WicketでJSONデータを返却する(json-lib編)

mavenの指定

<dependency>
	<groupId>net.sf.json-lib</groupId>
	<artifactId>json-lib</artifactId>
	<version>2.3</version>
	<classifier>jdk15</classifier>
</dependency>
<dependency>
	<groupId>commons-lang</groupId>
	<artifactId>commons-lang</artifactId>
	<version>2.4</version>
</dependency>

json-libではclassifierを忘れずに。
あと、DateクラスをISO8601形式の文字列に変換するためにcommons-langも使ってます。

JsonLibPage.java

package jp.tanamon.wicket;

import java.util.ArrayList;
import java.util.Date;
import java.util.List;

import net.sf.json.JSONArray;
import net.sf.json.JsonConfig;
import net.sf.json.processors.JsonValueProcessor;

import org.apache.commons.lang.time.DateFormatUtils;
import org.apache.commons.lang.time.DateUtils;
import org.apache.wicket.IRequestTarget;
import org.apache.wicket.RequestCycle;
import org.apache.wicket.markup.html.WebPage;

public class JsonLibPage extends WebPage {
	public JsonLibPage() {

		getRequestCycle().setRequestTarget(new IRequestTarget() {

			public void detach(RequestCycle requestCycle) {
				// nothing to do here
			}

			public void respond(RequestCycle requestCycle) {
				requestCycle.getResponse().setContentType("application/json; charset=utf-8");

				List<JsonData> list = new ArrayList<JsonData>();
				list.add(new JsonData("All Day Event", new Date(), null));
				list.add(new JsonData("Long Event", DateUtils.setDays(new Date(), 2), DateUtils.setDays(new Date(), 10)));

				// POJO to JsonObject
				JsonConfig config = new JsonConfig();
				config.registerJsonValueProcessor(java.util.Date.class, new DateJsonValueProcessor());
				JSONArray jsonArray = JSONArray.fromObject(list, config);

				// JsonObject to String
				requestCycle.getResponse().write(jsonArray.toString());
			}
		});
	}

	public class DateJsonValueProcessor implements JsonValueProcessor {
		public Object processArrayValue(Object value, JsonConfig config) {
			return process((Date) value, config);
		}

		public Object processObjectValue(String key, Object value, JsonConfig config) {
			return process((Date) value, config);
		}

		private Object process(Date date, JsonConfig config) {
			if (date == null) {
				return null;
			}
			return DateFormatUtils.ISO_DATETIME_TIME_ZONE_FORMAT.format(date);
		}
	}

	public class JsonData {
		private String title;

		private Date start;

		private Date end;

		public JsonData(String title, Date start, Date end) {
			this.title = title;
			this.start = start;
			this.end = end;
		}

		public String getTitle() {
			return title;
		}

		public void setTitle(String title) {
			this.title = title;
		}

		public Date getStart() {
			return start;
		}

		public void setStart(Date start) {
			this.start = start;
		}

		public Date getEnd() {
			return end;
		}

		public void setEnd(Date end) {
			this.end = end;
		}
	}
}

出力内容

[{"end":null,"start":"2009-12-08T11:05:44+09:00","title":"All Day Event"},{"end":"2009-12-10T11:05:44+09:00","start":"2009-12-02T11:05:44+09:00","title":"Long Event"}]

メモ

• Dateクラスは普通に変換させると残念なことになるのでJsonValueProcessorを使って変換させる必要がある
• POJOの解析にはcommons-beanutilsを使っているので、setter/getterが必要
• アノテーションとかそういうものはない