1. 以前日期時間類的問題

2. JDK8獲取時間物件

LocalDate(年月日)
LocatTime(時分秒)
LocatDateTime(年月日時分秒)
    
public static LocalDateTime now() : 當前時間的日期時間物件
public static LocalDateTime of(int year,
                               int month,
                               int dayOfMonth,
                               int hour,
                               int minute,
                               int second)
 

• 程式碼

        LocalDate localDate = LocalDate.now();
        LocalTime localTime = LocalTime.now();
        LocalDateTime localDateTime = LocalDateTime.now();

        System.out.println(localDate);
        System.out.println(localTime);
        System.out.println(localDateTime);

        LocalDateTime time = LocalDateTime.of(2008, 8, 8, 20, 0, 0);
        System.out.println(time);
 

3. JDK8獲取時間中的每一個值

		// 獲取當前時間的LocalDateTime
        LocalDateTime now = LocalDateTime.now();

        // 獲取年月日時分秒
        int year = now.getYear();
        int month = now.getMonthValue();
        int dayOfMonth = now.getDayOfMonth();
        int hour = now.getHour();
        int minute = now.getMinute();
        int second = now.getSecond();

        System.out.println(year + "-" + month + "-" + dayOfMonth + "-" + hour + "-" + minute + "-" + second);
 

4. JDK8對時間屬性的加減和修改

public LocalDateTime withYear(int year) : 修改年
public LocalDateTime plusYears(long years) : 增加年
public LocalDateTime minusYears(long years) : 減少年
    
// 這類方法的返回值是LocalDateTime
// 在方法的內部修改屬性值, 將修改之後的結果(LocalDateTime型別), 返回回來

5. JDK8格式化和解析

DateTimeFormatter 的獲取方式: 
public static DateTimeFormatter ofPattern(String pattern) 
    : pattern(模版)-> yyyy-MM-dd HH:mm:ss

public String format(DateTimeFormatter formatter) : 將LocatDateTime轉換成String (格式化)
        
        
public static LocalDateTime parse(CharSequence text,//CharSequence:String它爹,當成String
                                  DateTimeFormatter formatter)
        
        將字串, 轉換成LocalDateTime

6. JDK8時間間隔

• Duration

public static Duration between(Temporal startInclusive, // LocalDateTime型別
                               Temporal endExclusive)   // LocalDateTime型別
    
    
Duration:
	public long getSeconds() : 獲取相差的秒數
    public  int getNano()   : 獲取相差的納秒

• Period

public static Period between(LocalDate startDateInclusive,
                             LocalDate endDateExclusive)
    
Period:
public int getYears()
public int getMonths()
public int getDays()