用Jackson和Mockito序列化对象时的无限递归

Question

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import java.io.Serializable;
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.when;

public class Person implements Serializable {
    private String name;
    private int age;

    // Public getters and setters...

    public static void main(String[] args) {
        String name = "Bob";
        int age = 21;
        ObjectMapper objectMapper = new ObjectMapper();

        // attempt serialization with real object
        Person person = new Person();
        person.setName(name);
        person.setAge(age);
        try {
            System.out.println(objectMapper.writeValueAsString(person));
        } catch (JsonProcessingException e) {
            e.printStackTrace();
            System.err.println("Failed to serialize real object");
        }

        // attempt serialization with mock object
        Person mockPerson = mock(Person.class);
        when(mockPerson.getName()).thenReturn(name);
        when(mockPerson.getAge()).thenReturn(age);
        try {
            System.out.println(objectMapper.writeValueAsString(mockPerson));
        } catch (JsonProcessingException e) {
            e.printStackTrace();
            System.err.println("Failed to serialize mock object.");
        }
    }

所以，我的问题是：有没有办法迫使杰克逊使用getter方法？我在类上尝试了@JSONIgnoreProperties，在字段上尝试了@JSONIgore，在方法上尝试了@JSONProperty（不同的组合，都没有成功）。或者，我必须编写自己的自定义序列化程序吗？

谢了！

Answer 1

以下是一个适用于特定情况的解决方案：

首先，您需要创建一个PersonMixin，因为您无法向模拟添加所需的注释。

import com.fasterxml.jackson.annotation.JsonAutoDetect;
import com.fasterxml.jackson.annotation.JsonProperty;


@JsonAutoDetect(getterVisibility = JsonAutoDetect.Visibility.NONE, isGetterVisibility = JsonAutoDetect.Visibility.NONE)
public interface PersonMixin {

    @JsonProperty
    String getName();

    @JsonProperty
    Integer getAge();
}

现在，像下面的代码一样使用对象映射器，您将获得与序列化实际对象时相同的结果：

Person mockPerson = mock(Person.class);
when(mockPerson.getName()).thenReturn(name);
when(mockPerson.getAge()).thenReturn(age);
objectMapper.addMixInAnnotations(Person.class, PersonMixin.class);
try {
    System.out.println(objectMapper.writeValueAsString(mockPerson));
} catch (JsonProcessingException e) {
    e.printStackTrace();
    System.err.println("Failed to serialize mock object.");
}