Java BreakIterator preceding()用法及代码示例

java.text.BreakIterator类的preceding()方法用于获取指定字符偏移量边界之前的最后一个边界的字符索引。它提供了由BreakIterator指向的当前边界之后或之前的边界第一个字符的偏移量。

用法:

public int preceding(int offset)

参数：它使用必须找到先前边界的字符的偏移量。

返回值：此方法提供在指定字符偏移量之前的边界索引。

异常：如果指定的索引小于第一个文本边界或大于最后一个文本边界，则此方法引发IllegalArgumentException。

下面是说明preceding()方法的示例：

示例1:

// Java program to demonstrate preceding() method 
  
import java.text.*; 
import java.util.*; 
import java.io.*; 
  
public class GFG { 
    public static void main(String[] argv) 
    { 
        // creating and initializing with zero 
        int current = 0, next = 0; 
  
        // creating and initializing BreakIterator 
        BreakIterator wb 
            = BreakIterator.getWordInstance(); 
  
        // setting text for BreakIterator 
        wb.setText("Code  Geeks"); 
  
        // setting the current position to 11 
        // by skipping 3 boundaries 
        wb.next(3); 
  
        // getting the current text boundary 
        current = wb.current(); 
  
        // display the result 
        System.out.println( 
            "current position before"
            + " calling preceding() : "
            + current); 
  
        // calling preceding() method 
        next = wb.preceding(6); 
  
        // display the result 
        System.out.println( 
            "\ncurrent position after"
            + " calling 1st preceding() : "
            + next); 
  
        // calling preceding() method 
        next = wb.preceding(11); 
  
        // display the result 
        System.out.println( 
            "\ncurrent position after"
            + " calling 2nd preceding() : "
            + next); 
    } 
}

输出：

current position before calling preceding() : 11

current position after calling 1st preceding() : 4

current position after calling 2nd preceding() : 6

示例2:

// Java program to demonstrate preceding() method 
  
import java.text.*; 
import java.util.*; 
import java.io.*; 
  
public class GFG { 
    public static void main(String[] argv) 
    { 
        try { 
            // creating and initializing with zero 
            int current = 0, next = 0; 
  
            // creating and initializing BreakIterator 
            BreakIterator wb 
                = BreakIterator.getWordInstance(); 
  
            // setting text for BreakIterator 
            wb.setText("Code  Geeks"); 
  
            // setting the current position to 11 
            // by skipping 3 boundaries 
            wb.next(3); 
  
            // getting the current text boundary 
            current = wb.current(); 
  
            // display the result 
            System.out.println( 
                "current position before"
                + " calling preceding() : "
                + current); 
  
            // calling preceding() method 
            next = wb.preceding(6); 
  
            // display the result 
            System.out.println( 
                "\ncurrent position after"
                + " calling 1st preceding() : "
                + next); 
  
            // calling preceding() method 
            next = wb.preceding(-1); 
  
            // display the result 
            System.out.println( 
                "\ncurrent position after"
                + " calling 2nd preceding() : "
                + next); 
        } 
        catch (IllegalArgumentException e) { 
  
            System.out.println( 
                "\noffset is less than the first boundary"); 
            System.out.println("Exception thrown : " + e); 
        } 
    } 
}

输出：

current position before calling preceding() : 11

current position after calling 1st preceding() : 4

offset is less than the first boundary
Exception thrown : java.lang.IllegalArgumentException: offset out of bounds

参考： https://docs.oracle.com/javase/9/docs/api/java/text/BreakIterator.html#preceding-int-

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注：本文由纯净天空筛选整理自RohitPrasad3大神的英文原创作品 BreakIterator preceding() method in Java with Examples。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。