atob解碼

 

前臺js
window.atob();
window.btoa()；
後臺
import java.io.UnsupportedEncodingException;
import java.net.URLDecoder;
import java.net.URLEncoder;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.apache.log4j.Logger;
/**

• @author zxy

• @date 2020年8月24日 上午11:20:16

• @Description : 字符串加密類
  */
  public class BtoAAtoB {

  private static Logger log = Logger.getLogger(“BtoAAtoB.class”);

  private static String base64hash = “ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/”;

  public static boolean isMatcher(String inStr, String reg) {
  Pattern pattern = Pattern.compile(reg);
  Matcher matcher = pattern.matcher(inStr);
  if (matcher.matches()) {
  return true;
  }
  return false;
  }

  /**

  • btoa method

  • @param inStr

  • @return
    */
    public static String btoa(String inStr) {

    if (inStr == null || isMatcher(inStr, “([^\u0000-\u00ff])”)) {
    return null;
    }

    StringBuilder result = new StringBuilder();
    int i = 0;
    int mod = 0;
    int ascii;
    int prev = 0;
    while (i < inStr.length()) {
    ascii = inStr.charAt(i);
    mod = i % 3;
    switch (mod) {
    case 0:
    result.append(String.valueOf(base64hash.charAt(ascii >> 2)));
    break;
    case 1:
    result.append(String.valueOf(base64hash.charAt((prev & 3) << 4 | (ascii >> 4))));
    break;
    case 2:
    result.append(String.valueOf(base64hash.charAt((prev & 0x0f) << 2 | (ascii >> 6))));
    result.append(String.valueOf(base64hash.charAt(ascii & 0x3f)));
    break;
    }
    prev = ascii;
    i++;
    }
    if (mod == 0) {
    result.append(String.valueOf(base64hash.charAt((prev & 3) << 4)));
    result.append("==");
    } else if (mod == 1) {
    result.append(String.valueOf(base64hash.charAt((prev & 0x0f) << 2)));
    result.append("=");
    }
    return result.toString();
    }

/**

• atob method 逆轉encode的思路即可

• @param inStr

• @return
  */
  public static String atob(String inStr) {
  if (inStr == null)
  return null;
  inStr = inStr.replaceAll("\s|=", “”);
  StringBuilder result = new StringBuilder();
  int cur;
  int prev = -1;
  int mod;
  int i = 0;
  while (i < inStr.length()) {
  cur = base64hash.indexOf(inStr.charAt(i));
  mod = i % 4;
  switch (mod) {
  case 0:
  break;
  case 1:
  result.append(String.valueOf((char) (prev << 2 | cur >> 4)));
  break;
  case 2:

   	result.append(String.valueOf((char) ((prev & 0x0f) << 4 | cur >> 2)));break;case 3:result.append(String.valueOf((char) ((prev & 3) << 6 | cur)));break;}prev = cur;i++;
  

  }
  return result.toString();
  }