java 获取当前月份上一个月1号0点和当前月份下一个月月底24点 返回Date()

可以使用以下代码实现：

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

public class Main {
    public static void main(String[] args) {
        Calendar calendar = Calendar.getInstance();
        calendar.add(Calendar.MONTH, -1);
        calendar.set(Calendar.DAY_OF_MONTH, 1);
        calendar.set(Calendar.HOUR_OF_DAY, );
        calendar.set(Calendar.MINUTE, );
        calendar.set(Calendar.SECOND, );
        Date lastMonthFirstDay = calendar.getTime();

        calendar = Calendar.getInstance();
        calendar.add(Calendar.MONTH, 1);
        calendar.set(Calendar.DAY_OF_MONTH, 1);
        calendar.set(Calendar.HOUR_OF_DAY, );
        calendar.set(Calendar.MINUTE, );
        calendar.set(Calendar.SECOND, );
        calendar.add(Calendar.SECOND, -1);
        Date nextMonthLastDay = calendar.getTime();

        System.out.println("上个月1号点：" + lastMonthFirstDay);
        System.out.println("下个月月底24点：" + nextMonthLastDay);
    }
}