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BAEL-6100-Add-example-code-for-integer-array-to-strings-using-streams… (#13375)

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* BAEL-6100-Add-example-code-for-integer-array-to-strings-using-streams-tutorial

* BAEL-6100 remove wrongly added README update

* BAEL-6100 Add interger array to single string example

* BAEL-6100 Correct typo in test class name
This commit is contained in:
sam-gardner 2023-02-18 04:23:54 +00:00 committed by GitHub
parent 4acdb03e61
commit 92864107b9
2 changed files with 95 additions and 0 deletions
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43
core-java-modules/core-java-streams-4/src/main/java/com/baeldung/streams/intarraytostrings/ArrayConversionUtils.java Normal file
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package com.baeldung.streams.intarraytostrings;
import java.util.Arrays;
import java.util.stream.Collectors;
import java.util.stream.IntStream;
import java.util.stream.Stream;
public class ArrayConversionUtils {
public static void createStreamExample() {
int[] intArray = { 1, 2, 3, 4, 5 };
IntStream intStream = Arrays.stream(intArray);
Integer[] integerArray = { 1, 2, 3, 4, 5 };
Stream<Integer> integerStream = Arrays.stream(integerArray);
}
public static String[] convertToStringArray(Integer[] input) {
return Arrays.stream(input)
.map(Object::toString)
.toArray(String[]::new);
}
public static String[] convertToStringArray(int[] input) {
return Arrays.stream(input)
.mapToObj(Integer::toString)
.toArray(String[]::new);
}
public static String[] convertToStringArrayWithBoxing(int[] input) {
return Arrays.stream(input)
.boxed()
.map(Object::toString)
.toArray(String[]::new);
}
public static String convertToString(int[] input){
return Arrays.stream(input)
.mapToObj(Integer::toString)
.collect(Collectors.joining(", "));
}
}

52
core-java-modules/core-java-streams-4/src/test/java/com/baeldung/streams/intarraytostrings/IntArrayToStringUnitTest.java Normal file
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package com.baeldung.streams.intarraytostrings;
import static com.baeldung.streams.intarraytostrings.ArrayConversionUtils.convertToString;
import static com.baeldung.streams.intarraytostrings.ArrayConversionUtils.convertToStringArray;
import static com.baeldung.streams.intarraytostrings.ArrayConversionUtils.convertToStringArrayWithBoxing;
import org.junit.Assert;
import org.junit.Test;
public class IntArrayToStringUnitTest {
@Test
public void whenConvertingIntegers_thenHandleStreamOfIntegers() {
Integer[] integerNumbers = { 1, 2, 3, 4, 5 };
String[] expectedOutput = { "1", "2", "3", "4", "5" };
String[] strings = convertToStringArray(integerNumbers);
Assert.assertArrayEquals(expectedOutput, strings);
}
@Test
public void whenConvertingInts_thenHandleIntStream() {
int[] intNumbers = { 1, 2, 3, 4, 5 };
String[] expectedOutput = { "1", "2", "3", "4", "5" };
String[] strings = convertToStringArray(intNumbers);
Assert.assertArrayEquals(expectedOutput, strings);
}
@Test
public void givenAnIntArray_whenBoxingToInteger_thenHandleStreamOfIntegers() {
int[] intNumbers = { 1, 2, 3, 4, 5 };
String[] expectedOutput = { "1", "2", "3", "4", "5" };
String[] strings = convertToStringArrayWithBoxing(intNumbers);
Assert.assertArrayEquals(expectedOutput, strings);
}
@Test
public void givenAnIntArray_whenUsingCollectorsJoining_thenReturnCommaSeparatedString(){
int[] intNumbers = { 1, 2, 3, 4, 5 };
String expectedOutput = "1, 2, 3, 4, 5";
String string = convertToString(intNumbers);
Assert.assertEquals(expectedOutput, string);
}
}