package DateDemo;

import java.text.DateFormat;

import java.text.SimpleDateFormat;

import java.time.Year;

import java.util.Calendar;

import java.util.Date;

public class DateDemo {

public static void main(String[] args) {

System.out.println("-----");

DateFormat dfm = new SimpleDateFormat("yyyy-MM-DD HH:mm:ss");

Date date = new Date();

String str = dfm.format(date);

System.out.println(str);

//Calendar日历类，add（） set（）get（）

Calendar calendar = Calendar.getInstance();

calendar.set(Calendar.YEAR,2023);

Date date1 = calendar.getTime();//获取毫秒时刻

System.out.println(date1);

calendar.add(Calendar.YEAR,2);

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

System.out.println(year);

//获取当前系统时间

long starttime = System.currentTimeMillis();

SimpleDateFormat simpleDateFormat = new SimpleDateFormat("YYYY-MM-DD HH:mm:ss");

Date date2 = new Date();

System.out.println("当前执行时间是"+ starttime);

int sum = 0;

try{

for (int i =1 ;i<100;i++){

sum += i;

}

}catch (Exception e){

System.out.println(e);

}

long endtime = System.currentTimeMillis();

System.out.println("最后执行时间"+ endtime);

System.out.println("运行时间"+ (endtime-starttime) + "毫秒");

StringBuilder stringBuilder = new StringBuilder();

stringBuilder.append("hello").append("world").append(false).append(1000);

System.out.println(stringBuilder.toString());

int num2 = Integer.parseInt("100129");

System.out.println(num2);

}

}