Question

我正在尝试使用GSON 2.2.2（第一次）将JSON映射到Java POJO。我正在点击第三方RESTful Web服务，这是我回来的JSON的一个例子：

{
    "response": {
        "job":{
            "eta":-1,
            "status":"approved",
            "mt":1,
            "lc_tgt":"fr",
            "body_src":"Please translated me.",
            "body_tgt":"S'il vous plaît traduire moi.",
            "unit_count":3,
            "tier":"machine",
            "credits":0,
            "ctime":"2013-02-07 14:56:12.391963",
            "lc_src":"en",
            "slug":"0",
            "job_id":"NULL"
        }
    },
    "opstat":"ok"
}

POJO我试图将其映射到：

public class Job {
    // correlates to "eta"
    private int eta;

    // correlates to "body_src"
    private String sourceBody;

    // correlates to "ctime"
    private java.util.Date creationTimestamp;

    // Getters and setters for all 3 properties
}

当我运行以下代码时，我没有任何异常，但print语句只打印“null”：

// Hit the 3rd party service and get the JSON (example above).
JSONObject json = hitRestfulWebService();

Gson gson = new Gson();

// json.toString = "{response":{"job":{ ..."
Job job = gson.fromJson(json.toString(), Job.class);

System.out.println(job.getSourceBody());

我唯一的猜测是GSON无法弄清楚如何将3个JSON字段映射到我的3 Job属性。有人可以帮我弄清楚这个映射需要什么吗？提前谢谢。

Answer 1

您可以使用注释来定义哪个json字段映射到哪个对象成员，例如：

class SomeClass
{
   @SerializedName("body-src")
   String myString1;

   @SerializedName("header-src")
   String myString2;
...

Answer 2

使用不响应但响应.job

不

  {   "response": {..

使用

 { "eva": ..

这可能有所帮助;

    String a = "{\"response\": {\"job\":{\"eta\":-1,\"status\":\"approved\",\"mt\":1,\"lc_tgt\":\"fr\",\"body_src\":\"Please translated me.\",\"body_tgt\":\"S'il vous plaît traduire moi.\",\"unit_count\":3,\"tier\":\"machine\",\"credits\":0,\"ctime\":\"2013-02-07 14:56:12.391963\",\"lc_src\":\"en\",\"slug\":\"0\",\"job_id\":\"NULL\"}},\"opstat\":\"ok\"}";



    Job j = I.gson().fromJson(
            ((JsonObject) ((JsonObject) new JsonParser().parse(a)).get("response")).get("job"), Job.class);

    System.out.println(j.getEta());

Answer 3

public class Response{
  private Job job;

  //generate setter and getter
}

public class Job {
    // correlates to "eta"
    private int eta;

    // correlates to "body_src"
    private String sourceBody;

    // correlates to "ctime"
    private java.util.Date creationTimestamp;

    // Getters and setters for all 3 properties
}

现在在Gson

JSONObject json = hitRestfulWebService();

Gson gson = new Gson();

// json.toString = "{response":{"job":{ ..."
Job job = gson.fromJson(json.toString(), Response.class);

GSON映射POJO属性的空值

3 个答案: