java 获取当月第一天跟最后一天 获取前一个月第一天和最后一天

java 获取当月第一天和最后一天 获取前一个月第一天和最后一天

??? ??? SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd");
??? ???
??? ??? //获取前月的第一天
??? ??? Calendar?? cal_1=Calendar.getInstance();//获取当前日期
??? ??? cal_1.add(Calendar.MONTH, -1);
??? ??? cal_1.set(Calendar.DAY_OF_MONTH,1);//设置为1号,当前日期既为本月第一天
??? ??? firstDay = format.format(cal_1.getTime());
??? ??? System.out.println("-----1------firstDay:"+firstDay);
??? ??? //获取前月的最后一天
??? ??? Calendar cale = Calendar.getInstance();??
??? ??? cale.set(Calendar.DAY_OF_MONTH,0);//设置为1号,当前日期既为本月第一天
??? ??? lastDay = format.format(cale.getTime());
??? ??? System.out.println("-----2------lastDay:"+lastDay);
??? ???
??? ???
??? ??? //获取当前月第一天：
??? ??? Calendar c = Calendar.getInstance();???
??? ??? c.add(Calendar.MONTH, 0);
??? ??? c.set(Calendar.DAY_OF_MONTH,1);//设置为1号,当前日期既为本月第一天
??? ??? String first = format.format(c.getTime());
??? ??? System.out.println("===============first:"+first);
??? ???
??? ??? //获取当前月最后一天
??? ??? Calendar ca = Calendar.getInstance();???
??? ??? ca.set(Calendar.DAY_OF_MONTH, ca.getActualMaximum(Calendar.DAY_OF_MONTH));?
??? ??? String last = format.format(ca.getTime());
??? ??? System.out.println("===============last:"+last);