Add files via upload

Author: kevin0016

encryptionUtils/MD5Util.java

@@ -0,0 +1,97 @@
+package encryptionUtils;
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.nio.MappedByteBuffer;
+import java.nio.channels.FileChannel;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+
+
+public class MD5Util {
+	
+	protected static char hexDigits[] = { '0', '1', '2', '3', '4', '5', '6',
+			'7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };
+
+	protected static MessageDigest messagedigest = null;
+
+	static {
+		try {
+			messagedigest = MessageDigest.getInstance("MD5");
+		} catch (NoSuchAlgorithmException e) {
+			e.printStackTrace();
+			messagedigest = null;
+		}
+	}
+
+	public static String getFileMD5String(File file) {
+		String ret = null;
+		if (messagedigest != null) {
+			FileInputStream in = null;
+			FileChannel ch = null;
+			try {
+				in = new FileInputStream(file);
+				ch = in.getChannel();
+				MappedByteBuffer byteBuffer = ch.map(
+						FileChannel.MapMode.READ_ONLY, 0, file.length());
+				messagedigest.update(byteBuffer);
+			} catch (Exception e) {
+				throw new RuntimeException(e);
+			} finally {
+				if (in != null) {
+					try {
+						in.close();
+					} catch (Exception e) {
+						
+						e.printStackTrace();
+					}
+				}
+				if (ch != null) {
+					try {
+						ch.close();
+					} catch (Exception e) {
+						
+						e.printStackTrace();
+					}
+				}
+			}
+			ret = bufferToHex(messagedigest.digest());
+		}
+
+		return ret;
+	}
+
+	public static String getMD5String(String s) {
+		return getMD5String(s.getBytes());
+	}
+
+	public static String getMD5String(byte[] bytes) {
+		String bufferToHex = null;
+		if (messagedigest != null) {
+			messagedigest.update(bytes);
+			bufferToHex = bufferToHex(messagedigest.digest());
+		}
+
+		return bufferToHex;
+	}
+
+	private static String bufferToHex(byte bytes[]) {
+		return bufferToHex(bytes, 0, bytes.length);
+	}
+
+	private static String bufferToHex(byte bytes[], int m, int n) {
+		StringBuffer stringbuffer = new StringBuffer(2 * n);
+		int k = m + n;
+		for (int l = m; l < k; l++) {
+			appendHexPair(bytes[l], stringbuffer);
+		}
+		return stringbuffer.toString();
+	}
+
+	private static void appendHexPair(byte bt, StringBuffer stringbuffer) {
+		char c0 = hexDigits[(bt & 0xf0) >> 4];
+		char c1 = hexDigits[bt & 0xf];
+		stringbuffer.append(c0);
+		stringbuffer.append(c1);
+	}
+}

encryptionUtils/UtilsTest.java

@@ -0,0 +1,12 @@
+package encryptionUtils;
+
+import org.junit.Test;
+
+public class UtilsTest {
+    @Test
+    public void md5Test() throws Exception {
+        String content = "hello World";
+        String md5String = MD5Util.getMD5String(content);
+        System.out.println(md5String);
+    }
+}