DateUtil.java

package com.keju.maomao.util;

import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;

/**
 * 日期处理工具类
 * @author Zhoujun
 *	说明：对日期格式的格式化与转换操作等一系列操作
 */
public class DateUtil {
	
	/**
	 * 字符串转换成日期  yyyy-MM-dd HH:mm:ss
	 * @param strFormat  格式定义 如：yyyy-MM-dd HH:mm:ss
	 * @param dateValue 日期对象
	 * @return
	 */
	public static Date stringToDate(String strFormat, String dateValue) {
		if (dateValue == null)
			return null;
		if (strFormat == null)
			strFormat = "yyyy-MM-dd HH:mm:ss";
		
		SimpleDateFormat dateFormat = new SimpleDateFormat(strFormat);
		Date newDate = null;
		try {
			newDate = dateFormat.parse(dateValue);
		} catch (ParseException pe) {
			newDate = null;
		}
		return newDate;
	} 
	/**
	 * 日期转成字符串
	 * @param strFormat 格式定义 如：yyyy-MM-dd HH:mm:ss
	 * @param date 日期字符串
	 * @return
	 */
	public static String dateToString(String strFormat, Date date){
		SimpleDateFormat dateFormat = new SimpleDateFormat(strFormat);
		return dateFormat.format(date);
	}

	
	/**
	 * 计算两个日期间隔天数
	 * @param begin
	 * @param end
	 * @return
	 */
	public static int countDays(Date begin, Date end) {
		int days = 0;
		Calendar c_b = Calendar.getInstance();
		Calendar c_e = Calendar.getInstance();
		c_b.setTime(begin);
		c_e.setTime(end);
		while (c_b.before(c_e)) {
			days++;
			c_b.add(Calendar.DAY_OF_YEAR, 1);
		}
		return days;
	}
	
	/**
	 * 获取最近的时间
	 * @param time
	 * @return
	 */
	public static String getNearTime(String str1){
			String result = "";
	        DateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");  
	        Date one;  
	        Date two;  
	        long day = 0;  
	        long hour = 0;  
	        long min = 0;  
	        long sec = 0;  
	        try {  
	            one = df.parse(str1);  
	            two = new Date();
	            long time1 = one.getTime();  
	            long time2 = two.getTime();  
	            long diff ;  
	            if(time1<time2) {  
	                diff = time2 - time1;  
	            } else {  
	                diff = time1 - time2;  
	            }  
	            day = diff / (24 * 60 * 60 * 1000);  
	            hour = (diff / (60 * 60 * 1000) - day * 24);  
	            min = ((diff / (60 * 1000)) - day * 24 * 60 - hour * 60);  
	            sec = (diff/1000-day*24*60*60-hour*60*60-min*60); 
	            System.out.println(day+"天"+hour+"小时"+min+"分钟"+sec+"秒");
	            long m = day*24 * 60+hour*60+min;
	            
				if(m<=1){
					result = "一分钟前";
				}else if(m>1 && m<=5){
					result = "五分钟前";
				}else if(m>5 && m<=30){
					result = "半小时前";
				}else if(m>30 && m<=60){
					result = "一小时前";
				}else if(m>60 && m<=60*2){
					result = "两小时前";
				}else if(m>60*2 && m<=60*24){
					result = "一天前";
				}else if(m>60*24 && m<=60*24*2){
					result = "两天前";
				}else if(m>60*24*2 && m<=60*24*7){
					result = "一星期前";
				}else if(m>60*24*7 && m<=60*24*30){
					result = "一个月前";
				}else if(m>60*24*30 && m<=60*24*30*6){
					result = "六个月前";
				}else if(m>60*24*30*6){
					result = "很久以前";
				}
	            day = diff / (24 * 60 * 60 * 1000);  
	            hour = (diff / (60 * 60 * 1000) - day * 24);  
	            min = ((diff / (60 * 1000)) - day * 24 * 60 - hour * 60);  
	            sec = (diff/1000-day*24*60*60-hour*60*60-min*60);  
	        } catch (ParseException e) {  
	        }  
	        return result;  
	    }
	
	/**
	 * 如果是昨天就显示年月日，今天的只显示时间；
	 * 
	 * @param time
	 * @return
	 */
	public static String getConversationTime(String str1) {
		String result = "";
		DateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
		Date one;
		Date two;
		try {
			one = df.parse(str1);
			two = new Date();

			if (one.getYear() == two.getYear()
					&& one.getMonth() == two.getMonth()
					&& one.getDay() == two.getDay()) {
				result = "今天  " + dateToString("HH:mm", one);
				;
			} else {
				result = dateToString("yyyy-MM-dd", one);
			}
		} catch (ParseException e) {
		}
		return result;
	}
}