兑换码（Java）

类似游戏兑换码格式，或者自定义格式的兑换码生成。

支持自定义格式，支持添加对象参数。

package com.krls.simulator;

import org.springframework.util.CollectionUtils;

import java.lang.reflect.Field;
import java.util.*;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class T333 {

    /**
     * 对象转Map
     *
     * @param object
     * @return
     * @throws IllegalAccessException
     */
    public static Map<String, Object> beanToMap(Object object) throws IllegalAccessException {
        if (object instanceof Map) {
            return (Map<String, Object>) object;
        }
        Map<String, Object> map = new HashMap<>(16);
        Field[] fields = object.getClass().getDeclaredFields();
        for (Field field : fields) {
            field.setAccessible(true);
            map.put(field.getName(), field.get(object));
        }
        return map;
    }

    public static String replaceAttr(String str, Object obj) {
        if (obj == null) {
            return str;
        }
        try {
            Map<String, Object> map = beanToMap(obj);
            if (!CollectionUtils.isEmpty(map)) {
                for (Map.Entry<String, Object> entity : map.entrySet()) {
                    String val = entity.getValue() == null ? "" : entity.getValue().toString();
                    str = str.replaceAll("\\$\\{" + entity.getKey() + "}", val);
                }
            }
        } catch (IllegalAccessException e) {

        }
        return str;
    }

    public static String replaceRandom(String source, Map<String, String> map) {
        String reg = "\\[([^.]-[^.])+]\\{[0-9]*}";
        Matcher matcher = Pattern.compile(reg).matcher(source);
        int i = 0;
//        System.out.println(source);
        while (matcher.find()) {
            String group = matcher.group();
            String radius = group.substring(group.indexOf("\\[") + 2, group.indexOf("]"));
            String num = group.substring(group.indexOf("{") + 1, group.indexOf("}"));
            String key = "$" + i + "_" + Integer.parseInt(num);
            map.put(key, getRandomStr(radius));
            source = source.substring(0, source.indexOf(group)) + "$" + i++ + source.substring(source.indexOf(group) + group.length());
        }
        return source;
    }

    public static String getRandomStr(String str) {
        StringBuffer buffer = new StringBuffer();
        for (int i = 0; i < str.length(); i = i + 3) {
            int len = (int) str.charAt(i + 2) - (int) str.charAt(i);
            for (int j = 0; j <= len; j++) {
                buffer.append((char) ((int) str.charAt(i) + j));
            }
        }
        return buffer.toString();
    }

    public static List<String> getRandomStr(String str, int len, int size) {
        Random random = new Random();
        List<String> list = new ArrayList<>();
        StringBuilder cache = new StringBuilder();
        for (int i = 0; i < len * size; i++) {
            int temp = random.nextInt(str.length());
            cache.append(str.charAt(temp));
            if ((i + 1) % len == 0) {
                list.add(cache.toString());
                cache = new StringBuilder();
            }
        }
        return list;
    }

    /**
     * 兑换码生成(V1.0)
     *
     * @param pattern => [0-9A-Z]{4}-[0-9A-Z]{4}-[0-9A-Z]{4}  ${randomNo}-[0-9A-Z]{5}
     * @param obj     => object(id=? name? randomNo?)
     * @param size    =>
     * @return
     */
    public static List<String> getRandomCode(String pattern, Object obj, int size) {
        pattern = replaceAttr(pattern, obj);
        Map<String, String> map = new HashMap<>(16);
        pattern = replaceRandom(pattern, map);
//        size = size > 2 << 4 ? size * 3 / 2 : size << 1;
        Map<Integer, String> result = new HashMap<>(16);
        for (int i = 0; i < size; i++) {
            result.put(i, pattern);
        }
        if (!CollectionUtils.isEmpty(map)) {
            for (Map.Entry<String, String> entry : map.entrySet()) {
                String key = entry.getKey();
                String val = entry.getValue();
                String[] arr = key.split("_");
                List<String> randoms = getRandomStr(val, Integer.parseInt(arr[1]), size);
                for (int i = 0; i < randoms.size(); i++) {
                    result.put(i, result.get(i).replace(arr[0], randoms.get(i)));
                }
            }
        }
        return new ArrayList<>(result.values());
    }
}