Convert Java object to JSON
This tutorial shows 2 ways for converting Java objects to JSON.
This kind of conversion is normally done via third-party libraries as it’s not supported by the JDK itself and requires a hard work to do it manually.
1- Gson
The most popular library used for converting Java objects to JSON is the Google Gson library.
Using Gson, you can get a JSON String out of an object through one line as the following:
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public static String convertUsingGson(Student student) { Gson gson = new Gson(); String studentJson = gson.toJson(student); return studentJson; } |
All you have to do is to include gson jar in the classpath.
P.S: It’s worth to mention that toJson() method accepts also Hashmap, ArrayList and Arrays.
2- Jackson
Another popular library is Jackson.
In order to convert Java objects to JSON using Jackson, you have to include 3 libraries: jackson-annotations, jackson-core and jackson-databind.
Here is the way:
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public static String convertUsingJackson(Student student) { String studentJson = ""; try { ObjectMapper mapper = new ObjectMapper(); studentJson = mapper.writeValueAsString(student); } catch(Exception ex) { System.out.println("Error while converting Student object to Json"); ex.printStackTrace(); } return studentJson; } |
P.S: writeValueAsString() method accepts also Hashmap, ArrayList and Arrays.
