Java 获取指定日期的实现方法总结

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);
}