BAEL-5193 Compare strings while ignoring whitespace (#11455)

* BAEL-5193-compare-strings-ignoring-whitespace

* refactor

* refactor

Co-authored-by: tienvn4 <tienvn4@ghtk.co>

core-java-modules/core-java-string-operations-4/pom.xml

@@ -32,6 +32,16 @@
             <artifactId>opencsv</artifactId>
             <version>${opencsv.version}</version>
         </dependency>
+        <dependency>
+            <groupId>org.springframework</groupId>
+            <artifactId>spring-core</artifactId>
+            <version>${spring-core.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-lang3</artifactId>
+            <version>${apache-commons-lang3.version}</version>
+        </dependency>
     </dependencies>
 
     <build>
@@ -53,6 +63,8 @@
         <assertj.version>3.6.1</assertj.version>
         <guava.version>31.0.1-jre</guava.version>
         <opencsv.version>4.1</opencsv.version>
+        <spring-core.version>5.3.13</spring-core.version>
+        <apache-commons-lang3.version>3.12.0</apache-commons-lang3.version>
     </properties>
 
 </project>

core-java-modules/core-java-string-operations-4/src/test/java/com/baeldung/comparestrings/CompareIgnoreSpacesUnitTest.java

@@ -0,0 +1,28 @@
+package com.baeldung.comparestrings;
+
+import org.apache.commons.lang3.StringUtils;
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+public class CompareIgnoreSpacesUnitTest {
+
+    private static String normalString = "ABCDEF";
+    private static String stringWithSpaces = " AB  CD EF ";
+
+    @Test
+    public void givenTwoStrings_thenCompareWithReplaceAllMethod() {
+        assertEquals(normalString.replaceAll("\\s+",""), stringWithSpaces.replaceAll("\\s+",""));
+    }
+
+    @Test
+    public void givenTwoStrings_thenCompareWithApacheStringUtils() {
+        assertEquals(StringUtils.deleteWhitespace(normalString), StringUtils.deleteWhitespace(stringWithSpaces));
+    }
+
+    @Test
+    public void givenTwoStrings_thenCompareWithSpringStringUtils() {
+        assertEquals(org.springframework.util.StringUtils.trimAllWhitespace(normalString), org.springframework.util.StringUtils.trimAllWhitespace(stringWithSpaces));
+    }
+
+}