Locale deserialize 'zh-hant_CN'

[takeseem]

zh-hant_CN will convert to zh_HANT_cn

Locale include (language, country, variant), Locale.toString() use '_' to split then {language}_{country}_({variant}_# | #){script}-{extensions}

but Jackson deserialize Locale use '-' or '_' : (
code: LocaleHandle.readResolve()

iana language-tags

zh-Hant	Chinese, in traditional script	[Mark_Davis][Mark_Davis_2]	
zh-Hant-CN	PRC Mainland Chinese in traditional script	[Mark_Davis][Mark_Davis_2]	
zh-Hant-HK	Hong Kong Chinese in traditional script	[Mark_Davis][Mark_Davis_2]	
zh-Hant-MO	Macao Chinese in traditional script	[Mark_Davis][Mark_Davis_2]	
zh-Hant-SG	Singapore Chinese in traditional script	[Mark_Davis][Mark_Davis_2]	
zh-Hant-TW	Taiwan Chinese in traditional script	[Mark_Davis][Mark_Davis_2]

rfc4647 language lookup

  Example of a Lookup Fallback Pattern

   Range to match: zh-Hant-CN-x-private1-private2
   1. zh-Hant-CN-x-private1-private2
   2. zh-Hant-CN-x-private1
   3. zh-Hant-CN
   4. zh-Hant
   5. zh
   6. (default)

	public static void main(String[] args) {
		System.out.println(new Locale("zh-hant", "CN"));
	}

in jdk1.5 -> 1.8

jdk1.5	zh-hant_CN
jdk1.6	zh-hant_CN
jdk1.7	zh-hant_CN
jdk1.8	zh-hant_CN

[beiwei30]

one more comments: if user starts to complain the inter-op compatibility between old dubbo version and current version, we may need to consider to rollback change 0423219, or consider to introduce a system property to control the behavior.

[takeseem]

我优化了代码，英文太差直接中文:(

commit 844d7c7

public class LocaleHandle implements java.io.Serializable, HessianHandle {
    private String value;

    public LocaleHandle(String locale) {
        this.value = locale;
    }

    private Object readResolve() {
        if (value == null) {
            return null;
        }

        if (value.length() == 0) {
            return new Locale("");
        }

        int extStart = value.indexOf("_#");
        if (extStart != -1) value = value.substring(0, extStart);

        String language = value, country = "", variant = "";
        int pos1 = value.indexOf('_');
        if (pos1 != -1) {
            language = value.substring(0, pos1++);

            int pos2 = value.indexOf('_', pos1);
            if (pos2 == -1) {
                country = value.substring(pos1);
            } else {
                country = value.substring(pos1, pos2);
                variant = value.substring(pos2 + 1);
            }
        }
        return new Locale(language, country, variant);
    }
}

[vihunk]

The code's readability needs to improve.

[takeseem]

@vihunk 能否说的更加具体，比如直接在commit 376806a添加：comments。