java 中得到上个月的第一天和最后一天

public static String lastMonFirstDay(){

Calendar cal = Calendar.getInstance();

int year = cal.get(Calendar.YEAR);

int month = cal.get(Calendar.MONTH) + 1;

cal.set(Calendar.DAY_OF_MONTH, 1);

cal.add(Calendar.DAY_OF_MONTH, -1);

int day = cal.get(Calendar.DAY_OF_MONTH);

String months = "";

String days = "";

if (month > 1) {

month--;

} else {

year--;

month = 12;

}

if (!(String.valueOf(month).length() > 1)) {

months = "0" + month;

} else {

months = String.valueOf(month);

}

if (!(String.valueOf(day).length() > 1)) {

days = "0" + day;

} else {

days = String.valueOf(day);

}

String firstDay = "" + year + "-" + months + "-01";

String[] lastMonth = new String[2];

lastMonth[0] = firstDay;

return firstDay;

}

public static String lastMonLastDay(){

Calendar cal = Calendar.getInstance();

int year = cal.get(Calendar.YEAR);

int month = cal.get(Calendar.MONTH) + 1;

cal.set(Calendar.DAY_OF_MONTH, 1);

cal.add(Calendar.DAY_OF_MONTH, -1);

int day = cal.get(Calendar.DAY_OF_MONTH);

String months = "";

String days = "";

if (month > 1) {

month--;

} else {

year--;

month = 12;

}

if (!(String.valueOf(month).length() > 1)) {

months = "0" + month;

} else {

months = String.valueOf(month);

}

if (!(String.valueOf(day).length() > 1)) {

days = "0" + day;

} else {

days = String.valueOf(day);

}

String lastDay = "" + year + "-" + months + "-" + days;

String[] lastMonth = new String[2];

lastMonth[1] = lastDay;

return lastDay;