POJO<->JSONの相互変換にGroovyを使った場合のサンプル

GroovyPojoJsonSample.java

import groovy.lang.Binding;
import groovy.lang.GroovyShell;
import groovy.lang.Script;

import java.io.File;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;

/**
 * POJO <-> JSON Sample Using Groovy
 */
public class GroovyPojoJsonSample {
	/**
	 * Name class
	 */
	public static class Name {
		private String firstName;
		private String lastName;
		public Name() {
		}
		public Name(String firstName, String lastName) {
			this.firstName = firstName;
			this.lastName = lastName;
		}
		public String getFirstName() {
			return firstName;
		}
		public void setFirstName(String firstName) {
			this.firstName = firstName;
		}
		public String getLastName() {
			return lastName;
		}
		public void setLastName(String lastName) {
			this.lastName = lastName;
		}
		public String toString() {
			return lastName + " " + firstName;
		}
	}
	/**
	 * Profile class
	 */
	public static class Profile {
		private Name name;
		private int age;
		public Profile() {
			super();
		}
		public Profile(Name name, int age) {
			this();
			this.name = name;
			this.age = age;
		}
		public Name getName() {
			return name;
		}
		public void setName(Name name) {
			this.name = name;
		}
		public int getAge() {
			return age;
		}
		public void setAge(int age) {
			this.age = age;
		}
		public String toString() {
			return "name: " + name.toString() + ", age: " + age;
		}
	}
	/**
	 * SampleData class
	 */
	public static class SampleData {
		private List<Profile> profiles;
		public SampleData() {
			profiles = new ArrayList<>();
		}
		public SampleData(List<Profile> profiles) {
			this.profiles = profiles;
		}
		public List<Profile> getProfiles() {
			return profiles;
		}
		public void setProfiles(List<Profile> profiles) {
			this.profiles = profiles;
		}
		public String toString() {
			StringBuilder builder = new StringBuilder();
			for (Profile profile : profiles) {
				builder.append(builder.length() > 0 ? "," : "profiles:");
				builder.append(" [").append(profile).append("]");
			}
			return builder.toString();
		}
	}
	/**
	 * Category Class for Groovy asType()
	 */
	public static class SampleDataCategory {
		@SuppressWarnings({ "rawtypes", "unchecked" })
		public static Object asType(Map self, Class clazz) {
			if (clazz == SampleData.class) {
				SampleData result = new SampleData();
				List<Map> profiles = (List<Map>)self.get("profiles");
				for (Map profile : profiles) {
					result.getProfiles().add((Profile)asType(profile, Profile.class));
				}
				return result;
			}
			if (clazz == Profile.class) {
				Map name = (Map)self.get("name");
				return new Profile((Name)asType(name, Name.class) , (int)self.get("age"));
			}
			if (clazz == Name.class) {
				return new Name((String)self.get("firstName"), (String)self.get("lastName"));
			}
			return self;
		}
	}
	/**
	 * main
	 * @param args
	 */
	public static void main(String[] args) {
		GroovyPojoJsonSample sample = new GroovyPojoJsonSample();
		sample.init();
		sample.convertPojoToJson();
		sample.convertJsonToPojo();
	}
	/**
	 * GroovyShell
	 */
	private GroovyShell shell = null;
	/**
	 * initialize GroovyShell
	 */
	public void init() {
		shell = new GroovyShell(getClass().getClassLoader(), new Binding());
	}
	/**
	 * POJO -> JSON
	 */
	public void convertPojoToJson() {
		List<Profile> profiles = new ArrayList<>();
		profiles.add(new Profile(new Name("Yasuharu", "Hayami"), 40));
		profiles.add(new Profile(new Name("康晴", "速水"), 40));
		SampleData data = new SampleData(profiles);
		File file = new File("profile.json");
		Script script = shell.parse("use(groovy.json.JsonOutput){file.text = data.toJson()}");
		Binding binding = new Binding();
		binding.setVariable("data", data);
		binding.setVariable("file", file);
		script.setBinding(binding);
		script.run();
	}
	/**
	 * JSON -> POJO
	 */
	public void convertJsonToPojo() {
		File file = new File("profile.json");
		String s = "use(" + SampleDataCategory.class.getName() +
				"){new groovy.json.JsonSlurper().parseText(file.text) as " + 
				SampleData.class.getName() + "}";
		Script script = shell.parse(s);
		Binding binding = new Binding();
		binding.setVariable("file", file);
		script.setBinding(binding);
		Object result = script.run();
		System.out.println(result.getClass().getName() + ", " + result);
	}
}