[strToStrArray] Convert String to string array in Java (#12899)

* [strToStrArray] Convert String to string array in Java

* [strToStrArray] add one more example

core-java-modules/core-java-string-operations-5/src/test/java/com/baeldung/strtostrarray/StringToStringArrayUnitTest.java

@@ -0,0 +1,49 @@
+package com.baeldung.strtostrarray;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+
+public class StringToStringArrayUnitTest {
+    private static final String INPUT = "Hi there, nice to meet you!";
+    private static final String FLIGHT_INPUT = "20221018LH720FRAPEK";
+
+    @Test
+    void givenAString_whenConvertToSingletonArray_shouldGetExpectedResult() {
+        String[] myArray = new String[] { INPUT };
+        assertArrayEquals(new String[] { "Hi there, nice to meet you!" }, myArray);
+    }
+
+    @Test
+    void givenAString_whenSplitToWordArray_shouldGetExpectedResult() {
+        String[] myArray = INPUT.split("\\W+");
+        assertArrayEquals(new String[] { "Hi", "there", "nice", "to", "meet", "you" }, myArray);
+    }
+
+    @Test
+    void givenAString_whenSplitToSentenceArray_shouldGetExpectedResult() {
+        String[] myArray = INPUT.split("[-,.!;?]\\s*");
+        assertArrayEquals(new String[] { "Hi there", "nice to meet you" }, myArray);
+    }
+
+    @Test
+    void givenAString_whenSplitToCharArray_shouldGetExpectedResult() {
+        String[] myArray = INPUT.split("");
+        assertArrayEquals(new String[] {
+            "H", "i", " ", "t", "h", "e", "r", "e", ",", " ",
+            "n", "i", "c", "e", " ", "t", "o", " ", "m", "e", "e", "t", " ", "y", "o", "u", "!"
+        }, myArray);
+    }
+
+    @Test
+    void givenAString_whenSpecialRuleRequired_shouldGetExpectedResult() {
+        String dateStr = FLIGHT_INPUT.substring(0, 8);
+        String flightNo = FLIGHT_INPUT.substring(8, FLIGHT_INPUT.length() - 6);
+        int airportStart = dateStr.length() + flightNo.length();
+        String from = FLIGHT_INPUT.substring(airportStart, airportStart + 3);
+        String to = FLIGHT_INPUT.substring(airportStart + 3);
+
+        String[] myArray = new String[] { dateStr, flightNo, from, to };
+        assertArrayEquals(new String[] { "20221018", "LH720", "FRA", "PEK" }, myArray);
+    }
+}