How to get a json response using jackson?

Question

I am new to jackson, and I had a sample json output need to use jackson to get this data as response, I had created the pojo classes for that, as I know this kind of problem to be achieved by json simple, but I am not getting any idea to do this usong jackson. Please can some one provide some help.

This is my sample json Data -

{
"apmmetrics": [
    {
        "metric": "Somevalue",
        "level": "somevalue",
        "data": [
            {
                "host": "someValue",
                "instance": "someValue",
                "app": "someValue",
                "series": [
                    {
                        "bucket": "201607210949",
                        "max": 300,
                        "min": 15,
                        "avg": 57.55,
                        "total": 1899,
                        "count": 33
                    },
                    {
                        "bucket": "201607210948",
                        "max": 437,
                        "min": 13,
                        "avg": 93.5,
                        "total": 13464,
                        "count": 144
                    },
                    {
                        "bucket": "201607210947",
                        "max": 431,
                        "min": 13,
                        "avg": 86.25,
                        "total": 28376,
                        "count": 329
                    }
                ]
            }
        ]
    }
]}

These are my pojo classes--

public class MetricsCollection {

private String metric;
private String level;
private List<MetricsGroup> data;
private transient Map<String, MetricsGroup> meta;

}

public class MetricsGroup {

private String host;
private String instance;
private String app;
private List<GenericMetrics> series;
private transient Map<String, GenericMetrics> metaMap;
}


public class BaseMetrics implements Serializable {
private static final long serialVersionUID = -3249688349785265214L;
protected double max = 0.0;
protected double min = 0.0;
protected double avg = 0.0;
protected double total = 0.0;
protected long count = 0;
}


public class GenericMetrics extends BaseMetrics {

private static final long serialVersionUID = -9057601499394607167L;
private String bucket;
private transient long rc = 0;

}

please let me know how can I achieve this. It will be really thankful. Thanks in advance.

Answer 1

You should create another class (rootPojo) with an attribute array called apmmetrics of MetricsCollection . Then generate the json: mapper.writeValueAsString(rootPojo);

EDIT:

Or just:

final ObjectMapper mapper = new ObjectMapper();
final Map<String, List<MetricsCollection>> dataMap = ...
dataMap.put("apmmetrics", listOfMetricsCollection);
System.out.println(mapper.writeValueAsString(dataMap));