Java 常用类库 之 Calandar 日期处理类

http://www.verejava.com/?id=16993050424091

/**
    知识点：Calandar 日期处理类
*/
import java.util.Calendar;
import java.util.GregorianCalendar;

public class TestCalendar {
    
    public static void main(String[] args) {
        //实例化 Calandar 对象
        Calendar c = new GregorianCalendar();
        //输出年，月，日，时，分，秒
        System.out.println(c.get(Calendar.YEAR));
        //注意：Gregorian日历1月从 0 开始所以要加1
        System.out.println(c.get(Calendar.MONTH) + 1);
        System.out.println(c.get(Calendar.DATE));
        System.out.println(c.get(Calendar.HOUR));
        System.out.println(c.get(Calendar.MINUTE));
        System.out.println(c.get(Calendar.SECOND));
        System.out.println(c.get(Calendar.MILLISECOND));

        //获得当前日期
        System.out.println(DateTime.getDate());
        //获得当前日期时间
        System.out.println(DateTime.getDateTime());
        //获得当前日期时间戳
        System.out.println(DateTime.getTimeStamp());
    }
}

/**
    日期类的封装
        1. 取得当前日期
        2. 取得当前日期时间
        3. 取得当前时间戳
*/
class DateTime {
    
    //取得当前日期
    public static String getDate() {
        Calendar c = new GregorianCalendar();
        StringBuffer buffer = new StringBuffer();
        buffer.append(c.get(Calendar.YEAR)).append("-");
        buffer.append(addZero(c.get(Calendar.MONTH) + 1)).append("-");
        buffer.append(addZero(c.get(Calendar.DATE)));
        return buffer.toString();
    }

    //取得当前日期时间
    public static String getDateTime() {
        Calendar c = new GregorianCalendar();
        StringBuffer buffer = new StringBuffer();
        buffer.append(c.get(Calendar.YEAR)).append("-");
        buffer.append(addZero(c.get(Calendar.MONTH) + 1)).append("-");
        buffer.append(addZero(c.get(Calendar.DATE))).append(" ");
        buffer.append(addZero(c.get(Calendar.HOUR))).append(":");
        buffer.append(addZero(c.get(Calendar.MINUTE))).append(":");
        buffer.append(addZero(c.get(Calendar.SECOND)));
        return buffer.toString();
    }

    //获取当前时间戳
    public static long getTimeStamp() {
        Calendar c = new GregorianCalendar();
        return c.getTime().getTime();
    }

    //如果月，日，时，分，秒小于 10 在前面添加0
    public static String addZero(int value) {
        String str = Integer.toString(value);
        if (str.length() < 2)
            return 0 + str;
        return str;
    }

}

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