常用工具类1:

package com.utils;

import java.text.DateFormat;

import java.text.ParseException;

import java.text.SimpleDateFormat;

import java.util.Date;

import java.util.Map;

import javax.servlet.ServletContext;

import org.apache.struts2.ServletActionContext;

import org.apache.struts2.util.StrutsTypeConverter;

public class DateConverter extends StrutsTypeConverter {

	private DateFormat dateFormat;

	public DateConverter() {

		System.out.println("DateConverter's constructor...");

	}

	public DateFormat getDateFormat(){

		if(dateFormat == null){

			//获取当前 WEB 应用的初始化参数 pattern（即web.xml的pattern）

			ServletContext servletContext = ServletActionContext.getServletContext();

			System.out.println(servletContext);

			String pattern = servletContext.getInitParameter("pattern");

			dateFormat = new SimpleDateFormat(pattern);

		}

		return dateFormat;

	}

	@Override

	public Object convertFromString(Map context, String[] values, Class toClass) {

		System.out.println("convertFromString...");

		if(toClass == Date.class){

			if(values != null && values.length > 0){

				String value = values[0];

				try {

					return getDateFormat().parseObject(value);

				} catch (ParseException e) {

					e.printStackTrace();

				}

			}

		}

		//若没有转换成功, 则返回 values

		return values;

	}

	@Override

	public String convertToString(Map context, Object o) {

		System.out.println("convertToString...");

		if(o instanceof Date){

			Date date = (Date) o;

			return getDateFormat().format(date);

		}

		//若转换失败返回 null

		return null;

	}

}

web.xml中定义要转换的日期格式：

　　<context-param>
　　<param-name>pattern</param-name>
　　<param-value>yyyy-MM-dd hh:mm:ss</param-value>
　　</context-param>

常用工具类2：

package com.utils;

import java.text.DateFormat;

import java.text.SimpleDateFormat;

import java.util.Date;

import java.util.Map;

import com.opensymphony.xwork2.conversion.impl.DefaultTypeConverter;

public class MyDateConverter extends DefaultTypeConverter {

	private static final DateFormat[] ACCEPT_DATE_FORMATS = new DateFormat[]{

			new SimpleDateFormat("yyyy-MM-dd HH:mm:ss a"), new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"),

			new SimpleDateFormat("yyyy-MM-dd HH:mm a"), new SimpleDateFormat("yyyy-MM-dd HH:mm"),

			new SimpleDateFormat("dd/MM/yyyy"), new SimpleDateFormat("yyyy-MM-dd"), new SimpleDateFormat("yyyy/MM/dd")};

	public Object convertValue(Map context, Object value, Class toType) {

		if (toType != Date.class) {

			if (toType == String.class) {

				Date arg11 = (Date) value;

				return (new SimpleDateFormat("yyyy-MM-dd  HH:mm:ss")).format(arg11);

			} else {

				return null;

			}

		} else {

			String date = null;

			String[] params = (String[]) ((String[]) value);

			date = params[0];

			DateFormat[] arg5 = ACCEPT_DATE_FORMATS;

			int arg6 = arg5.length;

			int arg7 = 0;

			while (arg7 < arg6) {

				DateFormat format = arg5[arg7];

				try {

					return format.parse(date);

				} catch (Exception arg10) {

					++arg7;

				}

			}

			return null;

		}

	}

}