java.util.Date 转json 时格式问题
在将java.util.Date 类型字段转为json时，获取时取到的为[object object]，解决方法为：在讲对象转化为json格式是添加自定义的日期格式转化类，具体代码如下：

public class DateJsonValueProcessor implements JsonValueProcessor {
	private String format = "yyyy-MM-dd";

	public DateJsonValueProcessor() {
	}

	public DateJsonValueProcessor(String format) {
		this.format = format;
	}

	public Object processArrayValue(Object value, JsonConfig jsonConfig) {
		String[] obj = {};
		if(value!=null)
		{
			if (value instanceof Date[]) {
				SimpleDateFormat sf = new SimpleDateFormat(format);
				Date[] dates = (Date[]) value;
				obj = new String[dates.length];
				for (int i = 0; i < dates.length; i++) {
					obj[i] = sf.format(dates[i]);
				}
			}
		}
		return obj;
	}

	public Object processObjectValue(String key, Object value,
			JsonConfig jsonConfig) {
		if(value!=null)
		{
			if (value instanceof Date) {
				String str = new SimpleDateFormat(format).format((Date) value);
				return str;
			}
		}
		return value;
	}

	public String getFormat() {
		return format;
	}

	public void setFormat(String format) {
		this.format = format;
	}

}

使用方法：

JsonConfig jsonConfig = new JsonConfig();
jsonConfig.registerJsonValueProcessor(java.util.Date.class, new DateJsonValueProcessor("yyyy-MM-dd"));

将json返回客户端

HttpServletResponse response = this.getHttpResponse();
		response.setContentType("text/plain;charset=UTF-8");
		response.setHeader("Cache-Control","no-cache");
		JsonConfig jsonConfig = new JsonConfig();
		jsonConfig.registerJsonValueProcessor(Date.class, new DateJsonValueProcessor("yyyy-MM-dd"));
		try {
			response.getWriter().print(JSONObject.fromObject(conObj,jsonConfig));
		} catch (Exception e) {
			e.printStackTrace();
		}
		return null;