从REST解析JSON对象和数组

Question

I have the following JSON that I would like to parse into JAVA from REST. I have an AR object and a method and takes wine an argument. How would I do it?

 {
    "type": "AR",
    "selection_month": "Feb/2015",
    "wines": [
      {
          "variety": "RED",
          "wine_type": "TABLE",
          "label_name": "The Mission",
          "grape": "Merlot",
          "region": "Napa",
          "country": "USA",
          "maker": "Sterling",
          "year": "2014"
      },
      {
          "variety": "RED",
          "wine_type": "TABLE",
          "label_name": "Joseph Phelps Cabernet Sauvignon 2012",
          "grape": "Cabernet Sauvignon",
          "region": "Napa",
          "country": "USA",
          "maker": "Joseph Phelps",
          "year": "2012"
      },
      {
          "variety": "RED",
          "wine_type": "TABLE",
          "label_name": "Round Pond Estate Rutherford",
          "grape": "Cabernet Sauvignon",
          "region": "Napa",
          "country": "USA",
          "maker": "Rutherford",
          "year": "2014"
      },
      {
          "variety": "RED",
          "wine_type": "TABLE",
          "label_name": "Dona Paula Black Label",
          "grape": "Bordeaux",
          "region": "",
          "country": "Argentina",
          "maker": "Dona Paula",
          "year": "2013"
      },
      {
          "variety": "RED",
          "wine_type": "TABLE",
          "label_name": "Schug Sonoma Coast Pinot Noir",
          "grape": "Pinot Noir",
          "region": "Sonoma Valley",
          "country": "USA",
          "maker": "Walter Schug",
          "year": "2013"
      },
      {
          "variety": "RED",
          "wine_type": "TABLE",
          "label_name": "Caymus Special Selection Cabernet Sauvignon",
          "grape": "Cabernet Sauvignon",
          "region": "Napa Valley",
          "country": "USA",
          "maker": "Charles F. Wagner",
          "year": "2014"
      }
    ]
  }

I have the following method going

@POST
public Response addAR(InputStream incomingData){
    String parsedJson = jsonStreamToString(incomingData);
    try {
        JSONObject json = new JSONObject(parsedJson);

        String name = json.getString("name");


        int uid = useCase.createAR(name);

        JSONObject jsonResponse = new JSONObject(new JSONStringer().object()
                .key("id").value(uid).endObject().toString());

        return Response.status(201).entity(jsonResponse.toString()).build();
    } catch (JSONException e) {

        e.printStackTrace();
        return Response.status(404).entity(e.toString()).build();
    }
}

Answer 1

I'd suggest not trying to parse everything yourself, and use POJOs. Let Jackson parse the JSON into your POJO. Wine could be a class and AR whatever that is can be a class with a List<Wine>

"I am using Jersey JAX_RS 2.0"

To get Jackson support, if you are using Maven, simply add this dependency

<dependency>
    <groupId>org.glassfish.jersey.media</groupId>
    <artifactId>jersey-media-json-jackson</artifactId>
    <version>${jersey2.version}</version>
</dependency>

If you're not using Maven, then download these jars

• jersey-media-json-jackson - Select the version (matching your Jersey 2.x version, then download)

• Get all the ones from the below image

  

  I had an image from another post with v2.2.3- disregard the version. The version you want to get 2.3.2 for all of them. They can all be found at the above link, for the first dependency. Just search for them in the search bar. When you find it, select the version and download it.

Once you have all the jars/dependency you can simply use POJOs converted from your JSON. For example you can have a Wine class

public class Wine {
    private String variety;
    @JsonProperty("wine_type")
    private String wineType;
    @JsonProperty("label_name")
    private String labelName;
    private String grape;
    private String country;
    private String maker;
    private String year;

    // proper Getters and Setters mathing for form
    // public String getVariety()
    // public void setVariety(String variety)
    // basically following JavaBean naming convention
}

You will need proper JavaBean style getters and setters. You'll notice a couple of the fields have @JsonProperty annotation. That is because JSON properties with _ (underscore) don't map well to the methods, so we need to name the property.

Then you can have another class that has a List<Wine> , along with the other properties of the top level JSON object. for example

public class AR {
    private String type;
    @JsonProperty("selection_month")
    private String selectionMonth;
    private List<Wine> wines;

    // Getters and Setters
}

Now you can simply have an AR type as the method parameter. An you can work with the AR object directly

@POST
@Consumes(MediaType.APPLICATION_JSON)
public Response addAR(AR ar){