public static String trimToEmpty(String str) {
        return str == null ? EMPTY : str.trim();
    }
<pre>
StringUtils.trimToEmpty(null)          = ""
StringUtils.trimToEmpty("")            = ""
StringUtils.trimToEmpty("     ")       = ""
StringUtils.trimToEmpty("abc")         = "abc"
StringUtils.trimToEmpty("    abc    ") = "abc"
</pre>

@param str the String to be trimmed, may be null
@return the trimmed String, or an empty String if {@code null} input
@since 2.0
core/common/src/main/java/com/alipay/sofa/rpc/common/utils/StringUtils.java