修改 DateCodec 判断 dateFormat 长度的逻辑

[vdiskg]

#3361
修改 DateCodec 判断 dateFormat 长度的逻辑，以解决 dateFormatPattern 当中含有 [单引号、Z ] 等导致的长度判断错误

[CLAassistant]

All committers have signed the CLA.

[codecov-commenter]

Codecov Report

Merging #3362 into master will decrease coverage by 0.00%.
The diff coverage is 87.50%.

@@             Coverage Diff              @@
##             master    #3362      +/-   ##
============================================
- Coverage     80.47%   80.46%   -0.01%     
  Complexity     7454     7454              
============================================
  Files           157      157              
  Lines         27840    27847       +7     
  Branches       6708     6708              
============================================
+ Hits          22404    22408       +4     
- Misses         3423     3425       +2     
- Partials       2013     2014       +1     

Impacted Files	Coverage Δ	Complexity Δ
...com/alibaba/fastjson/parser/DefaultJSONParser.java	87.96% <85.71%> (-0.02%)	323.00 <1.00> (+1.00)	⬇️
...ava/com/alibaba/fastjson/serializer/DateCodec.java	92.89% <100.00%> (+0.50%)	50.00 <0.00> (ø)
...com/alibaba/fastjson/serializer/SerialContext.java	82.69% <0.00%> (-3.85%)	21.00% <0.00%> (-1.00%)
...main/java/com/alibaba/fastjson/util/FieldInfo.java	86.62% <0.00%> (-0.34%)	99.00% <0.00%> (ø%)

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[ZivYan]

你这样不是线程安全的诶，其实从全局角度来说我觉得还是在字段上面定义格式会更香一点

[vdiskg]

你这样不是线程安全的诶，其实从全局角度来说我觉得还是在字段上面定义格式会更香一点

我认为全局的格式应当是在初始化阶段设置的，运行期间不应该去改这个值，test里面这么做仅仅是为了验证一下这两种情况都能正确处理而已，实际使用的时候肯定是定死一个值再也不会去改它的。