java获得当前日期的上个月的最后一天的日期&&每月的最大天数

// 获得当前时间所在月份的上个月的最后一天所在日期
public String getLastMonthDay(Timestamp t) {
Calendar cal = Calendar.getInstance();
Date date = t;
cal.setTime(date);
int year = 0;
int month = cal.get(Calendar.MONTH); // 上个月月份
//设置年月
if (month == 0) {
year = cal.get(Calendar.YEAR) - 1;
month = 12;
} else {
year = cal.get(Calendar.YEAR);
}
//设置天数
String temp=year + "-" + month ;
SimpleDateFormat format = new SimpleDateFormat("yyyy-MM");
Date d = null;
try {
d = format.parse(temp);
} catch (ParseException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
cal.setTime(d);
int day =cal.getActualMaximum(Calendar.DAY_OF_MONTH);
String endDay = year + "-" + month + "-" + day;
return endDay;
}

//得到某月的天数
public int getMonthDay(String source){
//String source = "2007年12月";
int count=30;
SimpleDateFormat format = new SimpleDateFormat("yyyy年MM月");
try {
Date date = format.parse(source);
Calendar calendar = new GregorianCalendar();
calendar.setTime(date);
count=calendar.getActualMaximum(Calendar.DAY_OF_MONTH);
}catch (Exception e) {
e.printStackTrace();
}
return count;
}