JAVA基础--日期处理

时间:2021-02-14 05:08:06

用SimpleDateFormat方法格式化日期格式:

package DAO;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;
import java.sql.Timestamp;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date; public class TestDate {
public static void main(String[] args) throws Exception{
Class.forName("com.mysql.jdbc.Driver").newInstance();
Connection conn = DriverManager.getConnection("jdbc:mysql://109.110.100.56/tsdr_project?user=root");
Statement stmt=conn.createStatement();
ResultSet rs = stmt.executeQuery("select distinct UpdateTime from defects_infor_daily");
while(rs.next()){
Date d = rs.getDate("UpdateTime");
Timestamp ts=rs.getTimestamp("UpdateTime");
//SimpleDateFormat sdf = new SimpleDateFormat("yyyy年MM月dd日");
SimpleDateFormat sdf = new SimpleDateFormat("yyyy.MM.dd G 'at' HH:mm:ss z");
System.out.println(sdf.format(d)); //2016.04.11 公元 at 00:00:00 CST
System.out.println(sdf.format(ts)); //2016.04.11 公元 at 07:30:35 CST
Calendar c= Calendar.getInstance();
c.setTime(d);
System.out.println(c.get(Calendar.MONTH)); //3
}
rs.close();
stmt.close();
conn.close();
}
}

  

UTC:世界时间

GMT: 格林威治时间,


java.util.Timezone

java.util.Calendar                          java.util.Date                                                                                    java.text.DateFormat

java.util.GregrorianCalendar             java.sql.Date    java.sql.Time      java.sql.Timestamp                               java.text.SimpleDateFormat


package DAO;

import java.sql.Timestamp;
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;
import java.util.TimeZone; public class TestDateAndTime {
public static void main(String[] args) throws Exception{
System.out.println(System.currentTimeMillis()); //1460360597062 Date d = new Date();
System.out.println(d); //Mon Apr 11 15:43:17 CST 2016 Calendar c = Calendar.getInstance();
System.out.println(c.get(Calendar.YEAR)); //2016 String s = "1970-12-30 08:24:37.0";
Timestamp ts = Timestamp.valueOf(s);
System.out.println(ts); //1970-12-30 08:24:37.0 Calendar cts = Calendar.getInstance();
cts.setTime(ts);
System.out.println(cts.get(Calendar.MONTH)+1); //12 Calendar cJapan = new GregorianCalendar(TimeZone.getTimeZone("Japan")); //参数是日本的时区
System.out.println(cJapan.get(Calendar.HOUR_OF_DAY)); //16 比中国晚1个小时 for(String str:TimeZone.getAvailableIDs()){
System.out.println(str); //显示所有时区, 替代Japan
} }
}