BAEL-6804: Difference Between ZipFile and ZipInputStream in Java (#15039)

* BAEL-6804: Difference Between ZipFile and ZipInputStream in Java

* BAEL-6804: Difference Between ZipFile and ZipInputStream in Java
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core-java-modules/core-java-io-5/src/main/java/com/baeldung/zip/ZipBenchmark.java

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+package com.baeldung.zip;
+
+import java.io.*;
+import java.util.concurrent.TimeUnit;
+import java.util.*;
+import java.util.zip.*;
+
+import org.openjdk.jmh.annotations.*;
+import org.openjdk.jmh.infra.Blackhole;
+import org.openjdk.jmh.runner.Runner;
+import org.openjdk.jmh.runner.options.Options;
+import org.openjdk.jmh.runner.options.OptionsBuilder;
+
+@State(Scope.Benchmark)
+@BenchmarkMode(Mode.AverageTime)
+@Warmup(iterations = 1, time = 2, timeUnit = TimeUnit.SECONDS)
+@Measurement(iterations = 3, time = 1, timeUnit = TimeUnit.SECONDS)
+@OutputTimeUnit(TimeUnit.MILLISECONDS)
+@Fork(value = 1)
+public class ZipBenchmark {
+
+    public static final int NUM_OF_FILES = 10;
+    public static final int DATA_SIZE = 204800;
+
+    @State(Scope.Thread)
+    public static class SourceState {
+
+        public File compressedFile;
+
+        @Setup(Level.Trial)
+        public void setup() throws IOException {
+            ZipSampleFileStore sampleFileStore = new ZipSampleFileStore(NUM_OF_FILES, DATA_SIZE);
+            compressedFile = sampleFileStore.getFile();
+        }
+
+        @TearDown(Level.Trial)
+        public void cleanup() {
+            if (compressedFile.exists()) {
+                compressedFile.delete();
+            }
+        }
+    }
+
+    @Benchmark
+    public static void readAllEntriesByZipFile(SourceState sourceState, Blackhole blackhole) throws IOException {
+
+        try (ZipFile zipFile = new ZipFile(sourceState.compressedFile)) {
+            Enumeration<? extends ZipEntry> zipEntries = zipFile.entries();
+            while (zipEntries.hasMoreElements())  {
+                ZipEntry zipEntry = zipEntries.nextElement();
+                try (InputStream inputStream = new BufferedInputStream(zipFile.getInputStream(zipEntry))) {
+                    blackhole.consume(ZipSampleFileStore.getString(inputStream));
+                }
+            }
+        }
+    }
+
+    @Benchmark
+    public static void readAllEntriesByZipInputStream(SourceState sourceState, Blackhole blackhole) throws IOException {
+
+        try (
+            BufferedInputStream bis = new BufferedInputStream(new FileInputStream(sourceState.compressedFile));
+            ZipInputStream zipInputStream = new ZipInputStream(bis)
+        ) {
+            ZipEntry entry;
+            while ((entry = zipInputStream.getNextEntry()) != null) {
+                blackhole.consume(ZipSampleFileStore.getString(zipInputStream));
+            }
+        }
+    }
+
+    @Benchmark
+    public static void readLastEntryByZipFile(SourceState sourceState, Blackhole blackhole) throws IOException {
+
+        try (ZipFile zipFile = new ZipFile(sourceState.compressedFile)) {
+           ZipEntry zipEntry = zipFile.getEntry(getLastEntryName());
+            try (InputStream inputStream = new BufferedInputStream(zipFile.getInputStream(zipEntry))) {
+                blackhole.consume(ZipSampleFileStore.getString(inputStream));
+            }
+        }
+    }
+
+    @Benchmark
+    public static void readLastEntryByZipInputStream(SourceState sourceState, Blackhole blackhole) throws IOException {
+
+        try (
+            BufferedInputStream bis = new BufferedInputStream(new FileInputStream(sourceState.compressedFile));
+            ZipInputStream zipInputStream = new ZipInputStream(bis)
+        ) {
+            ZipEntry entry;
+            while ((entry = zipInputStream.getNextEntry()) != null) {
+                if (Objects.equals(entry.getName(), getLastEntryName())){
+                    blackhole.consume(ZipSampleFileStore.getString(zipInputStream));
+                }
+            }
+        }
+    }
+
+    private static String getLastEntryName() {
+        return String.format(ZipSampleFileStore.ENTRY_NAME_PATTERN, NUM_OF_FILES);
+    }
+
+    public static void main(String[] args) throws Exception {
+        Options options = new OptionsBuilder()
+          .include(ZipBenchmark.class.getSimpleName()).threads(1)
+          .shouldFailOnError(true)
+          .shouldDoGC(true)
+          .jvmArgs("-server").build();
+        new Runner(options).run();
+    }
+
+}

core-java-modules/core-java-io-5/src/main/java/com/baeldung/zip/ZipSampleFileStore.java

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+package com.baeldung.zip;
+
+import java.io.*;
+import java.nio.charset.Charset;
+import java.nio.charset.StandardCharsets;
+import java.util.*;
+import java.util.zip.ZipEntry;
+import java.util.zip.ZipOutputStream;
+
+import org.apache.commons.io.IOUtils;
+
+public class ZipSampleFileStore {
+
+    public static final String ENTRY_NAME_PATTERN = "str-data-%s.txt";
+    private static final Charset DEFAULT_ENCODING = StandardCharsets.UTF_8;
+
+    private final File file;
+    private final List<String> dataList;
+
+    public ZipSampleFileStore(int numOfFiles, int fileSize) throws IOException {
+
+        dataList = new ArrayList<>(numOfFiles);
+        file = File.createTempFile("zip-sample", "");
+
+        try (ZipOutputStream zos = new ZipOutputStream(new FileOutputStream(file))) {
+
+            for (int idx=0; idx<=numOfFiles; idx++) {
+
+                byte[] data = createRandomStringInByte(fileSize);
+                dataList.add(new String(data, DEFAULT_ENCODING));
+
+                ZipEntry entry = new ZipEntry(String.format(ENTRY_NAME_PATTERN, idx));
+                zos.putNextEntry(entry);
+                zos.write(data);
+                zos.closeEntry();
+            }
+        }
+    }
+
+    public static byte[] createRandomStringInByte(int size) {
+        Random random = new Random();
+        byte[] data = new byte[size];
+        for (int n = 0; n < data.length; n++) {
+            char randomChar;
+            int choice = random.nextInt(2); // 0 for uppercase, 1 for lowercase
+            if (choice == 0) {
+                randomChar = (char) ('A' + random.nextInt(26)); // 'A' to 'Z'
+            } else {
+                randomChar = (char) ('a' + random.nextInt(26)); // 'a' to 'z'
+            }
+            data[n] = (byte) randomChar;
+        }
+        return data;
+    }
+
+    public File getFile() {
+        return file;
+    }
+
+    public List<String> getDataList() {
+        return dataList;
+    }
+
+    public static String getString(InputStream inputStream) throws IOException {
+        ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
+        IOUtils.copy(inputStream, byteArrayOutputStream);
+        return byteArrayOutputStream.toString(DEFAULT_ENCODING);
+    }
+
+}