How to convert a Java array into a List: simple method analysis, specific code examples are required
In Java programming, arrays and Lists are common data structures. Sometimes, we need to convert an array into a List to facilitate various operations and processing. This article will introduce several simple methods to help you convert Java arrays into Lists, and provide specific code examples.
Method 1: Use the asList() method of the Arrays class
The Arrays class is a tool class provided by Java. There is a very convenient method asList() that can convert an array into a List. . The following is a specific code example:
import java.util.Arrays; import java.util.List; public class ArrayToListExample { public static void main(String[] args) { String[] array = {"apple", "banana", "orange"}; List<String> list = Arrays.asList(array); System.out.println(list); } }
In the above code, we first create an array array of String type, containing three elements. Then, convert the array into a List through the Arrays.asList() method, and assign the result to the list variable. Finally, use the System.out.println() method to print the output list to view the converted results.
Method 2: Use the addAll() method of the Collections class
The Collections class is another tool class provided by Java. It has an addAll() method that can add all elements of an array. into an existing List. The following is a specific code example:
import java.util.ArrayList; import java.util.Collections; import java.util.List; public class ArrayToListExample { public static void main(String[] args) { String[] array = {"apple", "banana", "orange"}; List<String> list = new ArrayList<>(); Collections.addAll(list, array); System.out.println(list); } }
In the above code, we first create an array array of String type, containing three elements. Then, first create an empty ArrayList and assign it to the list variable. Next, use the Collections.addAll() method to add all elements of the array to the list. Finally, use the System.out.println() method to print the output list to view the converted results.
Method 3: Use Stream API
Java 8 introduced the Stream API, which provides a more concise and smooth way to process collection data. Through the Stream API, we can easily convert arrays into Lists. The following is a specific code example:
import java.util.Arrays; import java.util.List; import java.util.stream.Collectors; public class ArrayToListExample { public static void main(String[] args) { String[] array = {"apple", "banana", "orange"}; List<String> list = Arrays.stream(array).collect(Collectors.toList()); System.out.println(list); } }
In the above code, we first create an array array of String type, containing three elements. Then, use the Arrays.stream() method to convert the array into a stream. Then, use the collect() method of the stream, combined with the Collectors.toList() method, to collect the elements in the stream into a List. Finally, use the System.out.println() method to print the output list to view the converted results.
Summary:
Through the introduction of this article, we have learned three simple methods to convert Java arrays into Lists. First, you can use the asList() method of the Arrays class to directly convert the array into a List. Secondly, you can use the addAll() method of the Collections class to add all elements of the array to an existing List. Finally, you can use the Stream API to convert the array into a stream through the Arrays.stream() method, and collect the elements in the stream into a List using the collect() method and Collectors.toList() method. Choosing the appropriate method according to the actual situation can make conversion between arrays and Lists more convenient.
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