encryordecry.java

1.大小写金额转换.java 2.用JAVA程序取得IP地址 3.在Servlet与JSP中取得当前文件所在的相对路径与绝对路径 4.加密解密算法 5.JSP中文乱码.pdf

import java.net.UnknownHostException;
import java.net.InetAddress;
import java.security.SecureRandom;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Random;


public class EncryOrDecry extends Object {


    //加密字符串
    public static String udfEncrypt(String source) {
        if (source == null || source.equals("")) {
            return "";
        }
        String s = "";
        char[] b = source.toCharArray();
        //char[] c = new char[b.length];

        int i1 = 0, i2 = 0, i3 = 0;
        for (int i = 0; i < b.length; i++) {
            i3 = b[i];
            if (i3 < 256) { //普通字符
                i1 = i3 >>> 4;
                i2 = i3 << 4;
                i2 = i2 & 255;
            } else {
                i1 = i3 >>> 8;
                i2 = i3 << 8;
                i2 = i2 & 65535;
            }
            //c[i] = (char) (i2 + i1);
            String a = "0000" + Integer.toHexString(i2 + i1);
            a = a.substring(a.length() - 4, a.length());
            s += a;
            //s += c[i];
        }
        //s = new String(c);
        return s;
    }

    //字符串还原
    public static String udfDecrypt(String source) {
        if (source == null || source.equals("")) {
            return "";
        }
        String s = "";
        //char[] c = source.toCharArray();
        char[] b = new char[source.length() / 4];
        int i = 0, j = 0, i1 = 0, i2 = 0, i3 = 0;
        String a = "";
        while (j < source.length()) {
            a = source.substring(j, j + 4);
            i3 = Integer.valueOf(a, 16).intValue();
            if (i3 < 256) { //普通字符
                i1 = i3 >>> 4;
                i2 = (i3 << 4) & 255;
            } else {
                i1 = i3 >>> 8;
                i2 = (i3 << 8) & 65535;
            }
            b[i] = (char) (i1 + i2);
            j += 4;
            i++;
        }
        s = new String(b);
        return s;
    }


}