java String、Date、LocalDate相互转换

偏执的太偏执、 2023-09-26 11:07 39阅读 0赞

String 和 LocalDate 借助 DateTimeFormatter  
//String -> LocalDateTime  
String timeStr = "2022/6/20"  
LocalDate parse = LocalDate.parse(timeStr,  
DateTimeFormatter.ofPattern("yyyy/M/dd"));  
//LocalDateTime -> String  
LocalDateTime now = LocalDateTime.now();  
//s = 2022-06-20T18:42:35.332  
String s = now.toString();  
Date 和 LocalDate 借助 Instance  
Date date = new Date();  
//Date -> LocalDate  
LocalDate localDate = date.toInstant()  
.atZone(ZoneId.systemDefault()).toLocalDate();  
//Date -> LocalDateTime  
LocalDateTime localDateTime = date.toInstant()  
.atZone(ZoneId.systemDefault()).toLocalDateTime();  
System.out.println("localDate = " + localDate);  
System.out.println("localDateTime = " + localDateTime);  
//LocalDateTime -> Date  
Date from = Date  
.from(localDateTime.atZone(ZoneId.systemDefault()).toInstant());  
System.out.println("from = " + from);  
Date 和 String 借助 SimpleDateFormat  
String date = "2022/6/20 23:11:59";  
//String -> Date  
SimpleDateFormat dateFormat =  
new SimpleDateFormat("yyyy/MM/dd hh:mm:ss");  
Date parse = dateFormat.parse(date);  
//parse = Mon Jun 20 23:11:59 CST 2022  
System.out.println("parse = " + parse);  
  
//Date -> String  
String s = parse.toString();  
//s = Mon Jun 20 23:11:59 CST 2022  
System.out.println("s = " + s);  
测一测，下面的代码是否报错？  
如果会报错，请现将那个 parse 发到评论区。然后自己CV玩一把看看吧~~~

String timeStr = "2022/10/30";  
LocalDate parse = LocalDate.parse(timeStr,  
DateTimeFormatter.ofPattern("yyyy/MM/dd"));  
System.out.println("parse = " + parse);  
LocalDate parse2 = LocalDate.parse(timeStr,  
DateTimeFormatter.ofPattern("yyyy/M/dd"));  
System.out.println("parse2 = " + parse2);  
  
String timeStr2 = "2022/3/30";  
LocalDate parse3 = LocalDate.parse(timeStr2,  
DateTimeFormatter.ofPattern("yyyy/MM/dd"));  
System.out.println("parse3 = " + parse3);  
LocalDate parse4 = LocalDate.parse(timeStr2,  
DateTimeFormatter.ofPattern("yyyy/M/dd"));  
System.out.println("parse4 = " + parse4);  
  
String timeStr3 = "2022/03/30";  
LocalDate parse5 = LocalDate.parse(timeStr3,  
DateTimeFormatter.ofPattern("yyyy/MM/dd"));  
System.out.println("parse5 = " + parse5);  
LocalDate parse6 = LocalDate.parse(timeStr3,  
DateTimeFormatter.ofPattern("yyyy/M/dd"));  
System.out.println("parse6 = " + parse6);  
  
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原文链接：https://blog.csdn.net/a\_littleStory/article/details/125378322