- [x] I have searched the [issues](https://github.com/apache/dubbo/issues) of this repository and believe that this is not a duplicate.
- [x] I have checked the [FAQ](https://github.com/apache/dubbo/blob/master/FAQ.md) of this repository and believe that this is not a duplicate.

### Environment

* Dubbo version: 2.7.4
* Operating System version: Darwin Kernel Version 18.7.0
* Java version: 1.8.0_181-b13)

### Steps to reproduce this issue

1. invoke `StringUtils.split("d,1,2,4", 'a')`
2. invoke `"d,1,2,4".split("a")`

Pls. provide [GitHub address] to reproduce this issue.

### Expected Result

`StringUtils.split("d,1,2,4", 'a')` should return `["d,1,2,4"]` just like `"d,1,2,4".split("a")`.

### Actual Result

empty array.

}
    }
    /**
     * translate.
     *
     * @param src  source string.
     * @param from src char table.
     * @param to   target char table.
     * @return String.
     */
    public static String translate(String src, String from, String to) {
        if (isEmpty(src)) {
            return src;
        }
        StringBuilder sb = null;
        int ix;
        char c;
        for (int i = 0, len = src.length(); i < len; i++) {
            c = src.charAt(i);
            ix = from.indexOf(c);
            if (ix == -1) {
                if (sb != null) {
                    sb.append(c);
                }
            } else {
                if (sb == null) {
                    sb = new StringBuilder(len);
                    sb.append(src, 0, i);
                }
                if (ix < to.length()) {