issue 913修复

[jiangqiang1996]

新增bug修复以及对应测试类。修复集合不可变时反序列化出错的问题。

#913

[wenshao]

单测没跑过，你需要处理下

[jiangqiang1996]

单测没跑过，你需要处理下

貌似有个地方的问题没办法从根本上解决，例如TypeUtils这个类的写法。按照之前的写法，根据className获取它的类型。示例代码：

但是由于jdk高版本新增了一些内置的集合类型，然而fastjson2本身是基于jdk8开发，没办法通过代码获取到高版本具体的Class，也就是我图中圈中的部分，没办法通过java代码去获取。因此，我这里的处理是根据字符串className反射得到Class。如果反射获取失败，则统一返回了 Collections.unmodifiableList(new ArrayList<>()).getClass();

        if (className.startsWith("java.util.ImmutableCollections$")) {
            try {
                return Class.forName(className);
            } catch (ClassNotFoundException e) {
                return CLASS_UNMODIFIABLE_LIST;
            }
        }

下面图中的所有类都是不可变的，新版本新增的，没办法一一判读，所以直接用了上面的方式。

所以fastjson2在运行于jdk9以上版本时，对于集合的处理总会出现些不可预期的类型变化。

[jiangqiang1996]

com.alibaba.fastjson2.issues.Issue312.java
这个类我用之前的版本 单元测试貌似也跑不过。

[jiangqiang1996]

下面是我自己项目写了个测试，输出结果和上面测试结果一致。

[codecov-commenter]

Codecov Report

Base: 70.08% // Head: 71.71% // Increases project coverage by +1.63% 🎉

Coverage data is based on head (4165b43) compared to base (8767345).
Patch coverage: 23.07% of modified lines in pull request are covered.

Additional details and impacted files

@@             Coverage Diff              @@
##               main     #917      +/-   ##
============================================
+ Coverage     70.08%   71.71%   +1.63%     
- Complexity    14990    15376     +386     
============================================
  Files           664      664              
  Lines         67155    67677     +522     
  Branches      14063    14194     +131     
============================================
+ Hits          47063    48535    +1472     
+ Misses        14408    13418     -990     
- Partials       5684     5724      +40     

Impacted Files	Coverage Δ
...on2/reader/FieldReaderCollectionFieldReadOnly.java	80.76% <0.00%> (-6.74%)	⬇️
...n2/reader/FieldReaderCollectionMethodReadOnly.java	71.69% <0.00%> (-2.82%)	⬇️
...ain/java/com/alibaba/fastjson2/util/TypeUtils.java	87.51% <42.85%> (-0.43%)	⬇️
...tible/src/main/java/com/alibaba/fastjson/JSON.java	64.03% <0.00%> (-7.12%)	⬇️
.../src/main/java/com/alibaba/fastjson/JSONArray.java	82.24% <0.00%> (-1.52%)	⬇️
...n/java/com/alibaba/fastjson2/JSONWriterPretty.java	93.07% <0.00%> (-0.73%)	⬇️
...in/java/com/alibaba/fastjson2/JSONWriterUTF16.java	79.91% <0.00%> (-0.71%)	⬇️
...alibaba/fastjson2/reader/ObjectReaderProvider.java	75.76% <0.00%> (-0.43%)	⬇️
...m/alibaba/fastjson2/internal/asm/MethodWriter.java	89.39% <0.00%> (-0.18%)	⬇️
...m/alibaba/fastjson2/benchmark/LargeFile2MTest.java	0.00% <0.00%> (ø)
... and 46 more

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