当类包含接口类型的变量时，如何通过jackson进行序列化/反序列化？

Question

@JsonTypeInfo(use = JsonTypeInfo.Id.Class, include = JsonTypeInfo.As.Property, property = "className")

@JsonSubType({
 @Type(value = abstractClass.class, name = "abstractClass"),
 @Type(value = subClass1.class, name = "subClass1"),
 @Type(value = subClass2.class, name = "subClass2"),
 '
 '
 '
})
interface A {
 func1();
 func2();
}

abstract class abstractClass implements A {
 int abstractvar1;
 func1(){//code} 
}

class subClass1 extends abstractClass {
  int var1;
  int var2;
  A var3;
  A var4;
}

class subClass2 extends abstractClass {
  int var1;
  int var2;
  A var3;
}

class subClass3 extends abstractClass {
  float var1;
  int var2;
  A var3;
}

 and more classes defined trying to extend abstractClass..

class Implementor {
 int implementorVar1;
 String implementorVar2;
 A implementorVar3;
 int implementorVar4;
}

{
  "implementorVar1": 1,
  "implementorVar2": "hello",
  "implementorVar3": {
    "className": "subClass2",
    "abstractVar1": 45,
  },
  "implementorVar4": 1000
}

{
  "implementorVar1": 1,
  "implementorVar2": "hello",
  "implementorVar3": {
    "className": "subClass2",
    "abstractVar1" : 45,
    "var1": 45,
    "var2": 56,
    "var3": {
      "className": "subClass3",
      "var1": 2,
      "var2": 5,
      "var3" : {
        "className" : "" ...
     }
    }
  },
  "implementorVar4": 1000
}

Answer 1

我复制了您的代码与一些变化，它为我工作时，实现如下（序列化和反序列化），所以让我知道这是否符合您的期望。需要注意的要点是对注释的几个小修改，我发现在默认配置中，拥有正确的getter和setter绝对至关重要，否则属性将不会被序列化--这似乎是最可能的问题。

就我个人而言，我会考虑使用配置来允许Jackson直接使用属性，因为我讨厌那些公开泄露你所有内心状态而不是封装它并暴露特定行为的毯子获取器和设置器，但这只是观点--与你的问题无关！

产出：

{
  "implementorVar1" : 1,
  "implementorVar2" : "hello",
  "implementorVar3" : {
    "className" : "subClass2",
    "var1" : 1,
    "var2" : 2,
    "var3" : {
      "className" : "subClass3",
      "var1" : 1.0,
      "var2" : 2,
      "var3" : {
        "className" : "subClass1",
        "var1" : 1,
        "var2" : 2
      }
    }
  },
  "implementorVar4" : 1000
}

public static void main(String[] args) {
    Implementor target = new Implementor(1, "hello",
            new SubClass2(1, 2,
                    new SubClass3(1F, 2,
                            new SubClass1(1, 2))),
            1000);
    try {
        ObjectMapper mapper = new ObjectMapper();
        String json = mapper
                .writerWithDefaultPrettyPrinter()
                .writeValueAsString(target);
        Implementor deserialised = mapper.readValue(json, Implementor.class);
        System.out.println(json);
        System.out.println(deserialised);
    } catch (Exception e) {
        e.printStackTrace();
    }
}


class Implementor {
    private int implementorVar1;
    private String implementorVar2;
    private A implementorVar3;
    private int implementorVar4;

    public Implementor() {}

    public Implementor(int implementorVar1, String implementorVar2, A implementorVar3, int implementorVar4) {
        this.implementorVar1 = implementorVar1;
        this.implementorVar2 = implementorVar2;
        this.implementorVar3 = implementorVar3;
        this.implementorVar4 = implementorVar4;
    }

    public int getImplementorVar1() {
        return implementorVar1;
    }

    public void setImplementorVar1(int implementorVar1) {
        this.implementorVar1 = implementorVar1;
    }
    // Other getters/setters omitted
    // Default configuration ABSOLUTELY requires getters and setters for all properties in all serialised classes
}

@JsonTypeInfo(use = JsonTypeInfo.Id.NAME, property = "className")
@JsonSubTypes({
        @JsonSubTypes.Type(value = SubClass1.class, name = "subClass1"),
        @JsonSubTypes.Type(value = SubClass2.class, name = "subClass2"),
        @JsonSubTypes.Type(value = SubClass3.class, name = "subClass3")
})
interface A {
    int func1();
    int func2();
}


class SubClass1 extends AbstractClass {
    private int var1;
    private int var2;

    public SubClass1() {}

    public SubClass1(int var1, int var2) {
        this.var1 = var1;
        this.var2 = var2;
    }

    @Override
    public int func1() {
        return 0;
    }

    @Override
    public int func2() {
        return 0;
    }

    // getters and setters omitted but they HAVE to be there
}

class SubClass2 extends AbstractClass {
    private int var1;
    private int var2;
    private A var3;

    public SubClass2() {}

    public SubClass2(int var1, int var2, A var3) {
        this.var1 = var1;
        this.var2 = var2;
        this.var3 = var3;
    }
    // getters and setters omitted but they HAVE to be there
}

class SubClass3 extends AbstractClass {
    private float var1;
    private int var2;
    private A var3;

    public SubClass3() {}

    public SubClass3(float var1, int var2, A var3) {
        this.var1 = var1;
        this.var2 = var2;
        this.var3 = var3;
    }

    @Override
    public int func1() {
        return 0;
    }

    @Override
    public int func2() {
        return 0;
    }
    // getters and setters omitted but they HAVE to be there
}