禁用每个ObjectMapper的字段序列化

Question

public class MyClass {

  @JsonProperty(access = WRITE_ONLY)
  private String field;

  ...

}

我想知道，是否有某种方法来指示对象映射器（或注入一些东西到它）以不同的方式处理这样的字段？

Answer 1

当您在客户端和服务器端使用通用模型类时，您可以使用com.fasterxml.jackson.databind.module类及其实现注册所有差异。如果某些jackson配置只能在一侧可用，您可以将其移动到MixIn类/接口，并仅在给定的一侧注册。

简单示例：

import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.json.JsonMapper;
import com.fasterxml.jackson.databind.module.SimpleModule;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

import java.io.IOException;

public class ClientServerApp {

    public static void main(String[] args) throws IOException {
        // Client side
        ObjectMapper clientMapper = JsonMapper.builder().build();

        // create payload on client side
        MyClass instance = new MyClass(1, "fieldValue");
        String payload = clientMapper.writeValueAsString(instance);

        // send to server
        System.out.println("Send: " + payload);
        // ..

        // Server side
        ObjectMapper serverMapper = JsonMapper.builder()
                .addModule(new ServerModule())
                .build();
        MyClass deserialized = serverMapper.readValue(payload, MyClass.class);
        System.out.println("Deserialized: " + deserialized);

        System.out.println("Payload on server side: " + serverMapper.writeValueAsString(deserialized));
    }
}

class ServerModule extends SimpleModule {
    public ServerModule() {
        setMixInAnnotation(MyClass.class, MyClassServerMixIn.class);
        // add other configuration
    }
}

@Data
@AllArgsConstructor
@NoArgsConstructor
class MyClass {

    private int id;
    private String field;
}

interface MyClassServerMixIn {

    @JsonProperty(access = JsonProperty.Access.WRITE_ONLY)
    String getField();
}

上面的代码打印：

Send: {"id":1,"field":"fieldValue"}
Deserialized: MyClass(id=1, field=fieldValue)
Payload on server side: {"id":1}