java语言获取大文件MD5值的实例源码方法介绍，大文件MD5操作实例说明：
package com.topcheer;
import org.apache.commons.codec.binary.Hex;
import org.apache.commons.codec.digest.DigestUtils;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
/**
* 计算大文件MD5
* David 2012-10-12
*/
public class GetBigFileMD5 {
static MessageDigest MD5 = null;
static {
try {
MD5 = MessageDigest.getInstance(“MD5″);
} catch (NoSuchAlgorithmException ne) {
ne.printStackTrace();
}
}
/**
* 对一个文件获取md5值
* @return md5串
*/
public static String getMD5(File file) {
FileInputStream fileInputStream = null;
try {
fileInputStream = new FileInputStream(file);
byte[] buffer = new byte[8192];
int length;
while ((length = fileInputStream.read(buffer)) != -1) {
MD5.update(buffer, 0, length);
}
return new String(Hex.encodeHex(MD5.digest()));
} catch (FileNotFoundException e) {
e.printStackTrace();
return null;
} catch (IOException e) {
e.printStackTrace();
return null;
} finally {
try {
if (fileInputStream != null)
fileInputStream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
/**
* 求一个字符串的md5值
* @param target 字符串
* @return md5 value
*/
public static String MD5(String target) {
return DigestUtils.md5Hex(target);
}
public static void main(String[] args){
long beginTime =System.currentTimeMillis();
File fileZIP = new File(“D:/TEST/IMAGE2.zip”);
String md5=getMD5(fileZIP);
long endTime =System.currentTimeMillis();
System.out.println(“MD5:”+md5+”\n time:”+((endTime-beginTime)/1000)+”s”);
}
}
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