Friday, 18 October 2013

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

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