String、Date、Calendar之间的转换

1.String、Date、Calendar之间的转换

　　要用到格式化类SimpleDateFormat

 package com.rong.se;

 import java.text.ParseException;

 import java.text.SimpleDateFormat;

 import java.util.Calendar;

 import java.util.Date;

 public class StringDate {

     public static void main(String[] args) {

         // 格式化对象

         SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

         // SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");

         // /////////////////////////////////////////////////////

         // SimpleDateFormat sdf=new SimpleDateFormat();

         // sdf.applyPattern("yyyy-MM-dd hh:mm:ss");

         try {

             // String类型转换为Date类型

             String string = "2017-11-11 20:20:20";

             Date date = sdf.parse(string);

             System.out.println(date);

         } catch (ParseException e) {

             e.printStackTrace();

         }

         // Date类型转换为String类型

         Date date = new Date();

         String format = sdf.format(date);

         System.out.println(format);

         // Calendar类型转换为Date类型

         Calendar calendar = Calendar.getInstance();

         Date cDate = calendar.getTime();

         System.out.println(cDate);

         // Date类型转换为Calendar类型

         try {

             String string = "1995-09-24 13:14:03";

             Date parse = sdf.parse(string);

             // ///////////////////////////////////

             calendar.setTime(parse);

             // 获取年份

             System.out.println(calendar.get(Calendar.YEAR));

         } catch (ParseException e) {

             e.printStackTrace();

         }

         // String类型转换为Calendar类型

         try {

             String str = "2002-01-01 18:30:00";

             Date parse = sdf.parse(str);

             Calendar instance = Calendar.getInstance();

             instance.setTime(parse);

             System.out.println(instance.get(Calendar.YEAR));

         } catch (ParseException e) {

             e.printStackTrace();

         }

         // Calendar类型转换为String类型

         Calendar instance = Calendar.getInstance();

         Date time = instance.getTime();

         String string = sdf.format(time);

         System.out.println(string);

     }

 }