添加520业务支持向redis中存放文件

src/main/java/com/nis/util/MD5Utils.java

@@ -3,81 +3,95 @@
  */
 package com.nis.util;
 
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
 import java.io.FileInputStream;
 import java.io.IOException;
 import java.io.InputStream;
-import java.io.UnsupportedEncodingException;
 import java.security.MessageDigest;
 import java.security.NoSuchAlgorithmException;
-import java.util.List;
-import java.util.Locale;
-import java.util.regex.Matcher;
-import java.util.regex.Pattern;
 
-import javax.servlet.http.HttpServletRequest;
-
-import org.apache.commons.lang3.StringEscapeUtils;
-import org.springframework.web.context.request.RequestContextHolder;
-import org.springframework.web.context.request.ServletRequestAttributes;
-import org.springframework.web.servlet.LocaleResolver;
-
-import com.ckfinder.connector.ServletContextFactory;
-import com.google.common.collect.Lists;
-import com.nis.web.service.SpringContextHolder;
+import org.apache.commons.codec.digest.DigestUtils;
 
 /**
  * 字符串工具类, 继承org.apache.commons.lang3.StringUtils类
  * @author ThinkGem
  * @version 2013-05-22
  */
-public class MD5Utils{
-	
+public class MD5Utils {
+
 	/**
 	 * 字符串转为MD532位小写
 	 * @param plain
 	 * @return
 	 */
-	public static String md5LowerCase(String plain) throws Exception{
+	public static String md5LowerCase(String plain) throws Exception {
 		String re_md5 = new String();
-			MessageDigest md = MessageDigest.getInstance("MD5");
-			md.update(plain.getBytes());
-			byte b[] = md.digest();
-		
-			int i;
-		
-			StringBuffer buf = new StringBuffer("");
-			for (int offset = 0; offset < b.length; offset++) {
+		MessageDigest md = MessageDigest.getInstance("MD5");
+		md.update(plain.getBytes());
+		byte b[] = md.digest();
+
+		int i;
+
+		StringBuffer buf = new StringBuffer("");
+		for (int offset = 0; offset < b.length; offset++) {
 			i = b[offset];
 			if (i < 0)
-			i += 256;
+				i += 256;
 			if (i < 16)
-			buf.append("0");
+				buf.append("0");
 			buf.append(Integer.toHexString(i));
-			}
-			
-			re_md5 = buf.toString();
-			return re_md5;
 		}
-	public static byte[] createChecksum(String filename) throws IOException, NoSuchAlgorithmException{
-		InputStream fis=new FileInputStream(filename);
-		byte[] buffer=new byte[1024];
-		MessageDigest complete=MessageDigest.getInstance("MD5");
+
+		re_md5 = buf.toString();
+		return re_md5;
+	}
+
+	public static byte[] createChecksum(String filename) throws IOException, NoSuchAlgorithmException {
+		InputStream fis = new FileInputStream(filename);
+		byte[] buffer = new byte[1024];
+		MessageDigest complete = MessageDigest.getInstance("MD5");
 		int numRead;
-		do{
-			numRead=fis.read(buffer);
-			if(numRead>0){
-				complete.update(buffer,0,numRead);
+		do {
+			numRead = fis.read(buffer);
+			if (numRead > 0) {
+				complete.update(buffer, 0, numRead);
 			}
-		}while(numRead!=-1);
+		} while (numRead != -1);
 		fis.close();
 		return complete.digest();
 	}
-	public static String getMD5Checksum(String filename) throws NoSuchAlgorithmException, IOException{
-		byte[] b=createChecksum(filename);
-		StringBuffer result=new StringBuffer();
-		for(int i=0;i<b.length;i++){
-			result.append(Integer.toString((b[i] & 0xff)+ 0x100,16).substring(1));
+
+	public static String getMD5Checksum(String filename) throws NoSuchAlgorithmException, IOException {
+		byte[] b = createChecksum(filename);
+		StringBuffer result = new StringBuffer();
+		for (int i = 0; i < b.length; i++) {
+			result.append(Integer.toString((b[i] & 0xff) + 0x100, 16).substring(1));
 		}
 		return result.toString();
 	}
+
+	public static void main(String[] args) throws NoSuchAlgorithmException, IOException {
+		long start1 = System.currentTimeMillis();
+		String md5Checksum = getMd5ByIS(new FileInputStream("f:\\1.iso"));
+		System.out.println(md5Checksum);
+		long start2 = System.currentTimeMillis();
+		System.out.println("第一次用时" + (start2 - start1));
+		String md5Checksum1 = getMD5Checksum("f:\\1.iso");
+		long start3 = System.currentTimeMillis();
+		System.out.println(md5Checksum1);
+		System.out.println("第二次用时" + (start3 - start2));
+
+	}
+
+	/**
+	 * 这种方式计算大文件时更快一些
+	 * @param fis
+	 * @return
+	 * @throws IOException
+	 * @throws NoSuchAlgorithmException
+	 */
+	public static String getMd5ByIS(InputStream is) throws IOException, NoSuchAlgorithmException {
+		return DigestUtils.md5Hex(is);
+	}
 }