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Java 8 - find element in List
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In this article, we would like to show you how to find an element in List in Java 8.
In this approach we're gonna:
- invoke
stream()on the list, - call
collect()method withCollector.toList()that collects all Stream elements into a List instance.
In this example, we use Java 8 Stream API to find the first occurrence of User named Tom in the List.
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import java.io.IOException;2
import java.util.ArrayList;3
import java.util.Arrays;4
import java.util.List;5
import java.util.stream.Collectors;6
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public class Example {8
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public static void main(String[] args) throws IOException {10
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// Create list of users --------------------12
List<User> users = new ArrayList<>(Arrays.asList(13
new User("Tom", 20),14
new User("Kate", 21),15
new User("Ann", 22)16
));17
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// find an element in List --------------------19
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List<User> foundUsers = users.stream()21
.filter(user -> "Tom".equals(user.getName()))22
.collect(Collectors.toList());23
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System.out.println(foundUsers);25
}26
}Output:
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User{ name='Tom', age=20 }Note:
We create new list -
foundUsersto collect the result in case there are many users namedTom.
Note:
In the section below you can find the implementation of the User class
User.java:
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public class User {2
private final String name;3
private final int age;4
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public User(String name, int age) {6
this.name = name;7
this.age = age;8
}9
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public String getName() {11
return name;12
}13
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public String toString() {16
return "User{ " +17
"name='" + name + '\'' +18
", age=" + age +19
" }";20
}21
}