public String next() {
        if (maxLen <= 0 || minLen <= 0 || minLen > maxLen)
            return null;
        char[] buf = new char[R.random(minLen, maxLen)];
        for (int i = 0; i < buf.length; i++)
            buf[i] = CharGenerator.next();
        return new String(buf);
    }
public String next() {
        if (maxLen <= 0 || minLen <= 0 || minLen > maxLen)
            return null;
        char[] buf = new char[R.random(minLen, maxLen)];
        for (int i = 0; i < buf.length; i++)
            buf[i] = CharGenerator.next();
        return new String(buf);
    }
public String next ( ) { if ( maxLen <= 0 || minLen <= 0 || minLen > maxLen ) return null ; char [ ] buf = new char [ R . random ( minLen , maxLen ) ] ; for ( int i = 0 ; i < buf . length ; i ++ ) buf [ i ] = CharGenerator . next ( ) ; return new String ( buf ) ; }
根据设置的max和min的长度,生成随机字符串.
<p/>
若max或min小于0,则返回null

@return 生成的字符串
根据设置的max和min的长度 生成随机字符串 . <p / > 若max或min小于0 则返回null