Now there is the service that zips a list of files

Author: MBenincasa

src/main/java/io/github/mbenincasa/javaexcelutils/model/zip/ZipModel.java

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+package io.github.mbenincasa.javaexcelutils.model.zip;
+
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import lombok.Setter;
+
+/**
+ * This is a model which contains the data of the file to be zipped which is used in {@code ZipUtility}
+ * @author Mirko Benincasa
+ * @since 0.4.2
+ */
+@AllArgsConstructor
+@Getter
+@Setter
+public class ZipModel {
+
+    /**
+     * The Byte array of the file to zip
+     */
+    private byte[] bytes;
+
+    /**
+     * The name of the file to zip
+     */
+    private String filename;
+}

src/main/java/io/github/mbenincasa/javaexcelutils/tools/ZipUtility.java

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+package io.github.mbenincasa.javaexcelutils.tools;
+
+import io.github.mbenincasa.javaexcelutils.model.zip.ZipModel;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.util.List;
+import java.util.zip.ZipEntry;
+import java.util.zip.ZipOutputStream;
+
+/**
+ * {@code ZipUtility} is a static class that provides utility methods for zipped files
+ * @author Mirko Benincasa
+ * @since 0.4.2
+ */
+public class ZipUtility {
+
+    /**
+     * @param zipModels A list of ZipModel objects representing the files to zip
+     * @return The zipped file in the form of a ByteArrayOutputStream
+     * @throws IOException If an I/O error has occurred
+     */
+    public static ByteArrayOutputStream zipFiles(List<ZipModel> zipModels) throws IOException {
+        ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
+        ZipOutputStream zipOutputStream = new ZipOutputStream(byteArrayOutputStream);
+        for (ZipModel zipModel : zipModels) {
+            ZipEntry zipEntry = new ZipEntry(zipModel.getFilename());
+            zipEntry.setSize(zipModel.getBytes().length);
+            zipOutputStream.putNextEntry(zipEntry);
+            zipOutputStream.write(zipModel.getBytes());
+        }
+
+        zipOutputStream.closeEntry();
+        zipOutputStream.close();
+        return byteArrayOutputStream;
+    }
+}

src/test/java/io/github/mbenincasa/javaexcelutils/tools/ZipUtilityTest.java

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+package io.github.mbenincasa.javaexcelutils.tools;
+
+import io.github.mbenincasa.javaexcelutils.model.zip.ZipModel;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+import java.io.*;
+import java.nio.file.Files;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.zip.ZipEntry;
+import java.util.zip.ZipInputStream;
+
+class ZipUtilityTest {
+
+    private final File excelFile = new File("./src/test/resources/employee_2.xlsx");
+    private final File jsonFile = new File("./src/test/resources/office.json");
+
+    @Test
+    void zipFiles() throws IOException {
+        byte[] bytes = Files.readAllBytes(excelFile.toPath());
+        ZipModel zipModel = new ZipModel(bytes, excelFile.getName());
+        byte[] bytes1 = Files.readAllBytes(jsonFile.toPath());
+        ZipModel zipModel1 = new ZipModel(bytes1, jsonFile.getName());
+
+        List<ZipModel> zipModels = new ArrayList<>();
+        zipModels.add(zipModel);
+        zipModels.add(zipModel1);
+        ByteArrayOutputStream byteArrayOutputStream = ZipUtility.zipFiles(zipModels);
+        FileOutputStream fileOutputStream = new FileOutputStream("./src/test/resources/file.zip");
+        fileOutputStream.write(byteArrayOutputStream.toByteArray());
+
+        fileOutputStream.close();
+
+        File file = new File("./src/test/resources/file.zip");
+        FileInputStream fs = new FileInputStream(file);
+        ZipInputStream Zs = new ZipInputStream( new BufferedInputStream(fs));
+
+        ZipEntry ze = Zs.getNextEntry();
+        assert ze != null;
+        Assertions.assertEquals("employee_2.xlsx", ze.getName());
+        ze = Zs.getNextEntry();
+        Assertions.assertEquals("office.json", ze.getName());
+
+        fs.close();
+        file.delete();
+    }
+}