Jackson 2.0 JSON Traversal Example

ParseJson.java

package parse;

import com.fasterxml.jackson.core.JsonFactory;
import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.core.JsonToken;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;

import java.io.File;
import java.io.IOException;
import java.util.Iterator;

public class ParseJson {
    public static void main(String[] args) throws IOException {
        parseTree(new File("D:/tmp/tst.json"));
    }

    public static void parseTree(File file) throws IOException {
        ObjectMapper m = new ObjectMapper();

        JsonNode rootNode = m.readTree(file);

        printNode(rootNode, 0);
    }

    private static void printNode(JsonNode parentNode, int depth) {
        if (parentNode.isArray()) {
            printTabs(depth);
            System.out.println("[");

            Iterator<JsonNode> iter = parentNode.elements();

            while (iter.hasNext()) {
                JsonNode node = iter.next();

                if (node.isObject() || node.isArray()) {
                    printNode(node, depth+1);
                } else {
                    printTabs(depth);
                    System.out.print(node.asText());
                }
            }

            printTabs(depth);
            System.out.println("]");
        }
        if (parentNode.isObject()) {
            printTabs(depth);
            System.out.println("{");
            Iterator<String> iter = parentNode.fieldNames();

            while (iter.hasNext()) {
                String nodeName = iter.next();
                JsonNode node = parentNode.path(nodeName);

                printTabs(depth);
                System.out.println(nodeName + ": " + node.asText());

                if (node.isObject() || node.isArray()) {
                    printNode(node, depth+1);
                }
            }
            printTabs(depth);
            System.out.println("}");
        }
    }

    private static void printTabs(int count) {
        for (int i=0; i<count; i++) {
            System.out.print("\t");
        }
    }
}