后端——》字符串和int转换（StringUtil.safeToString和safeToInteger）

public static boolean isBlank(String str) {
    int strLen;
    if (str == null || (strLen = str.length()) == 0) {
        return true;
    }
    for (int i = 0; i < strLen; i++) {
        if ((Character.isWhitespace(str.charAt(i)) == false)) {
            return false;
        }
    }
    return true;

}

public static String safeToString(Object o, String dv) {
    String r = dv;
    if(o != null) {
        r = String.valueOf(o);
        if(StringUtils.isBlank(r)) {
            r = dv;
        }
    }

    return r;
}

public static Integer safeToInteger(Object o, Integer dv) {
    Integer r = dv;
    if(o != null) {
        try {
            r = new Integer(String.valueOf(o));
        } catch (Exception var4) {
            ;
        }
    }

    return r;
}