使用Gson解析JSON数组到Java列表

从给定的

JSON

生成

SimpleTestClass

类型的

List

的最佳方法是什么，其中有一个新的

SimpleTestClass

对象，用于

JSON

的

recipients

数组中的值以及代码集

public class SimpleTestClass{
     String code;
     String recipient; 
}

JSON

有效负载：

{
     "code": 123,
     "recipients": [
        "888888",
        "222222"
     ]
}

类SimpleTestClass{
字符串代码；
列出收件人名单；
公共字符串getCode（）{
返回码；
}
公共无效设置码（字符串码）{
this.code=代码；
}
公共列表getRecipients（）{
返回收件人；
}
公共收件人（列出收件人）{
this.recipients=收件人；
}
}
公共类ServerMain{
公共静态void main（字符串[]args）{
Gson g=新的Gson（）；
SimpleTestClass类=g.fromJson（json，SimpleTestClass.class）；
}
}

如果

JSON

结构不适合

POJO

模型，您需要编写自定义反序列化程序或创建新的

POJO

模型，该模型适合

JSON

并在反序列化过程后将其转换为所需模型。下面您可以找到自定义反序列化器的解决方案，它允许您以非常灵活的方式处理给定的

JSON

：

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.JsonArray;
import com.google.gson.JsonDeserializationContext;
import com.google.gson.JsonDeserializer;
import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
import com.google.gson.JsonParseException;
import com.google.gson.annotations.JsonAdapter;
import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.List;

public class GsonApp {

    public static void main(String[] args) {
        String json = "{\"code\": 123,\"recipients\": [\"888888\",\"222222\"]}";

        Gson gson = new GsonBuilder().create();

        List<Recipient> recipients = gson.fromJson(json, Recipients.class).getRecipients();
        recipients.forEach(System.out::println);
    }
}

class RecipientsJsonDeserializer implements JsonDeserializer<Recipients> {

    @Override
    public Recipients deserialize(JsonElement json, Type typeOfT,
        JsonDeserializationContext context) throws JsonParseException {
        List<Recipient> recipients = new ArrayList<>();

        JsonObject root = json.getAsJsonObject();
        String code = root.get("code").getAsString();
        JsonArray recipientsArray = root.getAsJsonArray("recipients");
        recipientsArray.forEach(item -> {
            recipients.add(new Recipient(code, item.getAsString()));
        });

        return new Recipients(recipients);
    }
}

@JsonAdapter(RecipientsJsonDeserializer.class)
class Recipients {

    private final List<Recipient> recipients;

    public Recipients(List<Recipient> recipients) {
        this.recipients = recipients;
    }

    // getters, toString
}

class Recipient {

    private final String code;
    private final String recipient;

    public Recipient(String code, String recipient) {
        this.code = code;
        this.recipient = recipient;
    }

    // getters, toString
}

---

对但是，如果想要确切的结构：对于每个接收者，使用给定代码创建新的SimpleTestClass对象，该怎么办？您能详细解释一下吗？例如，在收件人数组中的json中，我们有两个值“88888”和“22222”。我想找到生成SimpleTestClass类型的两个对象的最佳方法，一个用于“88888”，另一个用于“22222”，其中设置了代码，在这种情况下是“123”。我只是在寻找做这件事的最佳方式，也许是用Gson做的

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.JsonArray;
import com.google.gson.JsonDeserializationContext;
import com.google.gson.JsonDeserializer;
import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
import com.google.gson.JsonParseException;
import com.google.gson.annotations.JsonAdapter;
import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.List;

public class GsonApp {

    public static void main(String[] args) {
        String json = "{\"code\": 123,\"recipients\": [\"888888\",\"222222\"]}";

        Gson gson = new GsonBuilder().create();

        List<Recipient> recipients = gson.fromJson(json, Recipients.class).getRecipients();
        recipients.forEach(System.out::println);
    }
}

class RecipientsJsonDeserializer implements JsonDeserializer<Recipients> {

    @Override
    public Recipients deserialize(JsonElement json, Type typeOfT,
        JsonDeserializationContext context) throws JsonParseException {
        List<Recipient> recipients = new ArrayList<>();

        JsonObject root = json.getAsJsonObject();
        String code = root.get("code").getAsString();
        JsonArray recipientsArray = root.getAsJsonArray("recipients");
        recipientsArray.forEach(item -> {
            recipients.add(new Recipient(code, item.getAsString()));
        });

        return new Recipients(recipients);
    }
}

@JsonAdapter(RecipientsJsonDeserializer.class)
class Recipients {

    private final List<Recipient> recipients;

    public Recipients(List<Recipient> recipients) {
        this.recipients = recipients;
    }

    // getters, toString
}

class Recipient {

    private final String code;
    private final String recipient;

    public Recipient(String code, String recipient) {
        this.code = code;
        this.recipient = recipient;
    }

    // getters, toString
}

Recipient{code='123', recipient='888888'}
Recipient{code='123', recipient='222222'}