获取某月的天数的方法是什么？--------------急救！

      Calendar c = Calendar.getInstance();
      //设置为该月，例如08年1月，日期随意
       c.set(2008,0,1);
      //获得该月的日期
       int max = c.getActualMaximum(Calendar.DATE);

int maxDay = calendar.getActualMaximum(Calendar.DAY_OF_MONTH);

SimpleDateFormat 用这个类！用起相当舒服！
import java.text.SimpleDateFormat;
import java.util.Date;
public class Test {

public static void main(String[] args) {
Date date=new Date();

SimpleDateFormat sdf=new SimpleDateFormat ("yyyy年MM月dd天");

System.out.println(sdf.format(date));
}
}

斑竹说的应该是得到一年中间一个月天数最多的那个月的天数----31
好象与LZ的要求不怎么符合...LZ要的是输入月份,得到该月的实际天数.
问LZ是吧?

int maxDay=new GregorianCalendar().getActualMaximum(Calendar.DATE);
这就是当前月的最大天数。

没错啦，Calendar的getActualMaximum方法。像今年的2月，返回的就是29天

getInstance()里面的3个参数最后一位是什么意思呢？

/**
* Title: 时间格式转化与计算
* Copyright: Copyright (c) 2004
* Company: www.code-park.com
* @author 网络信息部范庆丰
* @version 1.0
*/package www.fqf.cn.com;import java.util.Calendar;
import java.util.Date;
import java.text.*;
import java.util.GregorianCalendar;public class DateTime {
 public DateTime() {
 } /**
 * 取得系统当前时间
 * @return String yyyy-mm-dd
 */
 public String getCurrentDate() {
 Calendar rightNow = Calendar.getInstance();
 int year = rightNow.get(rightNow.YEAR);
 int month = rightNow.get(rightNow.MONTH) + 1;
 int day = rightNow.get(rightNow.DATE);
 return year + "-" + month + "-" + day;
 } /**
 * 取得系统当前时间
 * @return String yyyy年mm月dd日
 */
 public String getCurrentDate1() {
 Calendar rightNow = Calendar.getInstance();
 int year = rightNow.get(rightNow.YEAR);
 int month = rightNow.get(rightNow.MONTH) + 1;
 int day = rightNow.get(rightNow.DATE);
 return year + "年" + month + "月" + day + "日";
 } /**
 * 取得系统当前时间
 * @return String yyyymmdd
 */
 public String getCurrentDate2() {
 Calendar rightNow = Calendar.getInstance();
 int year = rightNow.get(rightNow.YEAR);
 int month = rightNow.get(rightNow.MONTH) + 1;
 int day = rightNow.get(rightNow.DATE);
 return year + "" + month + "" + day;
 } /**
 * 取得系统当前时间
 * @return String yyyy-mm
 */
 public String getCurrentDate3() {
 Calendar rightNow = Calendar.getInstance();
 int year = rightNow.get(rightNow.YEAR);
 int month = rightNow.get(rightNow.MONTH) + 1;
 //int day = rightNow.get(rightNow.DATE);
 return year + "-" + month;
 } /**
 * 取得系统当前时间
 * @return String yyyyMMddhhmmss
 */
 public String getCurrentDate4() {
 Calendar c = Calendar.getInstance();
 c.add(c.SECOND, 0); return "" + c.get(c.YEAR) + "" + (c.get(c.MONTH) + 1) + "" + c.get(c.DATE)+""+c.get(c.HOUR_OF_DAY)+""+c.get(c.MINUTE)+""+c.get(c.SECOND);} /**
 * 取得系统当前时间
 * @return String yyyy-MM-dd hh:mm:ss
 */
/* public String getCurrentDate5() {
 SimpleDateFormat simpleDateFormat =new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");
 java.util.Date date = new java.util.Date();
 String time = simpleDateFormat.format(date);
 return time;
 }
*/
/**
* 取得系统当前时间
* @return String yyyy-MM-dd hh:mm:ss
*/ public String getCurrentDate5(){
 Calendar c = Calendar.getInstance();
 c.add(c.SECOND, 0);
 return "" + c.get(c.YEAR) + "-" + (c.get(c.MONTH) + 1) + "-" + c.get(c.DATE)+" "+c.get(c.HOUR_OF_DAY)+":"+c.get(c.MINUTE)+":"+c.get(c.SECOND);
 } /**
 * 取得系统当前时间常用于订单号
 * @return String yyyyMMddhhmmss
 */
 public String getCurrentDate6() {
 Calendar c = Calendar.getInstance();
 c.add(c.SECOND, 0);
 String year=c.get(c.YEAR)+"";
 return "" + year.subSequence(2,year.length())+ "" + (c.get(c.MONTH) + 1) + "" + c.get(c.DATE)+"-"+c.get(c.HOUR_OF_DAY)+""+c.get(c.MINUTE)+""+c.get(c.SECOND)+"-"+c.get(c.MILLISECOND); } //YYYYMMDD
 public String getCurrentDate7() {
 Calendar c = Calendar.getInstance();
 c.add(c.SECOND, 0);
 String year=c.get(c.YEAR)+"";
 int month=c.get(c.MONTH) + 1;
 String strmonth=month+"";
 if(month<10){
 strmonth="0"+month;
 }
 int day=c.get(c.DATE);
 String strday=day+"";
 if(day<10){
 strday="0"+day;
 }
 return "" + year+ "" + strmonth + "" + strday; }
 //hhmmsswww
 public String getCurrentDate8() {
 Calendar c = Calendar.getInstance();
 c.add(c.SECOND, 0);
 int hh=c.get(c.HOUR_OF_DAY);
 String strhh=hh+"";
 if(hh<10){
 strhh="0"+hh;
 }
 int mm=c.get(c.MINUTE);
 String strmm=mm+"";
 if(mm<10){
 strmm="0"+mm;
 }
 int ss=c.get(c.SECOND);
 String strss=ss+"";
 if(ss<10){
 strss="0"+ss;
 }
 int www=c.get(c.MILLISECOND);
 String strwww=www+"";
 if(www<10){
 strwww="00"+www;
 }if(9<www&&www<100){
 strwww="0"+www;
 } return strhh+""+strmm+""+strss+""+strwww; } /**
 * 取得系统当前时间前n个月的相对应的一天
 * @param n int
 * @return String yyyy-mm-dd
 */
 public String getNMonthBeforeCurrentDay(int n) {
 Calendar c = Calendar.getInstance();
 c.add(c.MONTH, -n);
 return "" + c.get(c.YEAR) + "-" + (c.get(c.MONTH) + 1) + "-" + c.get(c.DATE); } /**
 * 取得系统当前时间后n个月的相对应的一天
 * @param n int
 * @return String yyyy-mm-dd
 */
 public String getNMonthAfterCurrentDay(int n) {
 Calendar c = Calendar.getInstance();
 c.add(c.MONTH, n);
 return "" + c.get(c.YEAR) + "-" + (c.get(c.MONTH) + 1) + "-" + c.get(c.DATE); } /**
 * 取得系统当前时间前n天
 * @param n int
 * @return String yyyy-mm-dd
 */
 public String getNDayBeforeCurrentDate(int n) {
 Calendar c = Calendar.getInstance();
 c.add(c.DAY_OF_MONTH, -n);
 return "" + c.get(c.YEAR) + "-" + (c.get(c.MONTH) + 1) + "-" + c.get(c.DATE);
 } /**
 * 取得系统当前时间后n天
 * @param n int
 * @return String yyyy-mm-dd
 */
 public String getNDayAfterCurrentDate(int n) {
 Calendar c = Calendar.getInstance();
 c.add(c.DAY_OF_MONTH, n);
 return "" + c.get(c.YEAR) + "-" + (c.get(c.MONTH) + 1) + "-" + c.get(c.DATE);
 }
 public String getNDayAfterCurrentDate1(int n) {
 Calendar c = Calendar.getInstance();
 c.add(c.DAY_OF_MONTH, n);
 return "" + c.get(c.YEAR) + "-" + (c.get(c.MONTH) + 1) + "-" + c.get(c.DATE)+" "+c.get(c.HOUR_OF_DAY)+":"+c.get(c.MINUTE)+":"+c.get(c.SECOND);
 }
 //---------------------------------------------------------------------
 //取过去一个时间对应的系统当年的一天
 public String getCurrentDateAfterPastDate(String sPastDate) {
 if (sPastDate != null && !sPastDate.equals("")) {
 Date date = switchStringToDate(sPastDate);
 Calendar c = Calendar.getInstance();
 c.setTime(date);
 int iPastYear = c.get(c.YEAR);
 Calendar c1 = Calendar.getInstance();
 int iCurrentYear = c1.get(c1.YEAR);
 c.add(c.YEAR, iCurrentYear - iPastYear);
 return "" + c.get(c.YEAR) + "-" + (c.get(c.MONTH) + 1) + "-" +
 c.get(c.DATE);
 }
 else {
 return null;
 }
 } /**
 * 将一个日期字符串转化成日期
 * @param sDate String
 * @return Date yyyy-mm-dd
 */
 public Date switchStringToDate(String sDate) {
 Date date = null;
 try {
 SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd");
 date = df.parse(sDate); }
 catch (Exception e) {
 System.out.println("日期转换失败:" + e.getMessage());
 }
 return date;
 } /**
 * 输入两个字符串型的日期，比较两者的大小
 * @param fromDate String
 * @param toDate String
 * @return boolean before为true
 */
 public boolean compareTwoDateBigOrSmall(String fromDate, String toDate) {
 Date dateFrom = this.switchStringToDate(fromDate);
 Date dateTo = this.switchStringToDate(toDate);
 if (dateFrom.before(dateTo)) {
 return true;
 }
 else {
 return false;
 }
 }

/**
 * 将一个日期字符串转化成Calendar
 * @param sDate String
 * @return Calendar
 */
 public Calendar switchStringToCalendar(String sDate) {
 Date date = switchStringToDate(sDate);
 Calendar c = Calendar.getInstance();
 c.setTime(date);
 return c;
 } /**
 * 将一个日期转化成Calendar
 * @param date Date
 * @return Calendar
 */
 public Calendar switchStringToCalendar(Date date) {
 Calendar c = Calendar.getInstance();
 c.setTime(date);
 return c;
 } public String string2Date(String dateString)
 throws java.lang.Exception {
 /*DateFormat dateFormat;
 dateFormat = new SimpleDateFormat("yyyy-MM-dd kk:mm:ss");
 dateFormat.setLenient(false);
 java.util.Date timeDate = dateFormat.parse(dateString);//util类型
 //java.sql.Date dateTime = new java.sql.Date(timeDate.getTime());//sql类型
 java.sql.Timestamp dateTime = new java.sql.Timestamp(timeDate.getTime());//Timestamp类型
 */
 SimpleDateFormat newk = new SimpleDateFormat ("yyyy.MM.dd hh:mm:ss");
 SimpleDateFormat old = new SimpleDateFormat("MMM dd hh:mm:ss yyyy"); String strDate = "Mar 22 00:42:00 2002";
 Date d = old.parse(strDate);
 System.out.println(newk.format(d)); return newk.format(d);
 } /**
 * 取得某个时间前n个月的相对应的一天
 * @param sDate String
 * @param n int
 * @return String yyyy-mm-dd
 */
 public String getNMonthBeforeOneDay(String sDate, int n) {
 Calendar c = switchStringToCalendar(sDate);
 c.add(c.MONTH, -n);
 return "" + c.get(c.YEAR) + "-" + (c.get(c.MONTH) + 1) + "-" + c.get(c.DATE); } //取得某个时间后n个月的相对应的一天
 public String getNMonthAfterOneDay(String sDate, int n) {
 Calendar c = switchStringToCalendar(sDate);
 c.add(c.MONTH, n);
 return "" + c.get(c.YEAR) + "-" + (c.get(c.MONTH) + 1) + "-" + c.get(c.DATE); } //取得某个时间前n天,格式为yyyy-mm-dd
 public String getNDayBeforeOneDate(String sDate, int n) {
 Calendar c = switchStringToCalendar(sDate);
 c.add(c.DAY_OF_MONTH, -n);
 return "" + c.get(c.YEAR) + "-" + (c.get(c.MONTH) + 1) + "-" + c.get(c.DATE);
 } //取得某个时间后n天,格式为yyyy-mm-dd
 public String getNDayAfterOneDate(String sDate, int n) {
 Calendar c = switchStringToCalendar(sDate);
 c.add(c.DAY_OF_MONTH, n);
 return "" + c.get(c.YEAR) + "-" + (c.get(c.MONTH) + 1) + "-" + c.get(c.DATE);
 } //判断系统当前时间是不是润年
 public boolean isRunNian() {
 java.util.Calendar rightNow = java.util.Calendar.getInstance();
 int year = rightNow.get(rightNow.YEAR);
 if (0 == year % 4 && (year % 100 != 0 || year % 400 == 0)) {
 return true;
 }
 else {
 return false;
 } }
 //
 public int getWeek(String date){
 String[] a=date.split("-");
 int year=Integer.parseInt(a[0]);
 int month=Integer.parseInt(a[1])-1;
 int day=Integer.parseInt(a[2]);
 GregorianCalendar d=new GregorianCalendar();
 d.set(year,month,day);
 int weekday=d.get(Calendar.DAY_OF_WEEK);
 //System.out.println(weekday-1);
 return weekday-1;
 }
 public String[] getWeekdays(String date){
 int atweek= getWeek(date);
 //System.out.println(getNDayBeforeCurrentDate(atweek));
 String[] days=new String[7];
 for(int i=0;i<7;i++){
 days[i]=getNDayAfterOneDate(getNDayBeforeOneDate(date,atweek-1),i);
 }
// for(int i=0;i<7;i++){
// System.out.println("==="+days[i]);
// }
 return days;
 }
 public static void main(String args[]) {
 DateTime a = new DateTime();
 try{
 a.getWeekdays("2008-12-30");
 System.out.println(a.getNDayAfterCurrentDate(1));
 System.out.println(a.getNDayAfterCurrentDate(0));
 System.out.println(a.compareTwoDateBigOrSmall("2005-12-27 11:01:45.0","2005-12-10 13:16:58.0"));
 }catch(Exception e){System.err.println();} }
}

调试易

获取某月的天数的方法是什么？--------------急救！

解决方案 »