How to Sort a List Based on the Order of Another List in Java?

Sorting Lists Based on a Given Order

In Java, it is possible to sort one list based on the order of another list. This can be useful in various scenarios, such as maintaining the order of items when retrieving them from a database or reordering a list of elements based on user preferences.

To accomplish this, we can leverage Java's Collections.sort() method, which takes a Comparator as an argument. A Comparator defines the ordering rules for the elements in the list.

Java 8 Solution

In Java 8, we can use Comparator.comparing() to sort the list based on the indexOf() method of the ordered list. The following code snippet demonstrates this approach:

<code class="java">Collections.sort(listToSort, Comparator.comparing(item -> listWithOrder.indexOf(item)));</code>

Optimized Java 8 Solution

For improved performance, we can use Comparator.comparingInt() instead, as seen in the following code:

<code class="java">listToSort.sort(Comparator.comparingInt(listWithOrder::indexOf));</code>

By sorting one list based on the order of another, we can ensure that the elements in the sorted list maintain the same relative order as the elements in the ordered list. This is a powerful technique that can be used for a variety of applications in Java programming.

The above is the detailed content of How to Sort a List Based on the Order of Another List in Java?. For more information, please follow other related articles on the PHP Chinese website!