一文带你了解gson如何序列化子类

@Data
@ToString
public class Person {
    //姓名
    private String name;
    //年龄
    private Integer age;
    //类型，0代表Student，1代表worker
    private Integer type;
}

@Data
@ToString
public class Student extends Person{
    //学校
    private String school;
}

@Data
@ToString
public class Worker extends Person{
    //薪水
    private Integer salary;
}

{
    "group":[
        {
            "school":"Hello中学",
            "name":"张三",
            "age":16,
            "type":0
        },
        {
            "salary":100000,
            "name":"李四",
            "age":35,
            "type":1
        }
    ]
}

public class MyTest {
    public static void main(String[] args) {
        Gson gson = new Gson();
        String jsonStr = "{\"group\":[{\"school\":\"Hello中学\",\"name\":\"张三\",\"age\":16,\"type\":0},{\"salary\":100000,\"name\":\"李四\",\"age\":35,\"type\":1}]}";
        Type type = new TypeToken<PersonGroup>() {
        }.getType();

        PersonGroup personGroup = gson.fromJson(jsonStr, type);
        //为了打断点
        System.out.println();
    }
}

public class PersonDesrializer implements JsonDeserializer<Person> {
    private Gson gson = new Gson();

    private Map<Integer, Class<? extends Person>> typeMap = new HashMap<>();

    public PersonDesrializer() {
        typeMap.put(0,Student.class);
        typeMap.put(1,Worker.class);
    }

    @Override
    public Person deserialize(JsonElement jsonElement, Type type, JsonDeserializationContext jsonDeserializationContext) throws JsonParseException {
        JsonObject jsonObject = jsonElement.getAsJsonObject();
        Class<? extends Person> typeClazz = this.typeMap.get(jsonObject.get("type").getAsInt());
        return gson.fromJson(jsonElement,typeClazz);
    }
}

public class MyTest {
    public static void main(String[] args) {
        Gson gson = new GsonBuilder()
                .serializeNulls()
                .registerTypeAdapter(Person.class, new PersonDesrializer())
                .create();
        String jsonStr = "{\"group\":[{\"school\":\"Hello中学\",\"name\":\"张三\",\"age\":16,\"type\":0},{\"salary\":100000,\"name\":\"李四\",\"age\":35,\"type\":1}]}";
        Type type = new TypeToken<PersonGroup>() {
        }.getType();

        PersonGroup personGroup = gson.fromJson(jsonStr, type);
        //为了打断点
        System.out.println();
    }
}