java如何查看系统文件md5值

请参考算法
http://www.java2000.net/viewthread.jsp?tid=199import java.security.MessageDigest; public class StrUtil {   private final static String[] hexDigits = { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "a", "b", "c", "d", "e", "f" };   /**
   * 转换字节数组为16进制字串
   *
   * @param b 字节数组
   * @return 16进制字串
   */   public static String byteArrayToHexString(byte[] b) {
    StringBuffer resultSb = new StringBuffer();
    for (int i = 0; i < b.length; i++) {
      resultSb.append(byteToHexString(b[i]));
    }
    return resultSb.toString();
  }   private static String byteToHexString(byte b) {
    int n = b;
    if (n < 0)
      n = 256 + n;
    int d1 = n / 16;
    int d2 = n % 16;
    return hexDigits[d1] + hexDigits[d2];
  }   public static String MD5Encode(String origin) {
    String resultString = null;     try {
      resultString = new String(origin);
      MessageDigest md = MessageDigest.getInstance("MD5");
      resultString = byteArrayToHexString(md.digest(resultString.getBytes()));
    } catch (Exception ex) {     }
    return resultString;
  }   public static void main(String[] args) {
    System.err.println(MD5Encode("a"));
  }
}

呵呵，在网上抄了一段，目前还看不懂．拿来先用了
我还想问问，j2se写服务器保护程序是不是挺重要的,做桌面软件，一点优势都没有．
我看java就写网站挺占优势的呢
前辈们，我说的对吗？
import java.io.*;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.logging.Level;
import java.util.logging.Logger;import com.sun.corba.se.impl.javax.rmi.CORBA.Util;public class MD5 { public static String getMD5(File file) {
System.out.println("FileName: " + file.getName() + " Path: "
+ file.getPath());
FileInputStream fis = null;
try {
MessageDigest md = MessageDigest.getInstance("MD5");
fis = new FileInputStream(file);
byte[] buffer = new byte[8192];
int length = -1;
System.out.println("开始算");
while ((length = fis.read(buffer)) != -1) {
md.update(buffer, 0, length);
}
System.out.println("算完了");
return bytesToString(md.digest());
} catch (IOException ex) {
Logger.getLogger(Util.class.getName()).log(Level.SEVERE, null, ex);
return null;
} catch (NoSuchAlgorithmException ex) {
Logger.getLogger(Util.class.getName()).log(Level.SEVERE, null, ex);
return null;
} finally {
try {
fis.close();
} catch (IOException ex) {
Logger.getLogger(Util.class.getName()).log(Level.SEVERE, null,
ex);
}
}
} public static String bytesToString(byte[] data) {
char hexDigits[] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
'a', 'b', 'c', 'd', 'e', 'f' };
char[] temp = new char[data.length * 2];
for (int i = 0; i < data.length; i++) {
byte b = data[i];
temp[i * 2] = hexDigits[b >>> 4 & 0x0f];
temp[i * 2 + 1] = hexDigits[b & 0x0f];
}
return new String(temp); } public static void main(String[] args) {
MD5 m = new MD5();
File f = new File("C:\\WINDOWS\\dialer.exe");
System.out.println(m.getMD5(f));
String s1 = "93ee04140d60241002da80756a8eda07";
String s2 = "93ee04140d60241002da80756a8eda07";
System.out.println(s1.equals(s2));
}}

关键还是md5如何算，网上有一大堆的例子，典型的md5如下。 public String getMD5(String s) {
char hexDigits[] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
'a', 'b', 'c', 'd', 'e', 'f' };
try {
byte[] strTemp = s.getBytes();
MessageDigest mdTemp = MessageDigest.getInstance("MD5");
mdTemp.update(strTemp);
byte[] md = mdTemp.digest();
int j = md.length;
char str[] = new char[j * 2];
int k = 0;
for (int i = 0; i < j; i++) {
byte byte0 = md[i];
str[k++] = hexDigits[byte0 >>> 4 & 0xf];
str[k++] = hexDigits[byte0 & 0xf];
}
return new String(str);
} catch (Exception e) {
return null;
}
}

照着修改一下，成了下面的import java.io.*;
import java.security.*;
import javax.swing.JFileChooser;public class FileMd5Test {
public static char[] hexChar = { '0', '1', '2', '3', '4', '5', '6', '7',
'8', '9', 'a', 'b', 'c', 'd', 'e', 'f' }; /**
* 打开文件
*
* */
public static String chooseFileOpen(String title) {
JFileChooser chooser = new JFileChooser();
chooser.setDialogTitle(title);
int i = chooser.showOpenDialog(null);
if (i == JFileChooser.APPROVE_OPTION) {
return chooser.getSelectedFile().getAbsolutePath();
} else {
return "";
}
} /**
* hash计算
* */
private String getHash(String fileName, String hashType) throws Exception {
InputStream fis = new FileInputStream(fileName);
byte[] buffer = new byte[1024];
MessageDigest md5 = MessageDigest.getInstance(hashType);
int i = 0;
while ((i = fis.read(buffer)) > 0) {
md5.update(buffer, 0, i);
}
fis.close();
return toHexString(md5.digest());
} /**
* 转换16进制
* */
private String toHexString(byte[] b) {
StringBuffer sb = new StringBuffer(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 new String(sb);
}
/**
* @param fileName 文件名
* @param type hash类型
* @return
*/
public String showHash(String fileName, String type) {
try {
return getHash(fileName, type);
} catch (Exception e) {
e.printStackTrace();
return null;
}
} public static void main(String[] args) throws Exception {
FileMd5Test test = new FileMd5Test();
String fileName = chooseFileOpen("选择一个文件...");
String hashType = "MD5"; // 可以是别的什么东西，SHA1等
System.out.println(fileName + "\n" + hashType + " --> "
+ test.showHash(fileName, hashType));
}
}

csdn这几天太慢了，刷网页都刷不出来，回复一个就没反应了，
NND，太打击我的学习积极性了！

参考这个是java bean实现：http://www.cn-java.com/www1/?action-viewnews-itemid-3414%27/

关键还是md5如何算，网上有一大堆的例子，典型的md5如下。 public String getMD5(String s) {
char hexDigits[] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
'a', 'b', 'c', 'd', 'e', 'f' };
try {
byte[] strTemp = s.getBytes();
MessageDigest mdTemp = MessageDigest.getInstance("MD5");
mdTemp.update(strTemp);
byte[] md = mdTemp.digest();
int j = md.length;
char str[] = new char[j * 2];
int k = 0;
for (int i = 0; i < j; i++) {
byte byte0 = md[i];
str[k++] = hexDigits[byte0 >>> 4 & 0xf];
str[k++] = hexDigits[byte0 & 0xf];
}
return new String(str);
} catch (Exception e) {
return null;
}
}

一个完整一点的实现，根据上面的模板改进了一下，共同学习import java.io.*;
import java.security.*;
import javax.swing.*;public class FileMd5Test {
public static char[] hexChar = { '0', '1', '2', '3', '4', '5', '6', '7',
'8', '9', 'a', 'b', 'c', 'd', 'e', 'f' }; /**
* 打开文件
*
* */
public static String chooseFileOpen(String title) {
JFileChooser chooser = new JFileChooser();
chooser.setDialogTitle(title);
int i = chooser.showOpenDialog(null);
if (i == JFileChooser.APPROVE_OPTION) {
return chooser.getSelectedFile().getAbsolutePath();
} else {
return "";
}
} /**
* hash计算
* */
private String getHash(String fileName, String hashType) throws Exception {
InputStream fis = new FileInputStream(fileName);
byte[] buffer = new byte[1024];
MessageDigest md5 = MessageDigest.getInstance(hashType);
int i = 0;
while ((i = fis.read(buffer)) != -1) {
md5.update(buffer, 0, i);
}
fis.close();
return toHexString(md5.digest());
} /**
* 转换16进制
* */
private String toHexString(byte[] b) {
StringBuffer sb = new StringBuffer(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 new String(sb);
}
/**
* @param fileName 文件名
* @param type hash类型
* @return
*/
public String showHash(String fileName, String type) {
try {
return getHash(fileName, type);
} catch (Exception e) {
e.printStackTrace();
return null;
}
} public static void main(String[] args) throws Exception {
FileMd5Test test = new FileMd5Test();
String fileName = chooseFileOpen("选择一个文件...");
String hashType = "MD5"; // 可以是别的什么东西，SHA1等
System.out.println(fileName + "\n" + hashType + " --> "
+ test.showHash(fileName, hashType)); }
}

－－－－－－－－－－－－－－
哇哇，前辈的回复我看不到呢
现在就能看到１４　１３　１２　１１楼的帖子
－－－－－－－－－－－－－－
杀毒软件不是一个人能完成的吧，况且现在优秀的杀软也很多。
我就是想把j2se的重点放在写网站服务器保护程序，网站日志分析这样的程序上
java不是擅长做网站吗

调试易

java如何查看系统文件md5值

解决方案 »