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Java LocalDate日期格式化使用示例

转载 作者:知者 更新时间:2024-03-12 08:01:10 26 4
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我们可以使用 LocalDateDateTimeFormatterformat() 方法将 LocalDate 格式化为字符串。 Java 8 中引入的 LocalDate 表示格式为 yyyy-MM-dd 的日期,例如 2019-05-08。它不存储时间或时区。我们可以使用 DateTimeFormatterLocalDate 格式化为所需的格式。要格式化 LocalDate,我们可以使用以下方法。
LocalDate.format():使用指定的格式化程序格式化此日期。输出将是字符串。

LocalDate localDate = LocalDate.parse("2019-05-08");
String date = localDate.format(DateTimeFormatter.ofPattern("MMM dd, yyyy"));
System.out.println(date); //May 08, 2019

DateTimeFormatter.format():使用此格式化程序格式化日期时间对象。输出将是字符串。

LocalDate localDate = LocalDate.parse("2019-05-08");
DateTimeFormatter dtf = DateTimeFormatter.ofPattern("MMM dd, yyyy");
String date = dtf.format(localDate);
System.out.println(date); //May 08, 2019

使用 LocalDate.format() 格式化 LocalDate

Example-1:这里我们将使用 ofPattern 方法实例化 DateTimeFormatter,然后我们将此格式化程序实例传递给 LocalDateformat() 方法。
LDFormatDemoOne.java

package com.concretepage;
import java.time.LocalDate;
import java.time.format.DateTimeFormatter;
public class LDFormatDemoOne {
  public static void main(String[] args) {
	LocalDate localDate = LocalDate.parse("2019-05-08");
	
	String date = localDate.format(DateTimeFormatter.ofPattern("MMM dd, yyyy"));
	System.out.println(date); //May 08, 2019
	
	date = localDate.format(DateTimeFormatter.ofPattern("yyyy.MM.dd"));
	System.out.println(date); //2019.05.08
	
	date = localDate.format(DateTimeFormatter.ofPattern("EEE, MMM d, ''yy"));
	System.out.println(date); //Wed, May 8, '19
	
	date = localDate.format(DateTimeFormatter.ofPattern("yyyy-MMM-dd(E)"));
	System.out.println(date); //2019-May-08(Wed)		
	
	date = localDate.format(DateTimeFormatter.ofPattern("yyyyy.MMMMM.dd GGG"));
	System.out.println(date); //02019.M.08 AD
	
	date = localDate.format(DateTimeFormatter.ofPattern("EEE, d MMM yyyy"));
	System.out.println(date); //Wed, 8 May 2019
	
	date = localDate.format(DateTimeFormatter.ofPattern("MMM, yyyy"));
	System.out.println(date); //May, 2019
  }
}

输出

May 08, 2019
2019.05.08
Wed, May 8, '19
2019-May-08(Wed)
02019.M.08 AD
Wed, 8 May 2019
May, 2019

Example-2:这里我们将使用 ofLocalizedDate 方法实例化 DateTimeFormatter,然后我们将此格式化程序实例传递给 LocalDateformat() 方法。
LDFormatDemoTwo.java

package com.concretepage;
import java.time.LocalDate;
import java.time.format.DateTimeFormatter;
import java.time.format.FormatStyle;
import java.time.format.ResolverStyle;
import java.util.Locale;
public class LDFormatDemoTwo {
  public static void main(String[] args) {
	LocalDate localDate = LocalDate.parse("2019-05-08");
	
	String date = localDate.format(DateTimeFormatter.ofLocalizedDate(FormatStyle.FULL));
	System.out.println(date); // Wednesday, May 8, 2019
	
	date = localDate.format(DateTimeFormatter.ofLocalizedDate(FormatStyle.FULL).localizedBy(Locale.UK));
	System.out.println(date); // Wednesday, 8 May 2019
	
	date = localDate.format(DateTimeFormatter.ofLocalizedDate(FormatStyle.FULL).withResolverStyle(ResolverStyle.SMART));
	System.out.println(date); // Wednesday, May 8, 2019	
	
	date = localDate.format(DateTimeFormatter.ofLocalizedDate(FormatStyle.LONG));
	System.out.println(date); // May 8, 2019
	
	date = localDate.format(DateTimeFormatter.ofLocalizedDate(FormatStyle.MEDIUM));
	System.out.println(date); // May 8, 2019

	date = localDate.format(DateTimeFormatter.ofLocalizedDate(FormatStyle.SHORT));
	System.out.println(date); // 5/8/19
  }
}

输出

Wednesday, May 8, 2019
Wednesday, 8 May 2019
Wednesday, May 8, 2019
May 8, 2019
May 8, 2019
5/8/19

Example-3:这里我们将使用其预定义格式实例化 DateTimeFormatter,然后我们将此格式化程序实例传递给 LocalDateformat() 方法。
LDFormatDemoThree.java

package com.concretepage;
import java.time.LocalDate;
import java.time.format.DateTimeFormatter;
public class LDFormatDemoThree {
  public static void main(String[] args) {
	LocalDate localDate = LocalDate.parse("2019-05-08");
	
	String date = localDate.format(DateTimeFormatter.BASIC_ISO_DATE);
	System.out.println(date); // 20190508

	date = localDate.format(DateTimeFormatter.ISO_DATE);
	System.out.println(date); // 2019-05-08
	
	date = localDate.format(DateTimeFormatter.ISO_LOCAL_DATE);
	System.out.println(date); // 2019-05-08	
	
	date = localDate.format(DateTimeFormatter.ISO_ORDINAL_DATE);
	System.out.println(date); // 2019-128	
	
	date = localDate.format(DateTimeFormatter.ISO_WEEK_DATE);
	System.out.println(date); // 2019-W19-3		
  }
}

输出

20190508
2019-05-08
2019-05-08
2019-128
2019-W19-3

使用 DateTimeFormatter.format() 格式化 LocalDate

示例 1:这里我们将使用 ofPattern 方法实例化 DateTimeFormatter,然后将 LocalDate 实例传递给 DateTimeFormatterformat() 方法。
DTFFormatDemoOne.java

package com.concretepage;
import java.time.LocalDate;
import java.time.format.DateTimeFormatter;
public class DTFFormatDemoOne {
  public static void main(String[] args) {
	LocalDate localDate = LocalDate.parse("2019-05-08");
	
	DateTimeFormatter dtf = DateTimeFormatter.ofPattern("MMM dd, yyyy");
	String date = dtf.format(localDate);
	System.out.println(date); //May 08, 2019
	
	dtf = DateTimeFormatter.ofPattern("yyyy.MM.dd");
	date = dtf.format(localDate);
	System.out.println(date); //2019.05.08
	
	dtf = DateTimeFormatter.ofPattern("EEE, MMM d, ''yy");
	date = dtf.format(localDate);
	System.out.println(date); //Wed, May 8, '19
	
	dtf = DateTimeFormatter.ofPattern("yyyy-MMM-dd(E)");
	date = dtf.format(localDate);
	System.out.println(date); //2019-May-08(Wed)		
	
	dtf = DateTimeFormatter.ofPattern("yyyyy.MMMMM.dd GGG");
	date = dtf.format(localDate);
	System.out.println(date); //02019.M.08 AD
	
	dtf = DateTimeFormatter.ofPattern("EEE, d MMM yyyy");
	date = dtf.format(localDate);
	System.out.println(date); //Wed, 8 May 2019
	
	dtf = DateTimeFormatter.ofPattern("MMM, yyyy");
	date = dtf.format(localDate);
	System.out.println(date); //May, 2019
  }
}

输出

May 08, 2019
2019.05.08
Wed, May 8, '19
2019-May-08(Wed)
02019.M.08 AD
Wed, 8 May 2019
May, 2019

示例 2:这里我们将使用 ofLocalizedDate 方法实例化 DateTimeFormatter,然后将 LocalDate 实例传递给 DateTimeFormatterformat() 方法。
DTFFormatDemoTwo.java

package com.concretepage;
import java.time.LocalDate;
import java.time.format.DateTimeFormatter;
import java.time.format.FormatStyle;
import java.time.format.ResolverStyle;
import java.util.Locale;
public class DTFFormatDemoTwo {
  public static void main(String[] args) {
	LocalDate localDate = LocalDate.parse("2019-05-08");
	
	DateTimeFormatter dtf = DateTimeFormatter.ofLocalizedDate(FormatStyle.FULL);
	String date = dtf.format(localDate);
	System.out.println(date); // Wednesday, May 8, 2019
	
	dtf = DateTimeFormatter.ofLocalizedDate(FormatStyle.FULL).localizedBy(Locale.UK);
	date = dtf.format(localDate);
	System.out.println(date); // Wednesday, 8 May 2019
	
	dtf = DateTimeFormatter.ofLocalizedDate(FormatStyle.FULL).withResolverStyle(ResolverStyle.SMART);
	date = dtf.format(localDate);
	System.out.println(date); // Wednesday, May 8, 2019	
	
	dtf = DateTimeFormatter.ofLocalizedDate(FormatStyle.LONG);
	date = dtf.format(localDate);
	System.out.println(date); // May 8, 2019
	
	dtf = DateTimeFormatter.ofLocalizedDate(FormatStyle.MEDIUM);
	date = dtf.format(localDate);
	System.out.println(date); // May 8, 2019

	dtf = DateTimeFormatter.ofLocalizedDate(FormatStyle.SHORT);
	date = dtf.format(localDate);
	System.out.println(date); // 5/8/19
  }
}

输出

Wednesday, May 8, 2019
Wednesday, 8 May 2019
Wednesday, May 8, 2019
May 8, 2019
May 8, 2019
5/8/19

示例 3:这里我们将使用其预定义格式实例化 DateTimeFormatter,然后将 LocalDate 实例传递给 DateTimeFormatterformat() 方法。
DTFFormatDemoThree.java

package com.concretepage;
import java.time.LocalDate;
import java.time.format.DateTimeFormatter;
public class DTFFormatDemoThree {
  public static void main(String[] args) {
	LocalDate localDate = LocalDate.parse("2019-05-08");
	
	String date = DateTimeFormatter.BASIC_ISO_DATE.format(localDate);
	System.out.println(date); // 20190508

	date = DateTimeFormatter.ISO_DATE.format(localDate);
	System.out.println(date); // 2019-05-08
	
	date = DateTimeFormatter.ISO_LOCAL_DATE.format(localDate);
	System.out.println(date); // 2019-05-08	
	
	date = DateTimeFormatter.ISO_ORDINAL_DATE.format(localDate);
	System.out.println(date); // 2019-128	
	
	date = DateTimeFormatter.ISO_WEEK_DATE.format(localDate);
	System.out.println(date); // 2019-W19-3		
  }
}

输出

20190508
2019-05-08
2019-05-08
2019-128
2019-W19-3

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