如何为Json对象使用动态属性名称 [英] How to use dynamic property names for a Json object

问题描述

如何使JSON属性名称动态化.例如

How can we make the JSON property name dynamic. For example

public class Value {
    @JsonProperty(value = "value")
    private String val;

    public void setVal(String val) {
        this.val = val;
    }

    public String getVal() {
        return val;
    }
}

序列化此对象时，它另存为{"value": "actual_value_saved"}，但我想使键像{"new_key": "actual_value_saved"}一样动态.非常感谢您的帮助.

when serializing this object it's saved as {"value": "actual_value_saved"} but I want to make the key also dynamic like {"new_key": "actual_value_saved"}. Any help is much appreciated.

推荐答案

您可以使用

You can use JsonAnySetter JsonAnyGetter annotations. Behind you can use Map instance. In case you have always one-key-object you can use Collections.singletonMap in other case use HashMap or other implementation. Below example shows how easy you can use this approach and create as many random key-s as you want:

import com.fasterxml.jackson.annotation.JsonAnyGetter;
import com.fasterxml.jackson.annotation.JsonAnySetter;
import com.fasterxml.jackson.databind.ObjectMapper;
import java.util.Collections;
import java.util.Map;
import java.util.Objects;

public class JsonApp {

    public static void main(String[] args) throws Exception {
        DynamicJsonsFactory factory = new DynamicJsonsFactory();
        ObjectMapper mapper = new ObjectMapper();

        System.out.println(mapper.writeValueAsString(factory.createUser("Vika")));
        System.out.println(mapper.writeValueAsString(factory.createPhone("123-456-78-9")));
        System.out.println(mapper.writeValueAsString(factory.any("val", "VAL!")));
    }
}

class Value {

    private Map<String, String> values;

    @JsonAnySetter
    public void put(String key, String value) {
        values = Collections.singletonMap(key, value);
    }

    @JsonAnyGetter
    public Map<String, String> getValues() {
        return values;
    }

    @Override
    public String toString() {
        return values.toString();
    }
}

class DynamicJsonsFactory {

    public Value createUser(String name) {
        return any("name", name);
    }

    public Value createPhone(String number) {
        return any("phone", number);
    }

    public Value any(String key, String value) {
        Value v = new Value();
        v.put(Objects.requireNonNull(key), Objects.requireNonNull(value));

        return v;
    }
}

上面的代码显示:

{"name":"Vika"}
{"phone":"123-456-78-9"}
{"val":"VAL!"}

这篇关于如何为Json对象使用动态属性名称的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！