Java中的 DateFormat parse( 字符串 , ParsePosition) 方法及示例

Java.text 包的 DateFormat 类是一个抽象类，用于格式化和解析任何语言环境的日期。它允许我们将日期格式化为文本并将文本解析为日期。 DateFormat 类提供了许多功能来获取、格式化、解析默认日期/时间。

Note: DateFormat class extends Format class that means it is a subclass of Format class. Since DateFormat class is an abstract class, therefore, it can be used for date/time formatting subclasses, which format and parses dates or times in a language-independent manner.  

包视图：

java.text Package
    DateFormat Class
        parse(string , ParsePosition) Method

DateFormat 类的parse(String the_text , ParsePosition position )方法用于从字符串中解析文本以生成日期。该方法从起始位置给定的索引开始解析文本。

句法：

public abstract Date parse(String the_text, ParsePosition position)

参数：它需要2个参数：

• the_text ：这是String类型，指的是要解析以生成日期的字符串。
• position ：这是ParsePosition对象类型，是指解析的起始索引的信息。

返回类型：返回从字符串解析的日期，如果出错则返回 Null。

示例 1：

Java

// Java Program to Illustrate parse() Method
// of DateFormat Class
 
// Importing required classes
import java.text.*;
import java.util.Calendar;
 
// Main class
public class GFG {
 
    // Main driver method
    public static void main(String[] args)
    {
        // Creating object of DateFormat class inside main()
        DateFormat DFormat
            = new SimpleDateFormat("MM/ dd/ yy");
 
        // Try block to check for exceptions
        try {
 
            Calendar cal = Calendar.getInstance();
 
            // Parsing date From string
            // using parse() method of DateFormat class
 
            // Custom string date
            String dt = "10/ 27/ 16";
 
            // Printing the above unparsed date
            System.out.println("The unparsed"
                               + " string is: " + dt);
 
            // Parsing date using parse() method
            cal.setTime(DFormat.parse(dt));
 
            // Printing the parsed time
            System.out.println("Time parsed: "
                               + cal.getTime());
        }
 
        // Catch block to handle exceptions
        catch (ParseException except) {
 
            // Display exceptions with line number
            // using printStackTrace() method
            except.printStackTrace();
        }
    }
}

输出：

The unparsed string is: 10/ 27/ 16
Time parsed: Thu Oct 27 00:00:00 UTC 2016

示例 2：

Java

// Java Program to Illustrate parse() Method
// of DateFormat Class
 
// Importing required classes
import java.text.*;
import java.util.Calendar;
 
// Main class
public class GFG {
 
    // Main driver method
    public static void main(String[] args)
    {
 
        // Creating an object of DateFormat class
        DateFormat DFormat
            = new SimpleDateFormat("MM/ dd/ yy");
 
        // Try bloc kto check for exceptions
        try {
 
            // Getting instance from calendar
            Calendar cal = Calendar.getInstance();
 
            // Parsing date from string
            // using parse() method
            String dt = "01/ 29/ 19";
 
            // Displaying the unparsed date
            System.out.println("The unparsed"
                               + " string is: " + dt);
 
            // Parsing date
            cal.setTime(DFormat.parse(dt));
            System.out.println("Time parsed: "
                               + cal.getTime());
        }
 
        // Catch block to handle the exceptions
        catch (ParseException except) {
 
            // Display exception with line number
            // using printStackTrace() method
            except.printStackTrace();
        }
    }
}

输出

The unparsed string is: 01/ 29/ 19
Time parsed: Tue Jan 29 00:00:00 UTC 2019