java中LocalDateTime，LocalDate，ZonedDateTime，Date 和String的互相转换

向右看齐 2023-03-04 11:21 4阅读 0赞

最近项目使用mysql数据库进行开发，经常遇到需要日期类型和String进行转换，以下整理了一下各个日期类型和String类型转换的方法，记录一下

package com.mwclg.soa.basic;
    
    import java.text.ParseException;
    import java.text.SimpleDateFormat;
    import java.time.LocalDate;
    import java.time.LocalDateTime;
    import java.time.ZoneId;
    import java.time.ZonedDateTime;
    import java.time.format.DateTimeFormatter;
    import java.util.Date;
    
    public class Testa {
        public static void main(String[] args) throws ParseException {
            //常用的
            DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss").withZone(ZoneId.systemDefault());
            ZonedDateTime fromTime = ZonedDateTime.parse("2020-09-18 17:11:25", formatter);
    
            //ZonedDateTime 转string
            System.out.println(fromTime.format(formatter));
    
            //string转ZonedDateTime
            System.out.println(fromTime);
    
            //LocalDate转String
            LocalDate date = LocalDate.now();
            DateTimeFormatter fmt = DateTimeFormatter.ofPattern("yyyy-MM-dd");
            String dateStr = date.format(fmt);
            System.out.println("LocalDate转String:"+dateStr);
    
            //localDateTime转String
            LocalDateTime dateTime = LocalDateTime.now();
            //使用pattern来转换
            //12小时制与24小时制输出由hh的大小写决定
            DateTimeFormatter fmt12 = DateTimeFormatter.ofPattern("yyyy-MM-dd hh:mm:ss:SSS");
            String dateStr12 = dateTime.format(fmt12);
            System.out.println("LocalDateTime转String[pattern](12小时制):"+dateStr12);
    
            DateTimeFormatter fmt24 = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss:SSS");
            String dateStr24 = dateTime.format(fmt24);
            System.out.println("LocalDateTime转String[pattern](24小时制):"+dateStr24);
    
    
            //string转LocalDate 和LocalDateTime
            String str = "2017-11-21 14:41:06:612";
            DateTimeFormatter fmts = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss:SSS");
            LocalDate dates = LocalDate.parse(str, fmts);
            LocalDateTime time = LocalDateTime.parse(str, fmts);
            System.out.println("date:"+dates);
            System.out.println("time:"+time);
    
    
            //String 转Date
            SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss:SSS");
            Date dated = simpleDateFormat.parse("2019-10-31 15:24:32:222");
            System.out.println("String 转Date："+dated);
    
            //Date 转String
            String dateStrs = simpleDateFormat.format(dated);
            System.out.println("Date 转String："+dateStrs);
    
        }
    }