Java中的 FieldPosition getBeginIndex() 方法与示例

Java.text.FieldPosition类的getBeginIndex()方法用于获取FieldPosition 对象的起始字符的索引。

句法：

public int getBeginIndex()

参数：此方法不接受任何参数作为参数。

返回值：该方法返回 FieldPosition 对象的起始字符的索引。

以下是说明getBeginIndex()方法的示例：

示例 1：

Java

// Java program to demonstrate
// getBeginIndex() method
 
import java.text.*;
import java.util.*;
import java.io.*;
 
public class GFG {
    public static void main(String[] argv)
    {
        try {
 
            // Creating and initializing
            /// new FieldPosition Object
            FieldPosition pos
                = new FieldPosition(
                    DateFormat.Field.AM_PM);
 
            // getting begin index of FieldPosition Object
            // using getBeginIndex() method
            int i = pos.getBeginIndex();
 
            // display result
            System.out.println("begin index :- " + i);
        }
 
        catch (ClassCastException e) {
 
            System.out.println("Exception thrown : " + e);
        }
    }
}

输出：

begin index :- 0

示例 2：

Java

// Java program to demonstrate
// getBeginIndex() method
 
import java.text.*;
import java.util.*;
import java.io.*;
 
public class GFG {
    public static void main(String[] argv)
    {
        try {
 
            // Creating and initializing
            // new FieldPosition Object
            FieldPosition pos
                = new FieldPosition(
                    DateFormat.Field.AM_PM);
 
            // setting begin index
            pos.setBeginIndex(5);
 
            // getting begin index of FieldPosition Object
            // using getBeginIndex() method
            int i = pos.getBeginIndex();
 
            // display result
            System.out.println("begin index :- " + i);
        }
 
        catch (ClassCastException e) {
 
            System.out.println("Exception thrown : " + e);
        }
    }
}

输出：

begin index :- 5

参考： https://docs.oracle.com/javase/9/docs/api/ Java/text/FieldPosition.html#setBeginIndex-int-