java - 使用 jackson : get duplicated fields in json string

Question

我有一个 Jackson 的 POJO注释:

public class Person {
    @JsonProperty("first_name")
    private String firstName;

    @JsonProperty("last_name")
    private String lastName;

    public String getFirstName() {
        return this.firstName;
    }

    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }

    public String getLastName() {
        return this.lastName;
    }

    public void setLastName(String lastName) {
        this.lastName = lastName;
    }

}

然后我创建了一个 Person 实例并将其解析为 json 字符串:

Person p = new Person();
p.setFirstName("John");
p.setLastName("Smith");

//parse to json string
ObjectMapper mapper = new ObjectMapper();
String personJson = mapper.writeValueAsString(p);

但是我得到的json字符串(personJson)是这样的:

{"first_name":"John","last_name":"Smith","firstName":"John","lastName":"Smith"}

为什么我得到重复的字段“first_name”和“firstName”，所以“last_name”和“lastName”在JSON字符串中？

=====更新===

我也试过:

注释:

@JsonAutoDetect(fieldVisibility = JsonAutoDetect.Visibility.ANY, getterVisibility = JsonAutoDetect.Visibility.NONE,
        setterVisibility = JsonAutoDetect.Visibility.NONE, creatorVisibility = JsonAutoDetect.Visibility.NONE,
        isGetterVisibility = JsonAutoDetect.Visibility.NONE)

对象映射器:

ObjectMapper mapper = new ObjectMapper();
    mapper.getSerializationConfig().getDefaultVisibilityChecker()
            .withFieldVisibility(JsonAutoDetect.Visibility.ANY)
            .withGetterVisibility(JsonAutoDetect.Visibility.NONE)
            .withSetterVisibility(JsonAutoDetect.Visibility.NONE)
            .withCreatorVisibility(JsonAutoDetect.Visibility.NONE);

但我仍然在其他一些 POJO 中得到 JSON 中的重复属性...

Answer 1

我设法自己解决了这个问题。

在 UPDATE 之后我仍然在 JSON 中得到重复字段的原因是我的其他 POJO 中有 boolean 属性，它产生以 "is"开头的访问器方法，例如:

public class Other {
   @JsonProperty("money_paid")
   private boolean moneyPaid;

   public boolean isMoneyPaid() {
    return moneyPaid;
   } 
   ... 
}

因此，生成的 json 包含 {money_paid:true, moneyPaid:true}。为了摆脱它，我只是在 setVisibilityChecker 时对 mapper 添加了一个限制，即:

.withIsGetterVisibility(JsonAutoDetect.Visibility.NONE)