根据时间或时间字符串获取星期几

1、根据时间：

public class getWeek {
public static String getWeek(Date date){
SimpleDateFormat sdf = new SimpleDateFormat("EEEE");
String week = sdf.format(date);
return week;
}

public static String getWeek2(Date date){
String[] weeks = {"星期日","星期一","星期二","星期三","星期四","星期五","星期六"};
Calendar cal = Calendar.getInstance();
cal.setTime(date);
int week_index = cal.get(Calendar.DAY_OF_WEEK) - 1;
if(week_index<0){
week_index = 0;
}
return weeks[week_index];
}

public static void main(String[] args) {
Date data = new Date();
System.out.println(getWeek(data));
System.out.println(getWeek2(data));
}
}

2、根据字符串：

/**
* <pre>
* 根据指定的日期字符串获取星期几
* </pre>
*
* @param strDate 指定的日期字符串(yyyy-MM-dd 或 yyyy/MM/dd)
* @return week
*         星期几(MONDAY,TUESDAY,WEDNESDAY,THURSDAY,FRIDAY,SATURDAY,SUNDAY)
*/
public static String getWeekByDateStr(String strDate)
{
int year = Integer.parseInt(strDate.substring(0, 4));
int month = Integer.parseInt(strDate.substring(5, 7));
int day = Integer.parseInt(strDate.substring(8, 10));

Calendar c = Calendar.getInstance();

c.set(Calendar.YEAR, year);
c.set(Calendar.MONTH, month - 1);
c.set(Calendar.DAY_OF_MONTH, day);

String week = "";
int weekIndex = c.get(Calendar.DAY_OF_WEEK);

switch (weekIndex)
{
case 1:
week = "SUNDAY";
break;
case 2:
week = "MONDAY";
break;
case 3:
week = "TUESDAY";
break;
case 4:
week = "WEDNESDAY";
break;
case 5:
week = "THURSDAY";
break;
case 6:
4000
week = "FRIDAY";
break;
case 7:
week = "SATURDAY";
break;
}
return week;
}