java计算过G文件md5 值计算
package io.bigdata;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.security.Provider;
import java.security.Security;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;
import org.apache.commons.codec.digest.DigestUtils;
public class Md5CaculateUtil {
private Md5CaculateUtil(){
}
private static char[] hexChar = {
'0','1','2','3','4','5','6','7','8','9',
'a','b','c','d','e','f'
};
public static String getHash(String fileName,String hashType) throws IOException, NoSuchAlgorithmException{
File f = new File(fileName);
System.out.println(" -------------------------------------------------------------------------------");
System.out.println("|当前文件名称:"+f.getName());
System.out.println("|当前文件大小:"+(f.length()/1024/1024)+"MB");
System.out.println("|当前文件路径[绝对]:"+f.getAbsolutePath());
System.out.println("|当前文件路径[---]:"+f.getCanonicalPath());
System.out.println(" -------------------------------------------------------------------------------");
InputStream ins = new FileInputStream(f);
byte[] buffer = new byte[8192];
MessageDigest md5 = MessageDigest.getInstance(hashType);
int len;
while((len = ins.read(buffer)) != -1){
md5.update(buffer, 0, len);
}
ins.close();
// 也可以用apache自带的计算MD5方法
return DigestUtils.md5Hex(md5.digest());
// 自己写的转计算MD5方法
// return toHexString(md5.digest());
}
public static String getHash2(String fileName){
File f = new File(fileName);
return String.valueOf(f.lastModified());
}
protected static String toHexString(byte[] b){
StringBuilder sb = new StringBuilder(b.length*2);
for(int i=0;i<b.length;i++){
sb.append(hexChar[(b[i] & 0xf0) >>> 4]);
sb.append(hexChar[b[i] & 0x0f]);
}
return sb.toString();
}
/*
* 获取MessageDigest支持几种加密算法
*/
@SuppressWarnings({ "rawtypes", "unchecked" })
private static String[] getCryptolmpls(String serviceType){
Set result = new HashSet();
// all providers
Provider[] providers = Security.getProviders();
for(int i=0;i<providers.length;i++){
// get services provided by each provider
Set keys = providers[i].keySet();
for(Iterator it = keys.iterator();it.hasNext();){
String key = it.next().toString();
key = key.split(" ")[0];
if(key.startsWith(serviceType+".")){
result.add(key.substring(serviceType.length()+1));
}else if(key.startsWith("Alg.Alias."+serviceType+".")){
result.add(key.substring(serviceType.length()+11));
}
}
}
return (String[]) result.toArray(new String[result.size()]);
}
public static void main(String[] args) throws Exception, Exception {
// 调用方法
// String[] names = getCryptolmpls("MessageDigest");
// for(String name:names){
// System.out.println(name);
// }
long start = System.currentTimeMillis();
System.out.println("开始计算文件MD5值,请稍后...");
String fileName = "E:\\Office_2010_Toolkit_2.2.3_XiaZaiBa.zip";
//// String fileName = "E:\\SoTowerStudio-3.1.0.exe";
String hashType = "MD5";
String hash = getHash(fileName,hashType);
System.out.println("MD5:"+hash);
long end = System.currentTimeMillis();
System.out.println("一共耗时:"+(end-start)+"毫秒");
}
}
开始计算文件MD5值,请稍后...
-------------------------------------------------------------------------------
|当前文件名称:Office_2010_Toolkit_2.2.3_XiaZaiBa.zip
|当前文件大小:2437MB
|当前文件路径[绝对]:E:\Office_2010_Toolkit_2.2.3_XiaZaiBa.zip
|当前文件路径[---]:E:\Office_2010_Toolkit_2.2.3_XiaZaiBa.zip
-------------------------------------------------------------------------------
MD5:b1d269391c87942e5bb32b575baa0d79
一共耗时:18794毫秒
