Use Apache Commons Collections
Use Apache Commons Collections
Overview:
Apache Commons Collections is a widely used Java tool library for processing and operation array and collection data structures.It provides us with a series of powerful tool categories and methods, making it more convenient and efficient for processing and operation array and sets.This article will introduce how to use Apache Commons Collections to process and operate array and set data.
Instructions:
1. Import Apache Commons Collections Library:
First, we need to introduce Apache Commons Collections.You can find the latest version of the library on the official website (https://commons.apache.org/proper/commons-Collects/).Download and include it in your Java project.
2. Treatment of array:
Apache Commons Collections library provides a set of practical methods for array.The following are examples of some commonly used methods:
// The array turned to the list
Integer[] arr = {1, 2, 3, 4, 5};
List<Integer> list = Arrays.asList(arr);
// The list is converted to an array
List<Integer> list = new ArrayList<>();
list.add(1);
list.add(2);
list.add(3);
Integer[] arr = list.toArray(new Integer[0]);
3. Treatment collection:
In addition to array, Apache Commons Collections library also provides various tool classes and methods to handle sets.Here are some examples:
// Collection screening
List<Integer> list = new ArrayList<>();
list.add(1);
list.add(2);
list.add(3);
CollectionUtils.filter(list, number -> number % 2 == 0);
// Collection conversion
List<String> strings = new ArrayList<>();
strings.add("Apple");
strings.add("Banana");
List<Integer> lengths = CollectionUtils.collect(strings, String::length);
// collection sorting
List<Integer> list = new ArrayList<>();
list.add(3);
list.add(1);
list.add(2);
Collections.sort(list, Comparator.naturalOrder());
in conclusion:
Using Apache Commons Collections Library, we can handle and operate array and set data structures more conveniently and efficiently.It provides rich tool categories and methods, so that we can easily convert, screen, sort and various operations.By using these convenient functions, we can reduce the workload of writing lengthy code and improve the readability and maintenance of code.
Java code example:
import org.apache.commons.collections4.CollectionUtils;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
public class ApacheCollectionsExample {
public static void main(String[] args) {
// The array turned to the list
Integer[] arr = {1, 2, 3, 4, 5};
List<Integer> list = Arrays.asList(arr);
System.out.println(list);
// The list is converted to an array
List<Integer> list = new ArrayList<>();
list.add(1);
list.add(2);
list.add(3);
Integer[] arr = list.toArray(new Integer[0]);
System.out.println(Arrays.toString(arr));
// Collection screening
List<Integer> list = new ArrayList<>();
list.add(1);
list.add(2);
list.add(3);
CollectionUtils.filter(list, number -> number % 2 == 0);
System.out.println(list);
// Collection conversion
List<String> strings = new ArrayList<>();
strings.add("Apple");
strings.add("Banana");
List<Integer> lengths = CollectionUtils.collect(strings, String::length);
System.out.println(lengths);
// collection sorting
List<Integer> list = new ArrayList<>();
list.add(3);
list.add(1);
list.add(2);
Collections.sort(list, Comparator.naturalOrder());
System.out.println(list);
}
}
The above is a brief introduction and example code using Apache Commons Collections to process array and collection.I hope this article can help you better understand and use this powerful Java tool library.
