格式化日期 String-->Date 或者 Data-->String

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");  
Date date = sdf.parse("2009-11-04");//String-->Date  

String sdate = sdf.format(date );// Data-->String ===============================================================
package com.hefeng.test;
import java.text.DateFormat;
import java.text.ParsePosition;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;
public class TimeTest {
//用来全局控制 上一周，本周，下一周的周数变化
private int weeks = 0;
private int MaxDate;//一月最大天数
private int MaxYear;//一年最大天数
/**
* @param args
*/
public static void main(String[] args) {
TimeTest tt = new TimeTest();

System.out.println("得到6个月后的日期:"+tt .getAfterMonth(6);
System.out.println("获取当天日期:"+tt.getNowTime("yyyy-MM-dd"));
System.out.println("获取本周一日期:"+tt.getMondayOFWeek());
System.out.println("获取本周日的日期~:"+tt.getCurrentWeekday());
System.out.println("获取上周一日期:"+tt.getPreviousWeekday());
System.out.println("获取上周日日期:"+tt.getPreviousWeekSunday());
System.out.println("获取下周一日期:"+tt.getNextMonday());
System.out.println("获取下周日日期:"+tt.getNextSunday());
System.out.println("获得相应周的周六:"+tt.getNowTime("yyyy-MM-dd"));
System.out.println("获取本月第一天日期:"+tt.getFirstDayOfMonth());
System.out.println("获取本月最后一天日期:"+tt.getDefaultDay());
System.out.println("获取上月第一天日期:"+tt.getPreviousMonthFirst());
System.out.println("获取上月最后一天的日期:"+tt.getPreviousMonthEnd());
System.out.println("获取下月第一天日期:"+tt.getNextMonthFirst());
System.out.println("获取下月最后一天日期:"+tt.getNextMonthEnd());
System.out.println("获取本年的第一天日期:"+tt.getCurrentYearFirst());
System.out.println("获取本年最后一天日期:"+tt.getCurrentYearEnd());
System.out.println("获取去年的第一天日期:"+tt.getPreviousYearFirst());
System.out.println("获取去年的最后一天日期:"+tt.getPreviousYearEnd());
System.out.println("获取明年第一天日期:"+tt.getNextYearFirst());
System.out.println("获取明年最后一天日期:"+tt.getNextYearEnd());
System.out.println("获取本季度第一天到最后一天:"+tt.getThisSeasonTime(11));
System.out.println("获取两个日期之间间隔天数2008-12-1~2008-
.29:"+TimeTest.getTwoDay("2008-12-1","2008-9-29"));
}

/**
* 得到指定月后（前）的日期 参数传负数即可

*/

public static String getAfterMonth(int month) {
    Calendar c = Calendar.getInstance();//获得一个日历的实例  
    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");  
    Date date = null;  
    try{  
      date = sdf.parse("2009-11-04");//初始日期  
    }catch(Exception e){ 

    }  
    c.setTime(date);//设置日历时间  
    c.add(Calendar.MONTH,month);//在日历的月份上增加6个月  
    String strDate = sdf.format(c.getTime()));//的到你想要得6个月后的日期  
    return strDate;

 }


/**
* 得到二个日期间的间隔天数
*/
public static String getTwoDay(String sj1, String sj2) {
SimpleDateFormat myFormatter = new SimpleDateFormat("yyyy-MM-dd");
long day = 0;
try {
java.util.Date date = myFormatter.parse(sj1);
java.util.Date mydate = myFormatter.parse(sj2);
day = (date.getTime() - mydate.getTime()) / (24 * 60 * 60 * 1000);
} catch (Exception e) {
return "";
}
return day + "";
}
/**
* 根据一个日期，返回是星期几的字符串
*/
public static String getWeek(String sdate) {
// 再转换为时间
Date date = TimeTest.strToDate(sdate);
Calendar c = Calendar.getInstance();
c.setTime(date);
// int hour=c.get(Calendar.DAY_OF_WEEK);
// hour 中存的就是星期几了，其范围 1~7
// 1=星期日 7=星期六，其他类推
return new SimpleDateFormat("EEEE").format(c.getTime());
}
/**
* 将短时间格式字符串转换为时间 yyyy-MM-dd
*/
public static Date strToDate(String strDate) {
SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd");
ParsePosition pos = new ParsePosition(0);
Date strtodate = formatter.parse(strDate, pos);
return strtodate;
}
/**
* 两个时间之间的天数
*
* @param date1
* @param date2
* @return
*/
public static long getDays(String date1, String date2) {
if (date1 == null || date1.equals(""))
return 0;
if (date2 == null || date2.equals(""))
return 0;
// 转换为标准时间
SimpleDateFormat myFormatter = new SimpleDateFormat("yyyy-MM-dd");
java.util.Date date = null;
java.util.Date mydate = null;
try {
date = myFormatter.parse(date1);
mydate = myFormatter.parse(date2);
} catch (Exception e) {
}
long day = (date.getTime() - mydate.getTime()) / (24 * 60 * 60 * 1000);
return day;
}
// 计算当月最后一天,返回字符串
public String getDefaultDay(){
String str = "";
SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd");
Calendar lastDate = Calendar.getInstance();
lastDate.set(Calendar.DATE,1);//设为当前月的1 号
lastDate.add(Calendar.MONTH,1);//加一个月，变为下月的1 号
lastDate.add(Calendar.DATE,-1);//减去一天，变为当月最后一天
str=sdf.format(lastDate.getTime());
return str;
}
// 上月第一天
public String getPreviousMonthFirst(){
String str = "";
SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd");
Calendar lastDate = Calendar.getInstance();
lastDate.set(Calendar.DATE,1);//设为当前月的1 号
lastDate.add(Calendar.MONTH,-1);//减一个月，变为下月的1 号
//lastDate.add(Calendar.DATE,-1);//减去一天，变为当月最后一天
str=sdf.format(lastDate.getTime());
return str;
}
//获取当月第一天
public String getFirstDayOfMonth(){
String str = "";
SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd");
Calendar lastDate = Calendar.getInstance();
lastDate.set(Calendar.DATE,1);//设为当前月的1 号
str=sdf.format(lastDate.getTime());
return str;
}
// 获得本周星期日的日期
public String getCurrentWeekday() {
weeks = 0;
int mondayPlus = this.getMondayPlus();
GregorianCalendar currentDate = new GregorianCalendar();
currentDate.add(GregorianCalendar.DATE, mondayPlus+6);
Date monday = currentDate.getTime();
DateFormat df = DateFormat.getDateInstance();
String preMonday = df.format(monday);
return preMonday;
}
//获取当天时间
public String getNowTime(String dateformat){
Date now = new Date();
SimpleDateFormat dateFormat = new SimpleDateFormat(dateformat);//可
以方便
地修改日期格式
String hehe = dateFormat.format(now);
return hehe;
}
// 获得当前日期与本周日相差的天数
private int getMondayPlus() {
Calendar cd = Calendar.getInstance();
// 获得今天是一周的第几天，星期日是第一天，星期二是第二天......
int dayOfWeek = cd.get(Calendar.DAY_OF_WEEK)-1; //因为按中国礼拜一
作为第一
天所以这里减1
if (dayOfWeek == 1) {
return 0;
} else {
return 1 - dayOfWeek;
}
}
//获得本周一的日期
public String getMondayOFWeek(){
weeks = 0;
int mondayPlus = this.getMondayPlus();
GregorianCalendar currentDate = new GregorianCalendar();
currentDate.add(GregorianCalendar.DATE, mondayPlus);
Date monday = currentDate.getTime();
DateFormat df = DateFormat.getDateInstance();
String preMonday = df.format(monday);
return preMonday;
}
//获得相应周的周六的日期
public String getSaturday() {
int mondayPlus = this.getMondayPlus();
GregorianCalendar currentDate = new GregorianCalendar();
currentDate.add(GregorianCalendar.DATE, mondayPlus + 7 * weeks + 6);
Date monday = currentDate.getTime();
DateFormat df = DateFormat.getDateInstance();
String preMonday = df.format(monday);
return preMonday;
}
// 获得上周星期日的日期
public String getPreviousWeekSunday() {
weeks=0;
weeks--;
int mondayPlus = this.getMondayPlus();
GregorianCalendar currentDate = new GregorianCalendar();
currentDate.add(GregorianCalendar.DATE, mondayPlus+weeks);
Date monday = currentDate.getTime();
DateFormat df = DateFormat.getDateInstance();
String preMonday = df.format(monday);
return preMonday;
}
// 获得上周星期一的日期
public String getPreviousWeekday() {
weeks--;
int mondayPlus = this.getMondayPlus();
GregorianCalendar currentDate = new GregorianCalendar();
currentDate.add(GregorianCalendar.DATE, mondayPlus + 7 * weeks);
Date monday = currentDate.getTime();
DateFormat df = DateFormat.getDateInstance();
String preMonday = df.format(monday);
return preMonday;
}
// 获得下周星期一的日期
public String getNextMonday() {
weeks++;
int mondayPlus = this.getMondayPlus();
GregorianCalendar currentDate = new GregorianCalendar();
currentDate.add(GregorianCalendar.DATE, mondayPlus + 7);
Date monday = currentDate.getTime();
DateFormat df = DateFormat.getDateInstance();
String preMonday = df.format(monday);
return preMonday;
}
// 获得下周星期日的日期
public String getNextSunday() {
int mondayPlus = this.getMondayPlus();
GregorianCalendar currentDate = new GregorianCalendar();
currentDate.add(GregorianCalendar.DATE, mondayPlus + 7+6);
Date monday = currentDate.getTime();
DateFormat df = DateFormat.getDateInstance();
String preMonday = df.format(monday);
return preMonday;
}
private int getMonthPlus(){
Calendar cd = Calendar.getInstance();
int monthOfNumber = cd.get(Calendar.DAY_OF_MONTH);
cd.set(Calendar.DATE, 1);//把日期设置为当月第一天
cd.roll(Calendar.DATE, -1);//日期回滚一天，也就是最后一天
MaxDate=cd.get(Calendar.DATE);
if(monthOfNumber == 1){
return -MaxDate;
}else{
return 1-monthOfNumber;
}
}
//获得上月最后一天的日期
public String getPreviousMonthEnd(){
String str = "";
SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd");
Calendar lastDate = Calendar.getInstance();
lastDate.add(Calendar.MONTH,-1);//减一个月
lastDate.set(Calendar.DATE, 1);//把日期设置为当月第一天
lastDate.roll(Calendar.DATE, -1);//日期回滚一天，也就是本月最后一天
str=sdf.format(lastDate.getTime());
return str;
}
//获得下个月第一天的日期
public String getNextMonthFirst(){
String str = "";
SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd");
Calendar lastDate = Calendar.getInstance();
lastDate.add(Calendar.MONTH,1);//减一个月
lastDate.set(Calendar.DATE, 1);//把日期设置为当月第一天
str=sdf.format(lastDate.getTime());
return str;
}
//获得下个月最后一天的日期
public String getNextMonthEnd(){
String str = "";
SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd");
Calendar lastDate = Calendar.getInstance();
lastDate.add(Calendar.MONTH,1);//加一个月
lastDate.set(Calendar.DATE, 1);//把日期设置为当月第一天
lastDate.roll(Calendar.DATE, -1);//日期回滚一天，也就是本月最后一天
str=sdf.format(lastDate.getTime());
return str;
}
//获得明年最后一天的日期
public String getNextYearEnd(){
String str = "";
SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd");
Calendar lastDate = Calendar.getInstance();
lastDate.add(Calendar.YEAR,1);//加一个年
lastDate.set(Calendar.DAY_OF_YEAR, 1);
lastDate.roll(Calendar.DAY_OF_YEAR, -1);
str=sdf.format(lastDate.getTime());
return str;
}
//获得明年第一天的日期
public String getNextYearFirst(){
String str = "";
SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd");
Calendar lastDate = Calendar.getInstance();
lastDate.add(Calendar.YEAR,1);//加一个年
lastDate.set(Calendar.DAY_OF_YEAR, 1);
str=sdf.format(lastDate.getTime());
return str;
}
//获得本年有多少天
private int getMaxYear(){
Calendar cd = Calendar.getInstance();
cd.set(Calendar.DAY_OF_YEAR,1);//把日期设为当年第一天
cd.roll(Calendar.DAY_OF_YEAR,-1);//把日期回滚一天。
int MaxYear = cd.get(Calendar.DAY_OF_YEAR);
return MaxYear;
}
private int getYearPlus(){
Calendar cd = Calendar.getInstance();
int yearOfNumber = cd.get(Calendar.DAY_OF_YEAR);//获得当天是一年中的第几天
cd.set(Calendar.DAY_OF_YEAR,1);//把日期设为当年第一天
cd.roll(Calendar.DAY_OF_YEAR,-1);//把日期回滚一天。
int MaxYear = cd.get(Calendar.DAY_OF_YEAR);
if(yearOfNumber == 1){
return -MaxYear;
}else{
return 1-yearOfNumber;
}
}
//获得本年第一天的日期
public String getCurrentYearFirst(){
int yearPlus = this.getYearPlus();
GregorianCalendar currentDate = new GregorianCalendar();
currentDate.add(GregorianCalendar.DATE,yearPlus);
Date yearDay = currentDate.getTime();
DateFormat df = DateFormat.getDateInstance();
String preYearDay = df.format(yearDay);
return preYearDay;
}
//获得本年最后一天的日期 *
public String getCurrentYearEnd(){
Date date = new Date();
SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy");//可以方
便地修
改日期格式
String years = dateFormat.format(date);
return years+"-12-31";
}

//获得上年第一天的日期 *
public String getPreviousYearFirst(){
Date date = new Date();
SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy");//可以方
便地修
改日期格式
String years = dateFormat.format(date); int years_value = Integer.parseInt
(years);
years_value--;
return years_value+"-1-1";
}
//获得上年最后一天的日期
public String getPreviousYearEnd(){
weeks--;
int yearPlus = this.getYearPlus();
GregorianCalendar currentDate = new GregorianCalendar();
currentDate.add(GregorianCalendar.DATE,yearPlus+MaxYear*weeks+(MaxYear-1));
Date yearDay = currentDate.getTime();
DateFormat df = DateFormat.getDateInstance();
String preYearDay = df.format(yearDay);
getThisSeasonTime(11);
return preYearDay;
}
//获得本季度
public String getThisSeasonTime(int month){
int array[][] = {{1,2,3},{4,5,6},{7,8,9},{10,11,12}};
int season = 1;
if(month>=1&&month<=3){
season = 1;
}
if(month>=4&&month<=6){
season = 2;
}
if(month>=7&&month<=9){
season = 3;
}
if(month>=10&&month<=12){
season = 4;
}
int start_month = array[season-1][0];
int end_month = array[season-1][2];
Date date = new Date();
SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy");//可以方
便地修
改日期格式
String years = dateFormat.format(date);
int years_value = Integer.parseInt(years);
int start_days =1;//years+"-"+String.valueOf(start_month)+"-
";//getLastDayOfMonth(years_value,start_month);
int end_days = getLastDayOfMonth(years_value,end_month);
String seasonDate =
years_value+"-"+start_month+"-"+start_days+";"+years_value+"-"+end_month+"-"+end_days;
return seasonDate;
}
/**
* 获取某年某月的最后一天
* @param year 年
* @param month 月
* @return 最后一天
*/
private int getLastDayOfMonth(int year, int month) {
if (month == 1 || month == 3 || month == 5 || month == 7 || month == 8
|| month == 10 || month == 12) {
return 31;
}
if (month == 4 || month == 6 || month == 9 || month == 11) {
return 30;
}
if (month == 2) {
if (isLeapYear(year)) {
return 29;
} else {
return 28;
}
}
return 0;
}
/**
* 是否闰年
* @param year 年
* @return
*/
public boolean isLeapYear(int year) {
return (year % 4 == 0 && year % 100 != 0) || (year % 400 == 0);
}