EN
Java - convert object to JSON String with Jackson lib
4 points
In this short article, we would like to show how to convert any Java object to JSON, using an external Jackson library.
Quick solution:
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// import com.fasterxml.jackson.core.JsonProcessingException;2
// import com.fasterxml.jackson.databind.ObjectMapper;3
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ObjectMapper objectMapper = new ObjectMapper();5
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User userObject = new User("John", 21);7
String userJson = objectMapper.writeValueAsString(userObject);8
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System.out.println(userJson); // {"name":"John","age":21}
Hint: to know how to attach Jackson
*.jarlibrary to your project read this article.
Note: if you want to parse JSON to
Objectread this article.
Maven repository: https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-databind
Full example of how to use Jackson library.
Main.java file content:
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package examples;2
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import com.fasterxml.jackson.core.JsonProcessingException;4
import com.fasterxml.jackson.databind.ObjectMapper;5
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public class Main {7
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public static void main(String[] arg) throws JsonProcessingException {9
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ObjectMapper objectMapper = new ObjectMapper();11
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User userObject = new User("John", 21);13
String userJson = objectMapper.writeValueAsString(userObject);14
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System.out.println(userJson); // {"name":"John","age":21}16
}17
}Example output:
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{"name":"John","age":21}
User.java file content:
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package examples;2
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public class User {4
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private String name;6
private int age;7
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// it is good to add no-arguments constructor too9
public User() {10
// nothing here ...11
}12
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public User(String name, int age) {14
this.name = name;15
this.age = age;16
}17
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public String getName() {19
return this.name;20
}21
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public int getAge() {23
return this.age;24
}25
}