Java StringBuffer offsetByCodePoints() 方法

Java StringBuffer offsetByCodePoints() 方法用于检索此序列中从给定索引偏移 codePointOffset 个代码点的索引值。

此方法返回序列字符的代码点值的流。流包含整数代码点值，类似于 Java 中的ASCII 值。

offsetByCodePoints() 方法接受两个整数参数，分别保存索引和codePointOffset的值。如果索引值小于0或大于序列长度，等等，它会抛出不同的异常。

语法

以下是Java StringBuffer offsetByCodePoints() 方法的语法：

public int offsetByCodePoints(int index, int codePointOffset)

参数

• index − 要偏移的索引。

• codePointOffset − 代码点的偏移量。

返回值

此方法返回此序列中的索引。

示例：获取代码点偏移量

如果给定的索引值为正数且小于序列长度，则 offsetByCodePoint() 方法返回索引值。

在下面的程序中，我们使用值为“TutorialsPoint”创建StringBuffer 类的对象。使用offsetByCodePoints()，我们尝试获取指定startIndex 2和codePointOffset 5处的索引值。

public class OffsetCodePoint {
   public static void main(String[] args) {
      //create an object of the StringBuffer class
      StringBuffer sb = new StringBuffer("TutorialsPoint");
      System.out.println("The given String is: " + sb);
      //initialize the index and codePointOffset values
      int index = 2;
      int codePointOffset = 5;
      System.out.println("The given index and code point offset values are: " + index + " and " + codePointOffset);
      //using the offsetByCodePoint() method
      System.out.println("The index is: " + sb.offsetByCodePoints(index, codePointOffset));
   }
}

输出

执行上述程序后，将产生以下结果：

The given String is: TutorialsPoint
The given index and code point offset values are: 2 and 5
The index is: 7

示例：获取代码点偏移量时遇到 IndexOutOfBoundsException

如果给定的索引值为负数且大于序列长度，则 offsetByCodePoint() 方法将抛出 IndexOutOfBoundsException。

在下面的程序中，我们使用值为“Java Programming”实例化StringBuffer 类。使用offsetByCodePoints() 方法，我们尝试获取指定index -1和codePointOffset 5处的索引值。

public class OffsetCodePoint {
   public static void main(String[] args) {
      try {
         //instantiate the StringBuffer class
         StringBuffer sb = new StringBuffer("Java Programming");
         System.out.println("The given String is: " + sb);
         //initialize the index and codePointOffset values
         int index = -1;
         int codePointOffset = 5;
         System.out.println("The given index and code point offset values are: " + index + " and " + codePointOffset);
         //using the offsetByCodePoint() method
         System.out.println("The index is: " + sb.offsetByCodePoints(index, codePointOffset));
      } catch(IndexOutOfBoundsException e) {
         e.printStackTrace();
         System.out.println("Exception e: " + e);
      }
   }
}

输出

以下是上述程序的输出：

The given String is: Java Programming
The given index and code point offset values are: -1 and 5
java.lang.IndexOutOfBoundsException
   at java.base/java.lang.AbstractStringBuilder.offsetByCodePoints(AbstractStringBuilder.java:461)
   at java.base/java.lang.StringBuffer.offsetByCodePoints(StringBuffer.java:279)
   at OffsetCodePoint.main(OffsetCodePoint.java:15)
Exception e: java.lang.IndexOutOfBoundsException

示例：获取代码点偏移量时遇到 IndexOutOfBoundsException

如果给定的索引值大于序列长度，此方法将抛出IndexOutOfBoundException。

在下面的示例中，我们使用值为“Hello”创建一个StringBuffer。使用offsetByCodePoints() 方法，我们尝试获取指定startIndex 10和codePointOffset 2处的索引值。

public class OffsetCodePoint {
   public static void main(String[] args) {
      try {
         //instantiate the StringBuffer class
         StringBuffer sb = new StringBuffer("Hello");
         System.out.println("The given String is: " + sb);
         //initialize the index and codePointOffset values
         int index = 10;
         int codePointOffset = 2;
         System.out.println("The given index and code point offset values are: " + index + " and " + codePointOffset);
         //using the offsetByCodePoint() method
         System.out.println("The index is: " + sb.offsetByCodePoints(index, codePointOffset));
      } catch(IndexOutOfBoundsException e) {
         e.printStackTrace();
         System.out.println("Exception e: " + e);
      }
   }
}

输出

上述程序产生以下输出：

The given String is: Hello
The given index and code point offset values are: 10 and 2
java.lang.IndexOutOfBoundsException
   at java.base/java.lang.AbstractStringBuilder.offsetByCodePoints(AbstractStringBuilder.java:461)
   at java.base/java.lang.StringBuffer.offsetByCodePoints(StringBuffer.java:279)
   at OffsetCodePoint.main(OffsetCodePoint.java:15)
Exception e: java.lang.IndexOutOfBoundsException