Question

在填充以下类型的Json时获取空的Java对象。

a.json:
------
{
    "queries": [{
            "query": {
                "id": "q1",
                "description": "Fire query to get the Auth token !!"
            }
        }
    ],
    "executeQuery": ["q2", "q3"]
}

Query.java :
-----------
Note : @Data will take care of creating setter getter by Lombok library.

@Data
public class Query {
    @Expose @SerializedName("id") 
    String id;

    @Expose @SerializedName("description") 
    String description;
}

GRT.java :
---------- 
@Data
public class GRT{

    @Expose @SerializedName("queries") 
    List<Query> queries ;

    @Expose @SerializedName("executeQuery") 
    List<String> executeQuery;
}

Client call :
----------------------------------------------
private void readJson() throws IOException{
        String fileName = "a.json";

        // Get Gson object
        Gson gson = newGsonBuilder().excludeFieldsWithoutExposeAnnotation().create();  

        // read JSON file data as String
        String fileData = new String(Files.readAllBytes(Paths.get(fileName)));

        // parse json string to object
        GenericRestTestDefinition grtDef = gson.fromJson(fileData, GenericRestTestDefinition.class);

        System.out.println(grtDef.toString());

    }

打印以下内容：

GRT（查询= [查询（id =空，描述=空）]，executeQuery = [q2，q3]）

不知道为什么不填充GRT->查询对象吗？???

Answer 1

正确的JSON如下所示。

{
  "queries":
     [
       {"id":"q1","description":"Fire query to get the Auth token"},
       {"id":"q2","description":"Fire query to get the Auth token 2"}
     ]
}


public class Test {

    public static void main(String[] args) throws Exception {
        readJson();
    }

    private static void readJson() throws IOException {
        String json ="{\"queries\":[{\"id\":\"q1\",\"description\":\"Fire query to get the Auth token\"}]}";

        // Get Gson object
        Gson gson =  new GsonBuilder().excludeFieldsWithoutExposeAnnotation().create();

        GRT grt = new GRT();
        grt.setQueries(Arrays.asList( new Query[]{new Query("q1", "Fire query to get the Auth token")} ));
        System.out.println(gson.toJson(grt));

        // parse json string to object
        GRT grtDef = gson.fromJson(json, new TypeToken<GRT>(){}.getType());

        System.out.println(grtDef.queries.get(0));

    }

}

Answer 2

如果您无法更改json文件格式，则可以使用以下模式：

@Data
public class GRT{

    @Expose @SerializedName("queries")
    private List<QueryWrapper> queries = new ArrayList<>();

    public List<Query> getQueries() {
        return queries.stream().map(it->it.query).collect(Collectors.toList());
    }

    @Expose @SerializedName("executeQuery")
    List<String> executeQuery = new ArrayList<>();
}
@Data
public class QueryWrapper {
    @Expose @SerializedName("query")
    Query query;
}
@Data
public class Query {
    public
    @Expose @SerializedName("id")
    String id;

    @Expose @SerializedName("description")
    String description;
}

Gson不在Java List <object>中填充

打印以下内容：

2 个答案: