lining lining - 6 months ago 127
JSON Question

Convert JSON String to Pretty Print JSON output using Jackson

This is the JSON string I have-

{"attributes":[{"nm":"ACCOUNT","lv":[{"v":{"Id":null,"State":null},"vt":"java.util.Map","cn":1}],"vt":"java.util.Map","status":"SUCCESS","lmd":13585},{"nm":"PROFILE","lv":[{"v":{"Party":null,"Ads":null},"vt":"java.util.Map","cn":2}],"vt":"java.util.Map","status":"SUCCESS","lmd":41962}]}


I need to convert the above JSON string into Pretty Print JSON Output(using Jackson) like below-

{
"attributes": [
{
"nm": "ACCOUNT",
"lv": [
{
"v": {
"Id": null,
"State": null
},
"vt": "java.util.Map",
"cn": 1
}
],
"vt": "java.util.Map",
"status": "SUCCESS",
"lmd": 13585
},
{
"nm": "PROFILE
"lv": [
{
"v": {
"Party": null,
"Ads": null
},
"vt": "java.util.Map",
"cn": 2
}
],
"vt": "java.util.Map",
"status": "SUCCESS",
"lmd": 41962
}
]
}


Can anyone provide me an example basis on my example above? How to achieve this scenario, I know there are lot of example but I am not able to understand those properly. Any help will be appreciated with a simple example.

Updated:

Below is the code I am using

ObjectMapper mapper = new ObjectMapper();
System.out.println(mapper.defaultPrettyPrintingWriter().writeValueAsString(jsonString));


But this doesn't works with the way I needed the output as mentioned above

Here's is the POJO I am using for the above JSON-

public class UrlInfo implements Serializable {

private List<Attributes> attribute;

}

class Attributes {

private String nm;
private List<ValueList> lv;
private String vt;
private String status;
private String lmd;

}


class ValueList {
private String vt;
private String cn;
private List<String> v;
}


Can anyone tell me whether I got the right POJO for the JSON or not?

Updated:-

String result = restTemplate.getForObject(url.toString(), String.class);

ObjectMapper mapper = new ObjectMapper();
Object json = mapper.readValue(result, Object.class);

String indented = mapper.defaultPrettyPrintingWriter().writeValueAsString(json);

System.out.println(indented);//This print statement show correct way I need

model.addAttribute("response", (indented));


Below line prints out something like this-

System.out.println(indented);


{
"attributes" : [ {
"nm" : "ACCOUNT",
"error" : "null SYS00019CancellationException in CoreImpl fetchAttributes\n java.util.concurrent.CancellationException\n\tat java.util.concurrent.FutureTask$Sync.innerGet(FutureTask.java:231)\n\tat java.util.concurrent.FutureTask.",
"status" : "ERROR"
} ]
}


which is the way I needed to be shown. But when I add it to model like this-

model.addAttribute("response", (indented));


And then shows it out in a resultform jsp page like below-

<fieldset>
<legend>Response:</legend>
<strong>${response}</strong><br />

</fieldset>


I get something like this-

{ "attributes" : [ { "nm" : "ACCOUNT", "error" : "null
SYS00019CancellationException in CoreImpl fetchAttributes\n
java.util.concurrent.CancellationException\n\tat
java.util.concurrent.FutureTask$Sync.innerGet(FutureTask.java:231)\n\tat
java.util.concurrent.FutureTask.", "status" : "ERROR" } ] }


which I don't need. I needed the way it got printed out above. Can anyone tell me why it got happened like this?

Answer

To indent any old JSON, just bind it as Object, like:

Object json = mapper.readValue(input, Object.class);

and then write it out with indentation:

String indented = mapper.writerWithDefaultPrettyPrinter().writeValueAsString(json);

this avoids your having to define actual POJO to map data to.

Or you can use JsonNode (JSON Tree) as well.

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