如何在Java中操作HTTP json响应数据

Question

HttpGet getRequest=new HttpGet("/rest/auth/1/session/");
getRequest.setHeaders(headers);
httpResponse = httpclient.execute(target,getRequest);

entity = httpResponse.getEntity();

System.out.println(EntityUtils.toString(entity));

Output as follows in json format

----------------------------------------
{"session":{"name":"JSESSIONID","value":"5F736EF0A08ACFD7020E482B89910589"},"loginInfo":{"loginCount":50,"previousLoginTime":"2014-11-29T14:54:10.424+0530"}}
----------------------------------------

What I want to know is how to you can manipulate this data using Java without writing it to a file? I want to print name, value in my code

Jackson library is preferred but any would do.

thanks in advance

Answer 1

Here's two ways to do it without a library.

NEW (better) Answer:

findInLine might work even better. ( scannerName.findInLine(pattern); )

Maybe something like:

s.findInLine("{"session":{"name":"(\\w+)","value":"(\\w+)"},"loginInfo":{"loginCount":(\\d+),"previousLoginTime":"(\\w+)"}}");

w matches word characters (letters, digits, and underscore), d matches digits, and the + makes it match more than once (so it doesnt stop after just one character).

Read about patterns here https://docs.oracle.com/javase/7/docs/api/java/util/regex/Pattern.html

OLD Answer:

I'm pretty sure you could use a scanner with a custom delimiter here.

Scanner s = new Scanner(input).useDelimiter("\"");

Should return something like:

{
session
:{
name
:
JSESSIONID
,
value
:
5F736EF0A08ACFD7020E482B89910589

And so on. Then just sort through that list/use a smarter delimiter/remove the unnecessary bits. Getting rid of every other item is a pretty decent start.

https://docs.oracle.com/javase/7/docs/api/java/util/Scanner.html has info on this.

Answer 2

You may use this JSON library to parse your json string into JSONObject and read value from that object as show below :

JSONObject json = new JSONObject(EntityUtils.toString(entity));
JSONObject sessionObj =  json.getJSONObject("session");
System.out.println(sessionObj.getString("name"));

You need to read upto that object from where you want to read value. Here you want the value of name parameter which is inside that session object, so you first get the value of session as JSONObject using getJSONObject(KeyString) and read name value from that object using function getString(KeyString) as show above.

May this will help you.

Answer 3

I higly recomend http-request built on apache http api.

private static final HttpRequest<Map<String, Map<String, String>>> HTTP_REQUEST = HttpRequestBuilder.createGet(yourUri, new TypeReference<Map<String, Map<String, String>>>{})
    .addDefaultHeaders(headers)
    .build();

public void send(){
   ResponseHandler<Map<String, Map<String, String>>> responseHandler = HTTP_REQUEST.execute();
   Map<String, Map<String, String>> data = responseHandler.get();
}

If you want use jackson you can:

entity = httpResponse.getEntity();
ObjectMapper mapper = new ObjectMapper();
Map<String, Map<String, String>> data = mapper.readValue(entity.getContent(),  new TypeReference<Map<String, Map<String, String>>>{});