Gsonの使い方

GsonShow.java

package gsonshow;

import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Paths;

import com.google.gson.Gson;

public class GsonShow {

	public static void main(String[] args) throws IOException {
		Order o1 = new Order("かき氷シロップ", 1, 300);
		Order o2 = new Order("かき氷シロップ", 2, 300);
		Order o3 = new Order("かき氷シロップ", 1, 310);
		Order o4 = new Order("かき氷シロップ いちご", 1, 300);
		
		Gson gson = new Gson();
		System.out.println(gson.toJson(o1));
		
		String s = "{\"product\":\"スイカ\",\"count\":1,\"price\":1000}";
		Order o5 = gson.fromJson(s, Order.class);
		System.out.println(o5);

		byte[] bytes = Files.readAllBytes(Paths.get("datafile.json"));
		String datafileStr = new String(bytes, StandardCharsets.UTF_8);
		Order[] o6 = gson.fromJson(datafileStr, Order[].class);
		System.out.println(o6);
	}
}

Order.java

package gsonshow;

public class Order {
	private String product;
	private int count;
	private int price;
	
	public Order(String product, int count, int price) {
		this.product = product;
		this.count = count;
		this.price = price;
	}

	public String getProduct() {
		return product;
	}

	public int getCount() {
		return count;
	}

	public int getPrice() {
		return price;
	}
	
	@Override
	public String toString() {
		return String.format("Order(%s,%d,%d)", product, count, price);
	}
}