受 Deadbolt“限制”注释影响的 Jackson 解串器

Posted 2023-04-11

【中文标题】受 Deadbolt“限制”注释影响的 Jackson 解串器

【英文标题】：Jackson deserialiser affected by the Deadbolt "restrict" annotation

【发布时间】：2019-05-20 07:56:41

【问题描述】：

当我尝试在带有 @Restrict 注释的路由操作内将 JSON 反序列化为 Map<String, MyClass> 时，我在使用 DeadBolt（2.6.3 和 2.7.0）的 play 2.7 服务器上收到异常 Could not resolve type id 'path.to.MyClass' as a subtype of [simple type, class java.lang.Object]: no such class found。如果删除此注释，一切正常。

MyClass.java

@JsonTypeInfo(use = JsonTypeInfo.Id.CLASS, property = "class")
public class MyClass implements Serializable 
    public String name;
    public Integer age;
    public MyClass()
    public MyClass(String name, Integer age)
        this.name = name;
        this.age = age;
    

序列化Map<String, MyClass>

Map<String, MyClass> value = new HashMap<>();
value.put("first", new MyClass("Bob",10));
value.put("second", new MyClass("Rob",20));

ObjectMapper mapper = Json.newDefaultMapper();
        mapper.enableDefaultTypingAsProperty(ObjectMapper.DefaultTyping.OBJECT_AND_NON_CONCRETE, "class");
String json = null;
try 
    json = mapper.writeValueAsString(value);
 catch (JsonProcessingException e) 
    e.printStackTrace();

输出

  "first":
    "class":"path.to.MyClass",
    "name":"Bob",
    "age":10
  ,
  "second":
    "class":"path.to.MyClass",
    "name":"Rob",
    "age":20
  

JSON 格式看起来如此，因为它向后兼容使用旧 FlexJson 的旧服务器。

反序列化

@Restrict(@Group("Admin"))
public CompletionStage<Result> action(long id) 
    String json = getJsonFromStorage();
    Map<String, MyClass> result = new HashMap<>();
    try 
        ObjectMapper mapper = new ObjectMapper();
        mapper.enableDefaultTypingAsProperty(ObjectMapper.DefaultTyping.OBJECT_AND_NON_CONCRETE, "class");
        JsonFactory factory = mapper.getFactory();
        JsonParser parser = factory.createParser(new ByteArrayInputStream(json.getBytes(Charset.forName("UTF-8"))));
        JavaType type = mapper.getTypeFactory().constructType(result.getClass());
        t = mapper.readValue(parser, type);
         catch (IOException e) 
            e.printStackTrace();
        

    return ok("ok")

【问题讨论】：

类加载器中的问题。如果使用 @Restrict 注释，它会被覆盖。为什么？

Ebean throw java.util.concurrent.CompletionException for Ebean.findNative(clazz, hql).findCount() 和其他类似的 Ebean 请求在有限制的控制器操作中

【参考方案1】：

我有一个临时解决方案。我将当前线程的类加载器从 play.Environment 重写为类加载器

public class MyController extends Controller 

    @Inject
    private Environment environment;

    @Restrict(@Group("Admin"))
    public CompletionStage<Result> action(long id) 

        Thread.currentThread().setContextClassLoader(environment.classLoader());

        String json = getJsonFromStorage();
        Map<String, MyClass> result = new HashMap<>();
        try 
            ObjectMapper mapper = new ObjectMapper();
            mapper.enableDefaultTypingAsProperty(ObjectMapper.DefaultTyping.OBJECT_AND_NON_CONCRETE, "class");
            JsonFactory factory = mapper.getFactory();
            JsonParser parser = factory.createParser(new ByteArrayInputStream(json.getBytes(Charset.forName("UTF-8"))));
            JavaType type = mapper.getTypeFactory().constructType(result.getClass());
            t = mapper.readValue(parser, type);
             catch (IOException e) 
                e.printStackTrace();
            

        return ok("ok")