java - 如何在 jackson 2.9.x 中禁用 0/1 到 true/false 的转换

Question

我有一个项目需要严格的 json 策略。

例子:

public class Foo {
    private boolean test;

    ... setters/getters ...
}

以下 json 应该可以工作:

{
    test: true
}

下面应该失败(抛出异常):

{
    test: 1
}

同样适用于:

{
    test: "1"
}

基本上，如果有人提供不同于 true 或 false 的内容，我希望反序列化失败。不幸的是，jackson 将 1 视为 true，将 0 视为 false。我找不到禁用该奇怪行为的反序列化功能。

Answer 1

可以禁用 MapperFeature.ALLOW_COERCION_OF_SCALARS 来自 docs

Feature that determines whether coercions from secondary representations are allowed for simple non-textual scalar types: numbers and booleans.

如果您还希望它适用于null，请启用DeserializationFeature.FAIL_ON_NULL_FOR_PRIMITIVES ( More Info )

ObjectMapper mapper = new ObjectMapper();

//prevent any type as boolean
mapper.disable(MapperFeature.ALLOW_COERCION_OF_SCALARS);

// prevent null as false 
// mapper.enable(DeserializationFeature.FAIL_ON_NULL_FOR_PRIMITIVES);

System.out.println(mapper.readValue("{\"test\": true}", Foo.class));
System.out.println(mapper.readValue( "{\"test\": 1}", Foo.class));

结果:

 Foo{test=true} 

 Exception in thread "main"
 com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot
 coerce Number (1) for type `boolean` (enable
 `MapperFeature.ALLOW_COERCION_OF_SCALARS` to allow)  at [Source:
 (String)"{"test": 1}"; line: 1, column: 10] (through reference chain:
 Main2$Foo["test"])