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Java'da Dizilere nasıl katılınır? 3 yol: Apache Commons ArrayUtils, Java 8 Akışları ve Basit API'ler

Yayınlanan: 2022-01-20
Java'da Dizilere nasıl katılınır? 3 yol - Apache Commons ArrayUtils, Java 8 Akışları ve Basit API'ler

Bu eğitimde Java Dizilerine katılabileceğimiz farklı yolları inceleyeceğiz.

Aşağıdaki sorulardan herhangi birine sahipseniz doğru yerdesiniz:

  • Java'da iki diziyi nasıl birleştirebilirim?
  • Java'da İki Dizi Nasıl Birleştirilir?
  • Java'da Dizileri Birleştirmenin 3 Yolu
  • Java'da Ayırıcı ile İlkel Dizisine Katılın

Java'da dizilere katılmanın üç yolu vardır.

  1. Apache Common yardımcı programını kullanarak Diziye Katılın
  2. Java8 Akış işlemini kullanarak Diziye Katılın
  3. Standart Java API'lerini kullanarak Diziye Katılın

Başlayalım:

Java sınıfı CrunchifyJoinArrays3Ways.java oluşturun.

Java kodunun altına dosyaya koyun.

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package crunchify . com . tutorial ;
 
import org . apache . commons . lang3 . ArrayUtils ;
 
import java . lang . reflect . Array ;
import java . util . Arrays ;
import java . util . stream . IntStream ;
import java . util . stream . Stream ;
 
/**
* @author Crunchify.com
* <p>
* In Java how to join Arrays? 3 ways: Apache Commons ArrayUtils, Java 8 Streams and Simple APIs.
* Version: 1.0.3
*/
public class CrunchifyJoinArrays3Ways {
     public static void main ( String [ ] args ) {
 
         crunchifyPrint ( "Original String Array1: [google, twitter]" ) ;
         crunchifyPrint ( "Original String Array2: [apple, microsoft]" ) ;
         crunchifyPrint ( "Original Integer Array1: [111, 444]" ) ;
         crunchifyPrint ( "Original Integer Array2: [222, 555]\n" ) ;
         // Join Array using Apache Common utility
         joinArrayUsingApacheCommon ( ) ;
 
         // Join Array using Java8 Stream operation
         joinArrayUsingJava8Stream ( ) ;
 
         // Join Array using Standard Java APIs
         joinArrayUsingJavaAPI ( ) ;
     }
 
     // Method-1: Join Array using Apache Common utility
     private static void joinArrayUsingApacheCommon ( ) {
 
         String [ ] company1 = new String [ ] { "google" , "twitter" } ;
         String [ ] company2 = new String [ ] { "apple" , "microsoft" } ;
 
         // from org.apache.commons.lang3 maven dependency
         String [ ] crunchifyResult = ArrayUtils . addAll ( company1 , company2 ) ;
 
         crunchifyPrint ( "From Method-1: addAll() - String ==> " + Arrays . toString ( crunchifyResult ) ) ;
 
         int [ ] crunchifyArray1 = new int [ ] { 111 , 444 } ;
         int [ ] crunchifyArray2 = new int [ ] { 222 , 555 } ;
 
         int [ ] crunchifyResult2 = ArrayUtils . addAll ( crunchifyArray1 , crunchifyArray2 ) ;
 
         crunchifyPrint ( "From Method-1: addAll() - Integer ==> " + Arrays . toString ( crunchifyResult2 ) ) ;
     }
 
     // Simple Java Print Method
     private static void crunchifyPrint ( String result ) {
         System . out . println ( result ) ;
     }
 
     // Method-2: Join Array using Java8 Stream operation
     private static void joinArrayUsingJava8Stream ( ) {
         String [ ] company1 = new String [ ] { "google" , "twitter" } ;
         String [ ] company2 = new String [ ] { "apple" , "microsoft" } ;
 
         // Stream.of() - returns a sequential ordered stream whose elements are the specified values.
         // A sequence of elements supporting sequential and parallel aggregate operations. The following example illustrates an aggregate operation using Stream and IntStream:
         //
         //     int sum = widgets.stream()
         //                      .filter(w -> w.getColor() == RED)
         //                      .mapToInt(w -> w.getWeight())
         //                      .sum();
         String [ ] result = Stream . of ( company1 , company2 ) . flatMap ( Stream : : of ) . toArray ( String [ ] : : new ) ;
         crunchifyPrint ( "\nFrom Method-2: Stream.of() ==> " + Arrays . toString ( result ) ) ;
 
         int [ ] crunchifyArray1 = new int [ ] { 111 , 444 } ;
         int [ ] crunchifyArray2 = new int [ ] { 222 , 555 } ;
 
         // Arrays.stream() - returns a sequential IntStream with the specified array as its source.
         int [ ] crunchifyResult2 = IntStream . concat ( Arrays . stream ( crunchifyArray1 ) , Arrays . stream ( crunchifyArray2 ) ) . toArray ( ) ;
 
         crunchifyPrint ( "From Method-2: IntStream.concat() ==> " + Arrays . toString ( crunchifyResult2 ) ) ;
     }
 
     // Method-3: Join Array using Standard Java APIs
     private static void joinArrayUsingJavaAPI ( ) {
         String [ ] company1 = new String [ ] { "google" , "twitter" } ;
         String [ ] company2 = new String [ ] { "apple" , "microsoft" } ;
 
         String [ ] crunchifyResult = crunchifyJoinGenericArray ( company1 , company2 ) ;
 
         crunchifyPrint ( "\nFrom Method-3: crunchifyJoinArrayusingGeneric() ==> " + Arrays . toString ( crunchifyResult ) ) ;
 
         int [ ] crunchifyArray1 = new int [ ] { 111 , 444 } ;
         int [ ] crunchifyArray2 = new int [ ] { 222 , 555 } ;
 
         int [ ] crunchifyResult2 = crunchifyJoinIntegerArray ( crunchifyArray1 , crunchifyArray2 ) ;
 
         // Arrays.toString() Returns a string representation of the contents of the specified array.
         // The string representation consists of a list of the array's elements, enclosed in square brackets ("[]").
         // Adjacent elements are separated by the characters ", " (a comma followed by a space).
         // Elements are converted to strings as by String.valueOf(int). Returns "null" if a is null.
         crunchifyPrint ( "From Method-3: joinArray() ==> " + Arrays . toString ( crunchifyResult2 ) ) ;
     }
 
     @ SafeVarargs
     private static < T > T [ ] crunchifyJoinGenericArray ( T [ ] . . . crunchifyArrays ) {
         int crunchify = 0 ;
         for ( T [ ] crunchifyArray : crunchifyArrays ) {
             crunchify += crunchifyArray . length ;
         }
 
         //T[] result = new T[crunchify];
         final T [ ] crunchifyResult = ( T [ ] ) Array . newInstance ( crunchifyArrays [ 0 ] . getClass ( ) . getComponentType ( ) ,
                 crunchify ) ;
 
         int crunchifyOffset = 0 ;
         for ( T [ ] crunchifyArray : crunchifyArrays ) {
 
             // Copies an array from the specified source array, beginning at the specified position, to the specified position of the destination array.
             // A subsequence of array components are copied from the source array referenced by src to the destination array referenced by dest.
             // The number of components copied is equal to the length argument.
             // The components at positions srcPos through srcPos+length-1 in the source array are copied into positions destPos through destPos+length-1, respectively, of the destination array.
             System . arraycopy ( crunchifyArray , 0 , crunchifyResult , crunchifyOffset , crunchifyArray . length ) ;
             crunchifyOffset += crunchifyArray . length ;
         }
 
         return crunchifyResult ;
     }
 
     private static int [ ] crunchifyJoinIntegerArray ( int [ ] . . . crunchifyArrays ) {
         int crunchify = 0 ;
         for ( int [ ] crunchifyArray : crunchifyArrays ) {
             crunchify += crunchifyArray . length ;
         }
 
         final int [ ] crunchifyResult = new int [ crunchify ] ;
 
         int crunchifyOffset = 0 ;
         for ( int [ ] crunchifyArray : crunchifyArrays ) {
 
             System . arraycopy ( crunchifyArray , 0 , crunchifyResult , crunchifyOffset , crunchifyArray . length ) ;
             crunchifyOffset += crunchifyArray . length ;
         }
 
         return crunchifyResult ;
     }
 
}

Bazı Java API ayrıntılarına bir göz atalım.

java.lang.System.arraycopy():

Java dizisiKopya Örneği

java.util.Arrays.toString():

Java toString Örneği

java.util.stream():

Java Akışı.Örnek
Java Akış Örneği

Programı bir Java Programı olarak çalıştırın ve aşağıdakiyle aynı sonucu görmelisiniz.

IntelliJ IDEA konsol çıktısı:

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/ Library / Java / JavaVirtualMachines / jdk - 15.jdk / Contents / Home / bin / java - javaagent : / Applications / IntelliJ IDEA . app / Contents / lib / idea_rt . jar = 50249 : / Applications / IntelliJ IDEA . app / Contents / bin - Dfile . encoding = UTF - 8 - classpath / Users / app / crunchify / github / CrunchifyTutorials / target / classes : / Users / app / crunchify / github / CrunchifyTutorials / WebContent / WEB - INF / lib / zxing - 2.1.jar / Users / app / . m2 / repository / commons - collections / commons - collections / 3.2.1 / commons - collections - 3.2.1.jar / spring - context - support - 5.1.3.RELEASE.jar crunchify . com . tutorial . CrunchifyJoinArrays3Ways
 
Original String Array1 : [ google , twitter ]
Original String Array2 : [ apple , microsoft ]
Original Integer Array1 : [ 111 , 444 ]
Original Integer Array2 : [ 222 , 555 ]
 
From Method - 1 : addAll ( ) - String == > [ google , twitter , apple , microsoft ]
From Method - 1 : addAll ( ) - Integer == > [ 111 , 444 , 222 , 555 ]
 
From Method - 2 : Stream . of ( ) == > [ google , twitter , apple , microsoft ]
From Method - 2 : IntStream . concat ( ) == > [ 111 , 444 , 222 , 555 ]
 
From Method - 3 : crunchifyJoinArrayusingGeneric ( ) == > [ google , twitter , apple , microsoft ]
From Method - 3 : joinArray ( ) == > [ 111 , 444 , 222 , 555 ]
 
Process finished with exit code 0

Java Dizilerini birleştirmenin başka bir yolu varsa veya herhangi bir istisna alırsanız lütfen bana bildirin.