LocalDateTime、LocalDate是JDK1.8提供的新的时间操作接口，而Date是JDK1.0提供的时间操作接口，LocalDateTime/LocalDate提供许多便捷的时间操作函数，使用起来相当方便，在实际的编程中经常会用到这几个类，有时候难免会存在相互转换的情况，本文将使用代码讲解具体的转换过程。

一、LocalDateTime转Date

package com.test;
import java.time.ZoneId;
import java.time.LocalDateTime;
import java.util.Date;
import java.util.Calendar;

public class Test{

public static void main(String[] args)
    // LocalDateTime 转 Date
    LocalDateTime localDateTime = LocalDateTime.now();
    System.out.println("local:"+localDateTime.getYear());
    ZoneId zoneId = ZoneId.systemDefault();
    Date date = Date.from(localDateTime.atZone(zoneId).toInstant());
    Calendar calendar = Calendar.getInstance();
    calendar.setTime(date);
    System.out.println("date:"+calendar.get(Calendar.YEAR));
}

二、LocalDate转Date

package com.test;
import java.time.ZoneId;
import java.time.LocalDate;
import java.util.Date;
import java.util.Calendar;

public class Test{

public static void main(String[] args)
    // LocalDate 转 Date
    LocalDate localDate = LocalDate.now();
    System.out.println("local:"+localDate.getYear());
    ZoneId zoneId = ZoneId.systemDefault();
    Date date = Date.from(localDate.atStartOfDay().atZone(zoneId).toInstant());
    Calendar calendar = Calendar.getInstance();
    calendar.setTime(date);
    System.out.println("date:"+calendar.get(Calendar.YEAR));
}

三、Date转LocalDate、LocalDateTime

package com.test;
import java.time.ZoneId;
import java.time.LocalDate;
import java.time.LocalDateTime;
import java.util.Date;
import java.util.Calendar;

public class Test{

public static void main(String[] args){
    Date date = new Date();
    // Date 转 LocalDate
    Calendar calendar = Calendar.getInstance();
    calendar.setTime(date);
    LocalDate localDate = LocalDate.of(calendar.get(Calendar.YEAR),calendar.get(Calendar.MONTH),calendar.get(DAY_OF_MONTH));
    // Date 转 LocalDateTime 
    LocalDateTime localDateTime = LocalDateTime.ofInstant(date.toInstant(),ZoneId.systemDefault());
    }
}