Jackson Streaming API to Write JSON

Hi guys,
In this post i show you how to create JSON file using Jackson Streaming API.

Jackson supports read and write JSON via high-performance Jackson Streaming APIs, or incremental mode. Read this Jackson Streaming APIs document for detail explanation on the benefit of using streaming API.

Jackson’s streaming processing is high-performance, fast and convenient, but it’s also difficult to use, because you need to handle each and every detail of JSON data.

In this tutorial, i show you how to use following Jackson streaming APIs to read and write JSON data.

1. JsonGenerator – Write to JSON.
2. JsonParser – Parse JSON.

JsonGenerator

In this example, you use “JsonGenerator” to write JSON “field name”, “values” and “array of values” into a file name “file.json“. See code comments for self-explanatory.

import java.io.File;
import java.io.IOException;
import com.fasterxml.jackson.core.JsonEncoding;
import com.fasterxml.jackson.core.JsonFactory;
import com.fasterxml.jackson.core.JsonGenerationException;
import com.fasterxml.jackson.core.JsonGenerator;

public class WriteJson {
public static void main(String[] args) {

try {

JsonFactory jfactory = new JsonFactory();

/*** Write JSON TO FILE ***/
JsonGenerator jGenerator = jfactory.createGenerator(new File("./src/data.json"), JsonEncoding.UTF8);
jGenerator.writeStartObject();  //{

jGenerator.writeStringField("blogname", "oraclejavatechzone.com");
jGenerator.writeStringField("subject", "java");

jGenerator.writeNumberField("year", 2013);

jGenerator.writeFieldName("posts"); //"posts":

jGenerator.writeStartArray(); //[
jGenerator.writeString("post 1");
jGenerator.writeString("post 2");
jGenerator.writeString("post 3");

jGenerator.writeEndArray(); \\]
jGenerator.writeEndObject(); //}

jGenerator.close();
System.out.println("File write successfully");

} catch (JsonGenerationException e) {
e.printStackTrace();

} catch (IOException e) {
e.printStackTrace();

}

}
}

As result, following new file named “data.json” is created :

That's All Folks...