@Dayou Zhou using json-simple import org.json.JSONObject; public class JSONParser { public static void main(String[] args) { String jsonStr = "{\"field1\":1,\"field2\":\"abc\"}"; JSONObject json = new JSONObject(jsonStr); Person person = new Person(); person.setKey(json.getInt("field1")); person.setValue(json.getString("field2")); System.out.println(person.toString()); } } class Person { int key; String value; @Override public String toString() { return "Person{" + "key=" + key + ", value=" + value + '}'; } public int getKey() { return key; } public void setKey(int key) { this.key = key; } public String getValue() { return value; } public void setValue(String value) { this.value = value; } } maven dependency <dependency> <groupId>org.json</groupId> <artifactId>json</artifactId> <version>20160810</version> </dependency> <dependency> <groupId>com.googlecode.json-simple</groupId> <artifactId>json-simple</artifactId> <version>1.1.1</version> <type>jar</type> </dependency> output Person{key=1, value=abc} ... View more

Please select the best answer, from your comments, it is not clear who'd helped you the most ... View more

nifi is decoupled from Hadoop, you can get by with just a few nodes (3) to get decent throughput but flexibility and ease of use will pay for itself in the long run. We typically recommend to separate HDP and HDF. ... View more

@Amber Kulkarni please open this as a new thread. ... View more