Java中的 SimpleDateFormat applyPattern() 方法及示例

SimpleDateFormat 类的applyPattern()方法用于将给定的已定义模式设置为日期格式。它只是将特定日期和时间转换为用户定义的特定格式，例如 dd/ MM/ yyyy HH:mm Z 或 MM/ dd/ yyyy HH:mm Z。
句法：

public void applyPattern(String pattern)

参数：该方法采用一个字符串类型的参数模式，并引用此日期格式的新日期和时间模式。
返回值：该方法返回void类型。
下面的程序说明了 SimpleDateFormat 的 applyPattern() 方法的工作：
示例 1：

Java

// Java code to illustrate
// applyPattern() method
 
import java.text.*;
import java.util.Calendar;
 
public class SimpleDateFormat_Demo {
 
    public static void main(String[] args)
        throws InterruptedException
    {
        SimpleDateFormat SDFormat
            = new SimpleDateFormat();
 
        // Initializing the calendar Object
        Calendar cal = Calendar.getInstance();
 
        // Using the below pattern
        String new_pat = "dd/ MM/ yyyy HH:mm Z";
 
        // Use of applyPattern() method
        SDFormat.applyPattern(new_pat);
 
        // Displaying Current date and time
        String curr_date
            = SDFormat.format(cal.getTime());
 
        System.out.println("The Current Date: "
                           + curr_date);
 
        // Displaying the pattern
        System.out.println("Applied Pattern: "
                           + SDFormat.toPattern());
    }
}

输出：

The Current Date: 29/ 01/ 2019 07:22 +0000
Applied Pattern: dd/ MM/ yyyy HH:mm Z

示例 2：

Java

// Java code to illustrate
// applyPattern() method
 
import java.text.*;
import java.util.Calendar;
 
public class SimpleDateFormat_Demo {
 
    public static void main(String[] args)
        throws InterruptedException
    {
        SimpleDateFormat SDFormat
            = new SimpleDateFormat();
 
        // Initializing the calendar Object
        Calendar cal = Calendar.getInstance();
 
        // Using the below pattern
        String new_pat = "MM/ dd/ yyyy HH:mm Z";
 
        // Use of applyPattern() method
        SDFormat.applyPattern(new_pat);
 
        // Displaying Current date and time
        String curr_date
            = SDFormat.format(cal.getTime());
        System.out.println("The Current Date: "
                           + curr_date);
 
        // Displaying the pattern
        System.out.println("Applied Pattern: "
                           + SDFormat.toPattern());
    }
}

输出：

The Current Date: 01/ 29/ 2019 07:22 +0000
Applied Pattern: MM/ dd/ yyyy HH:mm Z