[Enhancement] Inconsistent string validation in ProxyConfig.initData() may cause misleading exceptions.

[Kris20030907]

Before Creating the Enhancement Request

• I have confirmed that this should be classified as an enhancement rather than a bug/feature.

Summary

When initializing ProxyConfig, if localServeAddr is mistakenly set to a few empty characters by the user, such as localServerAddr=" ", it will cause an exception 'get local serve ip failed' to be thrown. The real reason is simply a configuration error, which can mislead troubleshooting.

Motivation

enhance config check

Describe the Solution You'd Like

Uniformly use the isBlanck method, which supports checking for null and a length of 0, and can completely replace the isEmpty method.

Describe Alternatives You've Considered

A clearer way to write:

if (StringUtils.isBlank(localServeAddr)) {
        this.localServeAddr = NetworkUtil.getLocalAddress();
        if (StringUtils.isBlank(localServeAddr)) {
            throw new ProxyException(ProxyExceptionCode.INTERNAL_SERVER_ERROR, 
                                   "failed to get local IP address");
        }
    }

Additional Context

detail:

• config:

localServeAddr=    # has several blank char
or
localServeAddr=\t

• config init logic

private String localServeAddr = "   ";  // from config file

if (StringUtils.isEmpty(localServeAddr)) {  // false! "   ".length() > 0 and != null
    // skip, failed to retrieve the local address
}
if (StringUtils.isBlank(localServeAddr)) {   // true!
    throw new ProxyException(...);  // Throws an exception
}

This may lead the user to mistakenly believe there is a network issue.