Java程序打印月份的不同格式
在本文中,我们将使用各种方法来使用Java编程语言的不同库格式化月份。显示月份的方法有很多种。有时月份以数字表示,有时月份以长格式表示,或者以短格式表示。
使用 java.time.Month
在这种方法中,通过指定从数字 1 开始的月份编号来打印月份。例如 -> Month.of(1) 将给出 JANUARY。
示例
在这个 Java 程序中,我们正在打印所有 12 个月名称。
import java.time.Month; public class ShowMonth { public static void main(String[] args){ Month mon; for (int mn=1; mn<=12; mn++){ // The first month starts with number 1 mon = Month.of(mn); System.out.println(mon); } } }
上述代码的输出如下所示:
JANUARY FEBRUARY MARCH APRIL MAY JUNE JULY AUGUST SEPTEMBER OCTOBER NOVEMBER DECEMBER
使用 java.util.Date 和 Arrays
在这种方法中,使用字符串数组存储月份的缩写形式,例如 Jan、Feb 等。然后,我们使用substring()方法来识别日期中的月份部分并以指定的格式打印它。
示例
以下是说明上述方法的 Java 程序。
import java.util.Date; public class ShowMonth11{ public static void main(String[] args) { // Months are stored as arrays String[] st_arr={"Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep","Oct","Nov","Dec"}; String[] seq_arr={"First", "Second", "Third", "Fourth", "Fifth", "Sixth", "Seventh", "Eighth", "Ninth","Tenth","Eleventh","Twelfth"}; // Fetch the current date Date dt = new Date(); String dtstr= dt.toString(); // printing the months for (int mn=0; mn<12; mn++){ System.out.println("The Number " + seq_arr[mn]+ " month in the year is : " +st_arr[mn]); } //selecting the month part from the date String substr2 = dtstr.substring(4,7); System.out.println("\nThe Time now is " + dt); System.out.println("\nThe current month is " + substr2); } }
运行后,将显示以下输出:
The Number First month in the year is : Jan The Number Second month in the year is : Feb The Number Third month in the year is : Mar The Number Fourth month in the year is : Apr The Number Fifth month in the year is : May The Number Sixth month in the year is : Jun The Number Seventh month in the year is : Jul The Number Eighth month in the year is : Aug The Number Ninth month in the year is : Sep The Number Tenth month in the year is : Oct The Number Eleventh month in the year is : Nov The Number Twelfth month in the year is : Dec The Time now is Fri Feb 24 13:19:06 IST 2023 The current month is Feb
使用 String 及其方法
在这种方法中,日期作为字符串输入。然后,使用substring() 方法识别并打印月份部分。月份甚至可以以数字形式显示。
示例
让我们看看实际演示:
public class ShowMonth22{ public static void main(String[] args) { String dtstr= "02-24-2023"; String dtstr1= "24-02-2023"; //getting the month part of the date String substr2 = dtstr.substring(0,2); System.out.println("\nThe date is " + dtstr); System.out.println("\nThe current month is " + substr2); //getting the month part of the date String substr3 = dtstr1.substring(3,5); System.out.println("\nThe date is " + dtstr1); System.out.println("\nThe current month is " + substr3); } }
执行此代码时,将产生以下结果:
The date is 02-24-2023 The current month is 02 The date is 24-02-2023 The current month is 02
使用 java.text.SimpleDateFormat
在这种方法中,可以将不同的格式指定为显示日期的模式。日期中的月份格式以 MMM 格式(例如 Feb)或 MMMM 格式(例如 February)打印。它还可以用于以不同的语言环境格式和语言显示月份名称。例如,在西班牙语中,February 打印为 febrero。
示例
以下是上述方法的代码:
import java.text.SimpleDateFormat; import java.util.Date; import java.util.Locale; public class ShowMonth33{ public static void main(String[] args) { Date dtt = new Date(); // MMM means date specification such as Feb, Mar etc SimpleDateFormat formatted_mmm; // MMMM means date specification such as February, March etc SimpleDateFormat formatted_mmmm; SimpleDateFormat formatted_datestyle; SimpleDateFormat formatted_datestyle1; formatted_mmm = new SimpleDateFormat("MMM"); System.out.println(formatted_mmm.format(dtt)); formatted_mmmm = new SimpleDateFormat("MMMM"); System.out.println(formatted_mmmm.format(dtt)); //Specifying the pattern of showing date time formatted_datestyle = new SimpleDateFormat("EEEE dd MMMM yyyy kk:mm:ss"); System.out.println(formatted_datestyle.format(dtt)); //Specifying the pattern of showing date time formatted_datestyle1 = new SimpleDateFormat("dd MMM yyyy kk:mm:ss"); System.out.println(formatted_datestyle1.format(dtt)); //setting for the Spanish language Locale spanishDT = new Locale("es","ES"); System.out.println("Now using Spanish: "); System.out.printf(spanishDT, "month: %tB\n", dtt); //setting for the French language SimpleDateFormat dt_fr = new SimpleDateFormat("dd MMM yyyy kk:mm:ss", new Locale("fr")); System.out.println("Now using French: "); System.out.println(dt_fr.format(dtt)); } }
以下是上述代码的输出:
Feb February Friday 24 February 2023 19:48:31 24 Feb 2023 19:48:31 Now using Spanish: month: febrero Now using French: 24 févr. 2023 19:48:31
使用 java.util.Calendar
在这种方法中,使用 Calender 对象,并使用 Calendar.MONTH 查找月份。这里索引从 0 开始,因此将 1 添加到 Calendar.MONTH 以在日期中打印正确的月份。
示例
以下 Java 程序演示了如何使用 Calendar 类打印月份。
import java.util.Calendar; public class ShowMonth44{ public static void main(String[] args) { //using Calendar instance Calendar cal = Calendar.getInstance(); //getting Time from cal System.out.println("The Current Date is: " + cal.getTime()); // Calendar Months start with 0 index therefore 1 is added for the correct result System.out.println("Current Calendar Month is : " + (cal.get(Calendar.MONTH) +1 ) ); } }
上述代码的输出为:
The Current Date is: Fri Feb 24 19:12:06 IST 2023 Current Calendar Month is: 2
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