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);

    }

}