When to use ofNullable() method of Stream in Java 9?-Java Tutorial-php.cn

When to use ofNullable() method of Stream in Java 9?

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Release： 2023-08-26 13:21:07

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在Java 9中什么时候使用Stream的ofNullable()方法？

ofNullable() method is a static method of the Stream class. If it is not empty, it returns a sequential Stream containing a single element. , otherwise it returns empty. Java 9 This method was introduced to avoid NullPointerExceptions and avoid null checks for streams. The main goal of using the ofNullable() method is to return an null option when the value is null.

Syntax H2>

static  Stream ofNullable(T t)

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Example 1

import java.util.stream.Stream;
public class OfNullableMethodTest1 {
   public static void main(String args[]) {
      System.out.println("TutorialsPoint");
      int count = (int) Stream.ofNullable(5000).count();
      System.out.println(count);
      System.out.println("Tutorix");
      count = (int) Stream.ofNullable(null).count();
      System.out.println(count);
   }
}

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Output

TutorialsPoint
1
Tutorix
0

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Example 2

import java.util.stream.Stream;
public class OfNullableMethodTest2 {
   public static void main(String args[]) {
      String str = null;
      Stream.ofNullable(str).forEach(System.out::println); // prints nothing in the console
      str = "TutorialsPoint";
      Stream.ofNullable(str).forEach(System.out::println); // prints TutorialsPoint
   }
}

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Output

TutorialsPoint

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