字符串自然排序

package com.***.util;

import java.util.Comparator;
import java.util.HashMap;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * 字符串中连续的大写数字、小写数字作为一个整体进行比较
 * 例如：负二，负1，一，二，一十一，22，211...
 */
public class StringComparator implements Comparator<String> {

    /**
     * @param str1
     * @param str2
     * @return a negative integer, zero, or a positive integer as the
     * first argument is less than, equal to, or greater than the second.
     */
    @Override
    public int compare(String str1, String str2) {
        int n1 = str1.length();
        int n2 = str2.length();
        for (int i1 = 0, i2 = 0; i1 < n1 && i2 < n2; ) {
            NextItem item1 = getNextItem(str1, i1);
            NextItem item2 = getNextItem(str2, i2);
            boolean compared = false;
            int flag = 0;
            if (item1 != null && item2 != null) {
                if (item1.isNum && item2.isNum) {
                    try {
                        flag = Integer.parseInt(item1.value) - Integer.parseInt(item2.value);
                    } catch (NumberFormatException e) {
                        e.printStackTrace();
                        flag = item1.value.compareTo(item2.value);
                    }
                    compared = true;
                } else if (item1.isNum) {
                    return -1;
                } else if (item2.isNum) {
                    return 1;
                } else {
                    flag = item1.value.compareTo(item2.value);
                    compared = true;
                }
            } else if (item1 == null) {
                return -1;
            } else if (item2 == null) {
                return 1;
            }

            if (compared) {
                if (flag == 0) {
                    i1 = item1.nextIndex;
                    i2 = item2.nextIndex;
                    if (i1 >= n1 && i2 >= n2) {
                        return str1.compareTo(str2);
                    } else if (i1 >= n1) {
                        return -1;
                    } else if (i2 >= n2) {
                        return 1;
                    }
                } else {
                    return flag;
                }
            }
        }
        return 0;
    }

    /**
     * 查找连续字符的数字
     *
     * @param str
     * @param index 开始查找位置
     * @return
     */
    private NextItem getNextItem(String str, int index) {
        if (index >= str.length()) {
            return null;
        }
        boolean isNum = false;
        int nextIndex = index + 1;
        String value = str.substring(index, nextIndex);
        Pattern pattern = Pattern.compile("负?\\d+|负?[一二三四五六七八九][零一二三四五六七八九十百千万]*");
        Matcher matcher = pattern.matcher(str);
        if (matcher.find(index)) {
            int start = matcher.start();
            if (start == index) {
                nextIndex = matcher.end();
                value = str.substring(start, nextIndex);
                value = getNumStr(value);
                isNum = true;
            }
        }
        return new NextItem(value, isNum, nextIndex);
    }

    private String getNumStr(String str) {
        StringBuilder sb = new StringBuilder();
        int n = str.length();
        for (int i = 0; i < n; i++) {
            String value = str.substring(i, i + 1);
            if (NumMap.containsKey(value)) {
                value = NumMap.get(value);
            }
            sb.append(value);
        }
        return sb.toString();
    }

    public static final Map<String, String> NumMap = new HashMap<String, String>() {
        {
            String str1 = "负零一二三四五六七八九十百千万";
            String str2 = "-0123456789    ";
            int n1 = str1.length();
            for (int i = 0; i < n1; i++) {
                this.put(str1.substring(i, i + 1), str2.substring(i, i + 1).trim());
            }
        }
    };

    private static class NextItem {
        private String value;  //值
        private boolean isNum; //是否数字
        private int nextIndex; //下一个开始位置

        private NextItem(String value, boolean isNum, int nextIndex) {
            this.value = value;
            this.isNum = isNum;
            this.nextIndex = nextIndex;
        }

        public String toString() {
            return value + "," + isNum + "," + nextIndex;
        }
    }

}