常用类12/DateTimeFormatter的使用

àì夳堔傛蜴生んèń 2023-10-04 16:46 1阅读 0赞

### DateTimeFormatter的使用 ###

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80ODA2MzY2MA_size_16_color_FFFFFF_t_70]

不需要全部记住，了解，记住类以及作用即可

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**DateTimeFormatter:格式化或解析日期、时 间  
类似于SimpleDateFormat**

> **方式一**：预定义的标准格式如:ISo\_LOCAL\_DATE\_TIME;ISo\_LOCAL\_DATE;ISO\_LOCAL\_TIME  
> **方式二**：本地化相关的格式。如: ofLocalizedDateTime(FormatStyle.LONG)  
> **方式三**：自定义的格式。如: ofPattern(“yyyy-MM-dd hh:mm:ss E”)

> DateTimeFormatter的使用：

package com.cyl.Date;
    
    import com.sun.scenario.effect.impl.sw.sse.SSEBlend_SRC_OUTPeer;
    import org.junit.Test;
    
    import java.time.LocalDate;
    import java.time.LocalDateTime;
    import java.time.format.DateTimeFormatter;
    import java.time.format.FormatStyle;
    import java.time.temporal.TemporalAccessor;
    
    public class JDK8DateTimeTest {
        
        //LocalDate,LocalTime,LocalDateTime 的使用
        @Test
        public void test3(){
        
            DateTimeFormatter formatter = DateTimeFormatter.ISO_LOCAL_DATE_TIME;
            //格式化：日期-->字符串
            LocalDateTime localDateTime = LocalDateTime.now();//当前时间
            String str1 = formatter.format(localDateTime);//格式化为字符串
            System.out.println(localDateTime);//2021-08-11T15:31:18.742
            System.out.println(str1);//2021-08-11T15:31:18.742
    
            //解析：字符串-->日期
            TemporalAccessor parse = formatter.parse("2021-08-11T14:20:46.505");
            System.out.println(parse);//{},ISO resolved to 2021-08-11T14:20:46.505
    
            //方式二：本地化相关的格式。如: ofLocalizedDateTime()
            //FormatStyle.LONG/FormatSytle.MEDIUM/ FormatStyle.SHORT:适用于localDateTime
            DateTimeFormatter formatter1 = DateTimeFormatter.ofLocalizedDateTime(FormatStyle.SHORT);
            //格式化
            String str2 = formatter1.format(localDateTime);
            System.out.println(str2);//21-8-11 下午3:31
    
            //本地化相关的格式。如: ofLocalizedDate()
            //FormatStyLe.FULL / FormatStyle.LONG /FormatStyLe.MEDIUN / FormatStyle.SHORT:适用于LocalDate
            DateTimeFormatter formatter2 = DateTimeFormatter.ofLocalizedDate(FormatStyle.MEDIUM);
            //格式化
            String str3 = formatter2.format(LocalDate.now());
            System.out.println(str3);//2021-8-11
    
            //重点
            //方式三：自定义的格式。如: ofPattern("yyyy-MM-dd hh:mm:ss E")
            DateTimeFormatter formatter3 = DateTimeFormatter.ofPattern("yyyy-MM-dd hh:mm:ss");
            //格式化
            String str4 = formatter3.format(LocalDateTime.now());
            System.out.println(str4);//2021-08-11 03:31:18
    
            //解析
            TemporalAccessor accessor = formatter3.parse("2021-08-11 03:29:19");
            System.out.println(accessor);
    
        }
    }

> 结果  
> ![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80ODA2MzY2MA_size_16_color_FFFFFF_t_70 1]

> 参考时间  
> ![在这里插入图片描述][29a699f0c9434b84b12ad9d5389fcab1.png]

--------------------

#### 其他API参考与转换 ####

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80ODA2MzY2MA_size_16_color_FFFFFF_t_70 2]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80ODA2MzY2MA_size_16_color_FFFFFF_t_70 3]

DateTimeFormatter的使用：[给我整麻了][Link 1]

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[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80ODA2MzY2MA_size_16_color_FFFFFF_t_70 1]: https://img-blog.csdnimg.cn/f97f37ef7db3413a91eb793dd0cbd1cb.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80ODA2MzY2MA==,size_16,color_FFFFFF,t_70
[29a699f0c9434b84b12ad9d5389fcab1.png]: https://img-blog.csdnimg.cn/29a699f0c9434b84b12ad9d5389fcab1.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80ODA2MzY2MA_size_16_color_FFFFFF_t_70 2]: https://img-blog.csdnimg.cn/bb6583f1a18542b49b91dda296f84a4a.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80ODA2MzY2MA==,size_16,color_FFFFFF,t_70
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[Link 1]: https://www.bilibili.com/video/BV1Kb411W75N?p=487