java 实现md5加密
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;


public class MD4 {
private static String Md5(String plainText ) {

try {
MessageDigest md = MessageDigest.getInstance("MD5");
md.update(plainText.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;
if(i<16)
buf.append("0");
buf.append(Integer.toHexString(i));
}

String result=buf.toString();//32位的加密

System.out.println("result: " + buf.toString().substring(8,24));//16位的加密


return result;
} catch (NoSuchAlgorithmException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return plainText;
}
public static void main(String[] args) {
String tt="lisi321";
System.out.println(Md5(tt));

}

}