[KTLN-865] Create a Zip file in Kotlin (#941)

* unit tests added

* code fixes

* Update core-kotlin-modules/core-kotlin-files/src/test/kotlin/com/baeldung/createZip/CreateZipFileUnitTest.kt

---------

Co-authored-by: Brandon Ward <[email protected]>

Author: albertache1998

core-kotlin-modules/core-kotlin-files/pom.xml

@@ -13,4 +13,19 @@
         <version>1.0.0-SNAPSHOT</version>
     </parent>
 
+    <dependencies>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-compress</artifactId>
+            <version>1.21</version>
+        </dependency>
+
+        <dependency>
+            <groupId>net.lingala.zip4j</groupId>
+            <artifactId>zip4j</artifactId>
+            <version>2.8.0</version>
+        </dependency>
+
+    </dependencies>
+
 </project>

core-kotlin-modules/core-kotlin-files/src/test/kotlin/com/baeldung/createZip/CreateZipFileUnitTest.kt

@@ -0,0 +1,94 @@
+package com.baeldung.createZip
+
+import net.lingala.zip4j.ZipFile
+import net.lingala.zip4j.model.ZipParameters
+import net.lingala.zip4j.model.enums.CompressionLevel
+import net.lingala.zip4j.model.enums.CompressionMethod
+import org.apache.commons.compress.archivers.zip.ZipArchiveEntry
+import org.apache.commons.compress.archivers.zip.ZipArchiveOutputStream
+import org.apache.commons.compress.utils.IOUtils
+import org.junit.jupiter.api.Assertions.assertTrue
+import org.junit.jupiter.api.Test
+import java.io.File
+import java.io.FileInputStream
+import java.io.FileOutputStream
+import java.util.zip.ZipEntry
+import java.util.zip.ZipOutputStream
+
+class CreateZipFileUnitTest {
+
+    val filesToZip = listOf(File("file1.txt").apply { writeText("Hello, World!") }, File("file2.txt").apply { writeText("Kotlin ZIP Test") })
+
+    @Test
+    fun `create  zip file with java standard library`() {
+        val outputZipFile = File("test_output.zip")
+
+        createZipFile(filesToZip, outputZipFile)
+
+        assertTrue(outputZipFile.exists())
+        assertTrue(outputZipFile.length() > 0)
+
+        filesToZip.forEach { it.delete() }
+        outputZipFile.delete()
+    }
+
+    @Test
+    fun `create zip file with apache commons compress`() {
+        val outputZipFile = File("test_output_with_apache.zip")
+
+        createZipFileWithApache(filesToZip, outputZipFile)
+
+        assertTrue(outputZipFile.exists())
+        assertTrue(outputZipFile.length() > 0)
+
+        // Clean up
+        filesToZip.forEach { it.delete() }
+        outputZipFile.delete()
+    }
+
+    @Test
+    fun `create zip file with Zip4j library`() {
+        val outputZipFile = File("test_output_with_zip4j.zip")
+
+        createZipFileWithZip4j(filesToZip, outputZipFile)
+
+        assertTrue(outputZipFile.exists())
+        assertTrue(outputZipFile.length() > 0)
+
+        filesToZip.forEach { it.delete() }
+        outputZipFile.delete()
+    }
+}
+fun createZipFile(files: List<File>, outputZipFile: File) {
+    ZipOutputStream(FileOutputStream(outputZipFile)).use { zipOut ->
+        files.forEach { file ->
+            FileInputStream(file).use { fis ->
+                val zipEntry = ZipEntry(file.name)
+                zipOut.putNextEntry(zipEntry)
+                fis.copyTo(zipOut)
+                zipOut.closeEntry()
+            }
+        }
+    }
+}
+
+fun createZipFileWithApache(files: List<File>, outputZipFile: File) {
+    ZipArchiveOutputStream(FileOutputStream(outputZipFile)).use { zipOut ->
+        files.forEach { file ->
+            zipOut.putArchiveEntry(ZipArchiveEntry(file.name))
+            FileInputStream(file).use { fis ->
+                IOUtils.copy(fis, zipOut)
+            }
+            zipOut.closeArchiveEntry()
+        }
+    }
+}
+
+fun createZipFileWithZip4j(files: List<File>, outputZipFile: File) {
+    val zipFile = ZipFile(outputZipFile)
+    val parameters = ZipParameters().apply {
+        compressionMethod = CompressionMethod.DEFLATE
+        compressionLevel = CompressionLevel.NORMAL
+    }
+    zipFile.addFiles(files, parameters)
+}