import java.util.Calendar;
import java.util.Date;

import org.apache.commons.lang.time.DateUtils;

import org.apache.commons.lang.time.DateFormatUtils;

public class Test {

public static void main(String args[]) {


String date2="20200405";//输入参数

try {

Date date3 = DateUtils.parseDate(date2, new String[] { "yyyyMMdd" });
Calendar calendar = Calendar.getInstance();
calendar.setTime(date3);

int dayOfWeek = calendar.get(Calendar.DAY_OF_WEEK);

if(dayOfWeek>Calendar.MONDAY){
Date date = DateUtils.addDays(calendar.getTime(), Calendar.MONDAY-dayOfWeek);
calendar.setTime(date);
}else if (dayOfWeek==Calendar.SUNDAY) {
Date date = DateUtils.addDays(calendar.getTime(), -6);
calendar.setTime(date);
}
calendar.set(Calendar.HOUR_OF_DAY, 0);
calendar.set(Calendar.MINUTE, 0);
calendar.set(Calendar.SECOND, 0);

System.out.println(DateFormatUtils.format(calendar, "yyyyMMdd"));//周一

System.out.println(DateFormatUtils.format(
DateUtils.addDays(DateUtils.parseDate(DateFormatUtils.format(calendar, "yyyyMMdd"), new String[] { "yyyyMMdd" }),6)
,"yyyyMMdd"))
;//周日


} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}

}