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crypto/How to Compute Hash Code of Streams/pom.xml

@@ -4,10 +4,10 @@
 	<modelVersion>4.0.0</modelVersion>
 
 	<groupId>com.javacreed.examples</groupId>
-	<artifactId>how-to-compute-hash-code-of-large-files</artifactId>
+	<artifactId>how-to-compute-hash-code-of-streams</artifactId>
 	<version>0.0.1-SNAPSHOT</version>
 
-	<name>How to Compute Hash Code of Large Files</name>
+	<name>How to Compute Hash Code of Streams</name>
 	<url>http://www.javacreed.com/${project.artifactId}/</url>
 	<inceptionYear>${project.inceptionYear}</inceptionYear>
 	<organization>

crypto/How to Compute Hash Code of Streams/src/main/java/com/javacreed/examples/crypto/Example.java

@@ -0,0 +1,54 @@
+/*
+ * #%L
+ * How to Compute Hash Code of Streams
+ * $Id:$
+ * $HeadURL:$
+ * %%
+ * Copyright (C) 2012 - 2015 Java Creed
+ * %%
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * 
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * #L%
+ */
+package com.javacreed.examples.crypto;
+
+import java.io.BufferedInputStream;
+import java.net.URL;
+import java.security.DigestInputStream;
+import java.security.MessageDigest;
+import java.util.Formatter;
+
+public class Example {
+  public static void main(final String[] args) throws Exception {
+
+    final URL link = new URL("http://www.javacreed.com/");
+    try (DigestInputStream in = new DigestInputStream(new BufferedInputStream(link.openStream()),
+        MessageDigest.getInstance("SHA-1"))) {
+      // Read the stream and do nothing with it
+      while (in.read() != -1) {}
+
+      // Get the digest and finialise the computation
+      final MessageDigest md = in.getMessageDigest();
+      final byte[] digest = md.digest();
+
+      // Format as HEX
+      try (Formatter formatter = new Formatter()) {
+        for (final byte b : digest) {
+          formatter.format("%02x", b);
+        }
+
+        final String sha1 = formatter.toString();
+        System.out.println(sha1);
+      }
+    }
+  }
+}