java 中将两个对象列表合并为一个

Question

嗨，我有两个对象ArrayList，我需要将其合并为一个列表。这是我的要求

My firstList

列表A

{StaffFirstName=f2, resourceId=2, totalcost=18055.0, totalPercentageInvolvment=550, ResourceCost=2300, staffRole=tl}

和列表B

{sixthmonth=60, fourthmonth=40, firstmonth=10, fifthmonth=50, secondmonth=20, `thirdmonth=30}`

我需要的结果是

后果

{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}

编辑！

实际上我的两个列表都是数组列表，所以我的列表也是

{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}

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}

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}

这意味着我的tow列表中的每一行都必须追加到我的行中。如果我使用< code>addAll函数，这两个列表就像这样追加

{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?

Answer 1

如果这些是数组列表

list1.addAll(list2);

它应该适用于您想要的。

Answer 2

我不太确定你有一个＜code＞ArrayList＜/code＞（来自输出），但即使如此，如果它是一个实现＜code＞Collection＜/code’接口的类，你可以使用＜code＞addAll＜/code〕方法，而不依赖于确切的类（只要对象是同一类型的）。

http://docs.oracle.com/javase/6/docs/api/java/util/Collections.html#addAll（java.util.收藏，T…）

Answer 3

鉴于:

   List<MyClass> listA, listB;

试试这个：

   List<MyClass> union = new ArrayList<MyClass>();
   union.addAll( listA );
   union.addAll( listB );

编辑（Java 8或更高版本）

在Java 8或更高版本中，可以使用流在单个表达式中连接列表。

List<MyClass> union = Stream.concat( listA.stream(), listB.stream())
            .collect( Collectors.toList());