iluwatar#2 Add zip multiple files snippet

Author: iluwatar

README.md

@@ -22,6 +22,7 @@ Update the sample application with the snippet and add a test for it. After prov
 * [List files in directory recursively](#list-files-in-directory-recursively)
 * [Read lines from file to string list](#read-lines-from-file-to-string-list)
 * [Zip file](#zip-file)
+* [Zip multiple files](#zip-multiple-files)
 
 ### Math
 * [Factorial](#factorial)
@@ -182,6 +183,30 @@ Update the sample application with the snippet and add a test for it. After prov
     }
 ```
 
+### Zip multiple files
+
+```java
+    public static void zipFiles(String[] srcFilenames, String zipFilename) throws IOException {
+        try (
+            FileOutputStream fileOut = new FileOutputStream(zipFilename);
+            ZipOutputStream zipOut = new ZipOutputStream(fileOut);
+        ) {
+            for (int i=0; i<srcFilenames.length; i++) {
+                File srcFile = new File(srcFilenames[i]);
+                try (FileInputStream fileIn = new FileInputStream(srcFile)) {
+                    ZipEntry zipEntry = new ZipEntry(srcFile.getName());
+                    zipOut.putNextEntry(zipEntry);
+                    final byte[] bytes = new byte[1024];
+                    int length;
+                    while ((length = fileIn.read(bytes)) >= 0) {
+                        zipOut.write(bytes, 0, length);
+                    }
+                }
+            }
+        }
+    }
+```
+
 [⬆ back to top](#table-of-contents)
 
 ## Math

src/main/java/Library.java

@@ -243,6 +243,32 @@ public static void zipFile(String srcFilename, String zipFilename) throws IOExce
         }
     }
 
+    /**
+     * Zip multiples files
+     * @param srcFilenames array of source file names
+     * @param zipFilename the filename of the destination zip file
+     * @throws IOException
+     */
+    public static void zipFiles(String[] srcFilenames, String zipFilename) throws IOException {
+        try (
+            FileOutputStream fileOut = new FileOutputStream(zipFilename);
+            ZipOutputStream zipOut = new ZipOutputStream(fileOut);
+        ) {
+            for (int i=0; i<srcFilenames.length; i++) {
+                File srcFile = new File(srcFilenames[i]);
+                try (FileInputStream fileIn = new FileInputStream(srcFile)) {
+                    ZipEntry zipEntry = new ZipEntry(srcFile.getName());
+                    zipOut.putNextEntry(zipEntry);
+                    final byte[] bytes = new byte[1024];
+                    int length;
+                    while ((length = fileIn.read(bytes)) >= 0) {
+                        zipOut.write(bytes, 0, length);
+                    }
+                }
+            }
+        }
+    }
+
     /**
      * Sort an array with quicksort algorithm
      * @param arr array to sort

src/test/java/LibraryTest.java

@@ -195,8 +195,9 @@ public void testIsPalindrome() {
     @Test
     public void testListFilesInDirectory() {
         File[] files = Library.listFilesInDirectory(new File("src/test/resources"));
-        assertEquals(1, files.length);
+        assertEquals(2, files.length);
         assertEquals("src/test/resources/somelines.txt", files[0].toString());
+        assertEquals("src/test/resources/someotherlines.txt", files[1].toString());
     }
 
     /**
@@ -205,7 +206,7 @@ public void testListFilesInDirectory() {
     @Test
     public void testListAllFiles() {
         List<File> files = Library.listAllFiles("src/test/resources");
-        assertEquals(3, files.size());
+        assertEquals(4, files.size());
     }
 
     /**
@@ -238,6 +239,21 @@ public void testZipFile() throws IOException {
         }
     }
 
+    /**
+     * Tests for {@link Library#zipFiles(String[], String)}
+     */
+    @Test
+    public void testZipFiles() throws IOException {
+        final String[] srcFilenames = {"src/test/resources/somelines.txt", "src/test/resources/someotherlines.txt"};
+        final String dst = "src/test/resources/multiple.zip";
+        try {
+            Library.zipFiles(srcFilenames, dst);
+            assertTrue(Files.exists(Paths.get(dst)));
+        } finally {
+            Files.deleteIfExists(new File(dst).toPath());
+        }
+    }
+
     /**
      * Tests for {@link Library#quickSort(int[], int, int)}
      */

src/test/resources/someotherlines.txt

@@ -0,0 +1,2 @@
+123
+XYZ