<div id="readability-page-1" class="page"><div><div><a rel="noopener" href="/@sindepal?source=post_page-----187656327376--------------------------------"><img alt="신상훈" src="https://miro.medium.com/fit/c/56/56/0*IyUJXQViJJEmVWaW.jpg" width="28" height="28"></a></div>Java Basic<pre>public class StreamTest {public static void main(String[] args) { //jdk 1.9 이상 일경우 List.of 사용 //List&lt;Integer&gt; numbers = List.of(1,2,3,4,5,6,7); List&lt;Integer&gt; numbers = Arrays.asList(1,2,3,4,5,6,7); beforPrintAllNumbersInList(numbers); beforPrintEvenNumbersInListStructured(numbers); }private static void beforPrintAllNumbersInList(List&lt;Integer&gt; numbers ) { for(int number: numbers ) { System.out.println(number); } } private static void beforPrintEvenNumbersInListStructured(List&lt;Integer&gt; numbers ) { for(int number: numbers ) { if(number % 2 == 0) { System.out.println(number); } } }}</pre><h2 id="301a">Java Stream</h2><pre> import java.util.Arrays; import java.util.List;public class StreamTest {public static void main(String[] args) { //jdk 1.9 이상 일경우 List.of 사용 //List&lt;Integer&gt; numbers = List.of(1,2,3,4,5,6,7); List&lt;Integer&gt; numbers = Arrays.asList(1,2,3,4,5,6,7); afterPrintAllNumbersInList(numbers); System.out.println(“======”); afterPrintEvenAllNumbersInListFunctional(numbers); System.out.println(“======String======”); List&lt;String&gt; str = Arrays.asList(“shin”,”sanghoon”,”sindepal”,”Shinyul”,”wow”); afterPrintStringLength(str); }private static void print(int number) { System.out.println(number); }private static boolean isEven(int number) { return number%2 == 0; }private static void afterPrintAllNumbersInList(List&lt;Integer&gt; numbers) { // ::(콜론) 참조 구문 numbers.stream().forEach(StreamTest::print); numbers.stream().forEach(System.out::println); }private static void afterPrintEvenAllNumbersInListFunctional(List&lt;Integer&gt; numbers) { // ::(콜론) 참조 구문 numbers.stream() .filter(StreamTest::isEven) .forEach(StreamTest::print); numbers.stream() .filter( number -&gt; number%2 == 0 ) .forEach(StreamTest::print); } private static void afterPrintCubesOfNumbersInListFunctional(List&lt;Integer&gt; numbers) { numbers.stream() .filter( number -&gt; number%2 == 0 ) .map(number -&gt; number * number ) .forEach(StreamTest::print); } private static void afterPrintStringLength(List&lt;String&gt; str) { str.stream() .map(text -&gt; text + “::” + text.length()) .forEach(System.out::println); }}</pre></div></div>

Stories by 신상훈 on Medium

Java Basic
public class StreamTest {
public static void main(String[] args) {
 //jdk 1.9 이상 일경우 List.of 사용
 //List<Integer> numbers = List.of(1,2,3,4,5,6,7);
 List<Integer> numbers = Arrays.asList(1,2,3,4,5,6,7);
 beforPrintAllNumbersInList(numbers);
 beforPrintEvenNumbersInListStructured(numbers);
 }
private static void beforPrintAllNumbersInList(List<Integer> numbers ) {
 for(int number: numbers ) {
 System.out.println(number);
 }
 }
 private static void beforPrintEvenNumbersInListStructured(List<Integer> numbers ) {
 for(int number: numbers ) {
 if(number % 2 == 0) {
 System.out.println(number);
 }
 }
 }
}
Java Stream
import java.util.Arrays;
import java.util.List;
public class StreamTest {public static void main(String[] args) {
 //jdk 1.9 이상 일경우 List.of 사용
 //List<Integer> numbers = List.of(1,2,3,4,5,6,7);
 List<Integer> numbers = Arrays.asList(1,2,3,4,5,6,7);
 afterPrintAllNumbersInList(numbers);
 System.out.println(“======”);
 afterPrintEvenAllNumbersInListFunctional(numbers);
 
 System.out.println(“======String======”);
 List<String> str = Arrays.asList(“shin”,”sanghoon”,”sindepal”,”Shinyul”,”wow”);
 afterPrintStringLength(str);
 }
private static void print(int number) {
 System.out.println(number);
 }
private static boolean isEven(int number) {
 return number%2 == 0;
 }
private static void afterPrintAllNumbersInList(List<Integer> numbers) {
 // ::(콜론) 참조 구문
 numbers.stream().forEach(StreamTest::print);
 numbers.stream().forEach(System.out::println);
 }
private static void afterPrintEvenAllNumbersInListFunctional(List<Integer> numbers) {
 // ::(콜론) 참조 구문
 numbers.stream()
 .filter(StreamTest::isEven)
 .forEach(StreamTest::print);
 numbers.stream()
 .filter( number -> number%2 == 0 )
 .forEach(StreamTest::print);
 }
 private static void afterPrintCubesOfNumbersInListFunctional(List<Integer> numbers) {
 numbers.stream()
 .filter( number -> number%2 == 0 )
 .map(number -> number * number )
 .forEach(StreamTest::print);
 }
 private static void afterPrintStringLength(List<String> str) {
 str.stream()
 .map(text -> text + “::” + text.length())
 .forEach(System.out::println);
 
 }
}

Java Stream - Step 01

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