字符串(日期)到整数(日)+整数(月)+整数(年)到LocalDate

import java.time.LocalDate;
import java.time.format.DateTimeFormatter;
import java.util.Calendar;
import java.util.Date;

public class StringToDateToIntegerToLocalDate {
    public static void main(String[] args) {
        String dateString = "2022-10-31";
        
        // 解析字符串日期
        Date date = parseDateString(dateString);
        
        // 提取整数表示的日、月、年
        int day = extractDay(date);
        int month = extractMonth(date);
        int year = extractYear(date);
        
        // 创建LocalDate对象
        LocalDate localDate = createLocalDate(day, month, year);
        
        System.out.println("字符串日期: " + dateString);
        System.out.println("转换后的LocalDate对象: " + localDate);
    }
    
    // 解析字符串日期
    private static Date parseDateString(String dateString) {
        try {
            SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
            return sdf.parse(dateString);
        } catch (ParseException e) {
            e.printStackTrace();
        }
        return null;
    }
    
    // 提取整数表示的日
    private static int extractDay(Date date) {
        Calendar calendar = Calendar.getInstance();
        calendar.setTime(date);
        return calendar.get(Calendar.DAY_OF_MONTH);
    }
    
    // 提取整数表示的月
    private static int extractMonth(Date date) {
        Calendar calendar = Calendar.getInstance();
        calendar.setTime(date);
        return calendar.get(Calendar.MONTH) + 1; // 月份从0开始，需要+1
    }
    
    // 提取整数表示的年
    private static int extractYear(Date date) {
        Calendar calendar = Calendar.getInstance();
        calendar.setTime(date);
        return calendar.get(Calendar.YEAR);
    }
    
    // 创建LocalDate对象
    private static LocalDate createLocalDate(int day, int month, int year) {
        return LocalDate.of(year, month, day);
    }
}