java实现String类型和Date类型相互转换

//自定义需要输出的String格式
SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMddHHmmss");
//输出“20230317104202”
String nowDate = sdf.format(new Date());
SimpleDateFormat sdf2 = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
//输出“2023-03-17 10:46:07”
String nowDate2 = sdf2.format(new Date());

void test() {
        SimpleDateFormat df=new SimpleDateFormat("yyyy-MM-dd");
        try {
            Date date =df.parse("2016-2-18");
            //Thu Feb 18 00:00:00 CST 2016
            System.out.println(date);
        } catch (ParseException e) {
            e.printStackTrace();
        }
    }

   void test2() {
        DateFormat format2 = new SimpleDateFormat("yyyy年MM月dd日 HH时mm分ss秒");
        // String转Date
        String str = "2016-02-18 00:00:00";
        try {
            Date date2 = format2.parse(str);
            System.out.println(date2);
        } catch (ParseException e) {
            e.printStackTrace();
        }
    }

void test3() {
        DateFormat format2 = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        // String转Date
        String str = "2016-02-18 00:00:00";
        try {
            Date date2 = format2.parse(str);
            //Thu Feb 18 00:00:00 CST 2016
            System.out.println(date2);
        } catch (ParseException e) {
            e.printStackTrace();
        }
    }

void test4() {
        Date currentTime = new Date();
        SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd");
        String dateString = formatter.format(currentTime);
        Date date = java.sql.Date.valueOf(dateString);
        //2023-03-17
        System.out.println(date);
    }

void test5() {
        String dateString = "2023-03-17";
        Date date1 = java.sql.Date.valueOf(dateString);
        //2023-03-17
        System.out.println(date1);
    }

void test6() {
        String dateString = "2023-3-7";
        Date date1 = java.sql.Date.valueOf(dateString);;
        System.out.println(date1);
    }