Java BreakIterator previous()方法及示例

java.text.BreakIterator 类的 previous() 方法是用来获取当前边界（通过调用current()方法获取的边界）后面的前一个边界的索引。它提供了BreakIterator指向的当前边界之前的边界的第一个字符的偏移。

语法

public abstract int previous()

参数： 该方法不接受任何参数。

返回值： 该方法提供了当前边界之后的前一个边界的 索引 。

下面是说明 previous() 方法的例子。

例1 :

// Java program to demonstrate previous() 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 index 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 previous() : "            + current);          // calling previous() method        next = wb.previous();          // display the result        System.out.println(            "\ncurrent position after"            + " calling 1st previous() : "            + next);          // calling previous() method        next = wb.previous();          // display the result        System.out.println(            "\ncurrent position after"            + " calling 2nd previous() : "            + next);    }}

输出:

current position before calling previous() : 11current position after calling 1st previous() : 6current position after calling 2nd previous() : 4

例2 :

// Java program to demonstrate// previous() 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("GeeksForGeeks");          // setting the current position to index 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 previous() : "            + current);          // calling previous() method        next = wb.previous();          // display the result        System.out.println(            "\ncurrent position after"            + " calling 1st previous() : "            + next);          // calling previous() method        next = wb.previous();          // display the result        System.out.println(            "\ncurrent position after"            + " calling 2nd previous() : "            + next);    }}

输出:

current position before calling previous() : 13current position after calling 1st previous() : 0current position after calling 2nd previous() : -1

参考资料: https://docs.oracle.com/javase/9/docs/api/java/text/BreakIterator.html#previous-