Java Tutorials Corner: JSON Streaming API to Read JSON

JSON Streaming API to Read JSON

In this tutorial we are going to see how to read JSON from file using JsonParser class available in Jackson.Jackson Streaming API is high-performance Java API for read write JSON.
JsonGenerator – is used to write JSON as String and File.
1. Create project called JSONExample.
2. Create package called com.javatutorialscorner.jackson
3. add jackson-mapper-asl-1.9.13.jar, jackson-core-asl-1.9.13.jar into build path.
4. Create java class called JSONParserExample under com.javatutorialscorner.jackson
JSONParserExample.java

package com.javatutorialscorner.jackson;

import java.io.File;
import java.io.IOException;

import org.codehaus.jackson.JsonFactory;
import org.codehaus.jackson.JsonParseException;
import org.codehaus.jackson.JsonParser;
import org.codehaus.jackson.JsonToken;

public class JSONParserExample {

 /**
  * @param args
  */
 public static void main(String[] args) {
  // TODO Auto-generated method stub
  JsonFactory factory = null;
  JsonParser jsonParser = null;

  try {
   factory = new JsonFactory();
   jsonParser = factory.createJsonParser(new File(
     "C:\\jtc\\javatutorialscorner.json"));
   while (jsonParser.nextToken() != JsonToken.END_OBJECT) {

    String field = jsonParser.getCurrentName();
    if ("name".equals(field)) {
     jsonParser.nextToken();
     System.out.println("Name : " + jsonParser.getText());
    } else if ("rank".equals(field)) {
     jsonParser.nextToken();
     System.out.println("Rank : " + jsonParser.getIntValue());
    } else if ("Tutorials".equals(field)) {
     jsonParser.nextToken();
     while (jsonParser.nextToken() != JsonToken.END_ARRAY) {
      System.out.println("Tutorials : "
        + jsonParser.getText());
     }
    }
   }
   jsonParser.close();
  } catch (JsonParseException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  } catch (IOException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }

 }

}

Now run the program see the following output in console.

Name : Java Tutorials Corner

Rank : 1

Tutorials : Java

Tutorials : Servlet

Tutorials : JSP

Tutorials : Struts 1.x

Tutorials : Struts 2.x

Tutorials : Spring

Tutorials : Hibernate

Tutorials : Log4j

Tutorials : JSON

Tutorials : Web Services

Tutorials : JSF

Tutorials : Eclipse