java使用Calendar类获得指定日期
关于指定日期的获取，是根据指定日期和当前日期相差的天数，然后使用set方法设置Calendar.DAY_OF_MONTH的值。
Calendar cal = Calendar.getInstance();
cal.set(Calendar.DAY_OF_MONTH, cal.get(Calendar.DAY_OF_MONTH) - dayPlus);
(dayPlus表示指定日期和当前日期相差的天数)
不进行set，默认是获取系统时间，初步测试没有问题，可正确获得指定日期。
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代码：
// 获得当前日期
public static String getDate() {
Calendar cal = Calendar.getInstance();
return getDate(cal);
}
// 获得日期
private static String getDate(Calendar cal) {
String v_strDate = "";
int v_intYear = cal.get(Calendar.YEAR);
int v_intMonth = cal.get(Calendar.MONTH) + 1;
int v_intDAY = cal.get(Calendar.DAY_OF_MONTH);
int v_intHOUR = cal.get(Calendar.HOUR_OF_DAY);
int v_intMINUTE = cal.get(Calendar.MINUTE);
int v_intSECOND = cal.get(Calendar.SECOND);
if (v_intDAY < 10) {
v_strDate = v_strDate + "0" + v_intDAY + "-";
}else {
v_strDate = v_strDate + v_intDAY + "-";
}
if (v_intMonth < 10) {
v_strDate = v_strDate + "0" + v_intMonth + "-";
}else {
v_strDate = v_strDate + v_intMonth + "-";
}
v_strDate = v_strDate + v_intYear + " ";
if (v_intHOUR < 10) {
v_strDate = v_strDate + "0" + v_intHOUR + ":";
}else {
v_strDate = v_strDate + v_intHOUR + ":";
}
if (v_intMINUTE < 10) {
v_strDate = v_strDate + "0" + v_intMINUTE + ":";
} else {
v_strDate = v_strDate + v_intMINUTE + ":";
}
if (v_intSECOND < 10) {
v_strDate = v_strDate + "0" + v_intSECOND;
} else {
v_strDate = v_strDate + v_intSECOND;
}
cal = null;
return v_strDate;
}
//获得当前日期与本周日相差的天数
private static 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 dayOfWeek - 1;
}
}
//获得本周一的日期
public static String getThisMondayDate() {
Calendar cal = Calendar.getInstance();
int mondayPlus = getMondayPlus();
cal.set(Calendar.DAY_OF_MONTH, cal.get(Calendar.DAY_OF_MONTH)-mondayPlus);
cal.set(Calendar.HOUR_OF_DAY, 0);
cal.set(Calendar.MINUTE, 0);
cal.set(Calendar.SECOND, 0);
return getDate(cal);
}
//获得本月1号的日期
public static String getCurrentMonthBeginDate(){
Calendar cal = Calendar.getInstance();
cal.set(Calendar.DAY_OF_MONTH, 1);
cal.set(Calendar.HOUR_OF_DAY, 0);
cal.set(Calendar.MINUTE, 0);
cal.set(Calendar.SECOND, 0);
return getDate(cal);
}
//获得上周一的日期
public static String getLastMondayDate(){
Calendar cal = Calendar.getInstance();
int dayPlus = getMondayPlus()+7;
cal.set(Calendar.DAY_OF_MONTH, cal.get(Calendar.DAY_OF_MONTH)-dayPlus);
cal.set(Calendar.HOUR_OF_DAY, 0);
cal.set(Calendar.MINUTE, 0);
cal.set(Calendar.SECOND, 0);
return getDate(cal);
}
//获得上周日的日期
public static String getLastSundayDate(){
Calendar cal = Calendar.getInstance();
int dayPlus = getMondayPlus()+1;
cal.set(Calendar.DAY_OF_MONTH, cal.get(Calendar.DAY_OF_MONTH)-dayPlus);
cal.set(Calendar.HOUR_OF_DAY, 23);
cal.set(Calendar.MINUTE, 59);
cal.set(Calendar.SECOND, 59);
return getDate(cal);
}
//获得上月1号的日期
public static String getLastMonthBeginDate(){
Calendar cal = Calendar.getInstance();
cal.set(Calendar.MONTH, cal.get(Calendar.MONTH)-1);
cal.set(Calendar.DAY_OF_MONTH,1);
cal.set(Calendar.HOUR_OF_DAY, 0);
cal.set(Calendar.MINUTE, 0);
cal.set(Calendar.SECOND, 0);
return getDate(cal);
}
//获得上个月最后一天的日期
public static String getLastMonthEndDate(){
Calendar cal = Calendar.getInstance();
cal.set(Calendar.DAY_OF_MONTH, 0);
cal.set(Calendar.HOUR_OF_DAY, 23);
cal.set(Calendar.MINUTE, 59);
cal.set(Calendar.SECOND, 59);
return getDate(cal);
}
public static void main(String[] args) {
System.out.println(getDate());
System.out.println(getThisMondayDate());
System.out.println(getCurrentMonthBeginDate());
System.out.println(getLastMondayDate());
System.out.println(getLastSundayDate());
System.out.println(getLastMonthBeginDate());
System.out.println(getLastMonthEndDate());
}
关于指定日期的获取