fastjson null值变换为“” _JavaScript

fastjson null值转换为“”
package test.json;

import java.sql.Date;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.serializer.JSONSerializer;
import com.alibaba.fastjson.serializer.SerializeWriter;
import com.alibaba.fastjson.serializer.SerializerFeature;
import com.alibaba.fastjson.serializer.ValueFilter;

/**
 * @author 魏斌
 * @version 创建时间：2013-2-25 下午08:47:58
 */
public class JSONDemo {

	public static String toJSONString(Object object, 
			SerializerFeature ...features) {
		SerializeWriter out = new SerializeWriter();
		String s;
		JSONSerializer serializer = new JSONSerializer(out);
		SerializerFeature arr$[] = features;
		int len$ = arr$.length;
		for (int i$ = 0; i$ < len$; i$++) {
			SerializerFeature feature = arr$[i$];
			serializer.config(feature, true);
		}

		serializer.getValueFilters().add(new ValueFilter() {
			public Object process(Object obj, String s, Object value) {
				if(null!=value) {
					if(value instanceof java.util.Date) {
						return String.format("%1$tF %1tT", value);
					}
					return value;
				}else {
					return "";
				}
			}
		});
		serializer.write(object);
		s = out.toString();
		out.close();
		return s;
	}
	
	public static void main(String[] args) {
		List list = new ArrayList();
		for (int i = 0; i <= 20; i++) {
			Map m = new HashMap();
			m.put(String.valueOf(i), null);
			m.put("date", new Date(System.currentTimeMillis()));
			list.add(m);
		}

		String json = JSONDemo.toJSONString(list);

		System.err.println(json);
		
		List<Map> parse = (List<Map>) JSON.parse(json);

		System.err.println("end ....");
	}

	
}