【點滴】Java Calendar 類的使用__Java

每次用都要翻翻API，加強記憶

import java.text.DateFormat;import java.text.SimpleDateFormat;import java.util.Calendar;import java.util.Date;import org.junit.Test;public class TestCalendar {@Testpublic void testCalendar() {Calendar calendar = Calendar.getInstance();System.out.println(calendarToString(calendar));}public String calendarToString(Calendar calendar) {String str = calendar.get(Calendar.YEAR)+"/"+(calendar.get(Calendar.MONTH)+1)+"/"+calendar.get(Calendar.DATE);return str;}/** * 特定格式轉換為Date對象 * @throws Exception */@Testpublic void testDate() throws Exception {DateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss:SSS");Date date = df.parse("2015-6-6 19:21:30:456");System.out.println(date);} /** * 將Date轉換為特定格式的字串 */@Testpublic void testDateToString() {Date date = new Date();System.out.println(dateToString(date));}public String dateToString(Date date) {//2015-06-06 19:33:20:376//return new SimpleDateFormat("yyyy-MM-dd HH:mm:ss:SSS").format(date);//2015-6-6return DateFormat.getDateInstance(DateFormat.DEFAULT).format(date);//2015年6月6日 星期六//return DateFormat.getDateInstance(DateFormat.FULL).format(date);//2015-6-6//return DateFormat.getDateInstance(DateFormat.MEDIUM).format(date);//15-6-6//return DateFormat.getDateInstance(DateFormat.SHORT).format(date);}@Testpublic void getSpecialDay() {Calendar calendar = Calendar.getInstance();//month從0開始，5即為6月calendar.set(2015, 5, 6);System.out.println(calendarToString(calendar));//擷取到前10天的日期calendar.set(calendar.get(Calendar.YEAR), calendar.get(Calendar.MONTH), calendar.get(Calendar.DATE)-10);System.out.println(calendarToString(calendar));//擷取到後10天的日期calendar.set(2015, 5, 6);calendar.set(Calendar.DATE,calendar.get(Calendar.DATE)+10);System.out.println(calendarToString(calendar));}}