Streams Filter Example

in this tutorial, we will show you some Java 8 examples to illustrate stream filter (), collect () use, Findany () and OrElse ().
1. Streams filter () and collect ()

Before 1.1 Java 8, the filter List looks like this: Beforejava8.java

package Com.mkyong.java8;
Import java.util.ArrayList;
Import Java.util.Arrays;

Import java.util.List; public class BeforeJava8 {public static void main (string[] args) {list<string> lines = Arrays.aslist
        ("Spring", "Node", "Mkyong");
        list<string> result = Getfilteroutput (lines, "Mkyong");    for (String Temp:result) {System.out.println (temp); output:spring, node}} private static list<string> Getfilteroutput (list<string> lines,
        String Filter {list<string> result = new arraylist<> (); for (String line:lines) {if (!)
            Mkyong ". Equals (line)) {//We dont like mkyong result.add (line);
    } return result; }

}
 

Output

Spring
Node

1.2 In Java 8, an example of a stream equivalent. Filter () Filters the list, and collect () is converted to flow into one list. Nowjava8.java

Package com.mkyong.java8;

Import Java.util.Arrays;
Import java.util.List;
Import java.util.stream.Collectors;

public class NowJava8 {public

    static void Main (string[] args) {

        list<string> lines = arrays.aslist ("Spring "," Node "," Mkyong ");

        list<string> result = Lines.stream ()                //convert list to stream
                . Filter (line->!) Mkyong ". Equals (line))     //We dont like Mkyong
                . Collect (Collectors.tolist ());              Collect the output and convert streams to a List

        Result.foreach (system.out::p rintln);                output:spring, Node

    }

}

Output

Spring
Node

2. Streams filter (), Findany () and OrElse () Person.java

Package com.mkyong.java8;

public class Person {

    private String name;
    private int age;

    Public person (String name, int age) {
        this.name = name;
        This.age = age;
    }

    GETTERSM Setters, ToString
}

2.1 Before Java 8, you get a person object as shown in the following example: Beforejava8.java

Package com.mkyong.java8;

Import Java.util.Arrays;
Import java.util.List;

public class BeforeJava8 {public

    static void Main (string[] args) {

        list<person> persons = Arrays.aslist (
  new person ("Mkyong", "The New Person" ("
                Jack"), the new person (
                "Lawrence")
        ;

        Person result = getstudentbyname (persons, "Jack");
        SYSTEM.OUT.PRINTLN (result);

    }

    private static person Getstudentbyname (list<person> persons, String name) {person result

        = null;
        for [person Temp:persons] {
            if (name.equals (Temp.getname ())) {result
                = temp;
            }
        }
        return result;
    }

Output

person{name