文件hash算法速度比较

java/demo/src/main/java/org/zhaodj/util/FileHasher.java

@@ -0,0 +1,62 @@
+package org.zhaodj.util;
+
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+
+public class FileHasher {
+
+	private static final char[] DIGITS = {
+        '0', '1', '2', '3', '4', '5', '6', '7',
+           '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'
+    };
+
+	public static String hash(String algorithm,String filepath) throws NoSuchAlgorithmException, IOException{
+		MessageDigest md=MessageDigest.getInstance(algorithm);
+		InputStream is=new FileInputStream(filepath);
+		int numRead=0;
+		byte[] buffer=new byte[1024];
+		while((numRead=is.read(buffer))>0){
+			md.update(buffer, 0, numRead);
+		}
+		is.close();
+		return new String(encodeHex(md.digest()));
+	}
+
+	public static char[] encodeHex(byte[] data) {
+
+        int l = data.length;
+
+           char[] out = new char[l << 1];
+
+           // two characters form the hex value.
+           for (int i = 0, j = 0; i < l; i++) {
+               out[j++] = DIGITS[(0xF0 & data[i]) >>> 4 ];
+               out[j++] = DIGITS[ 0x0F & data[i] ];
+           }
+
+           return out;
+    }
+
+	public static void test(String algorithm,String filepath,int times) throws NoSuchAlgorithmException, IOException{
+		long begin=System.nanoTime();
+		for(int i=0;i<times;i++){
+			hash(algorithm,filepath);
+		}
+		System.out.println(algorithm+":"+(System.nanoTime()-begin));
+	}
+
+	public static void main(String[] args) throws NoSuchAlgorithmException, IOException{
+		String file="/home/zhaodj/图片/照片/IMG_3643.JPG";
+		System.out.println("file:"+file);
+		test("MD5",file,1000);
+		test("SHA1",file,1000);
+		file="/home/zhaodj/图片/照片/ada.jpg";
+		System.out.println("file:"+file);
+		test("MD5",file,1000);
+		test("SHA1",file,1000);
+	}
+
+}