java使用md5對數據進行加密，具體方法如下：

package com.ow.util;
import java.security.MessageDigest;
//MD5加密解密
public class MD5Util {
public static String string2MD5(String inStr){
MessageDigest md5 = null;
try{
md5 = MessageDigest.getInstance("MD5");
}catch (Exception e){
System.out.println(e.toString());
e.printStackTrace();
return "";
}
char[] charArray = inStr.toCharArray();
byte[] byteArray = new byte[charArray.length];
for (int i = 0; i < charArray.length; i++)
byteArray[i] = (byte) charArray[i];
byte[] md5Bytes = md5.digest(byteArray);
StringBuffer hexValue = new StringBuffer();
for (int i = 0; i < md5Bytes.length; i++){
int val = ((int) md5Bytes[i]) & 0xff;
if (val < 16)
hexValue.append("0");
hexValue.append(Integer.toHexString(val));
}
return hexValue.toString();
}
public static String MD5Test(String inStr){
String xy = "xy";
String finalStr="";
if(inStr!=null){
String fStr = inStr.substring(0, 1);
String lStr = inStr.substring(1, inStr.length());
finalStr = string2MD5( fStr+xy+lStr);
}else{
finalStr = string2MD5(xy);
}
return finalStr;
}
// 測試
public static void main(String args[]) {
String s1 = "zhang";
System.out.println("使用工具類進行加密的為 "+MD5Test(s1));
}
}