Java StringBuilder codePointBefore（）方法与示例

StringBuilder类codePointBefore()方法 (StringBuilder Class codePointBefore() method)

codePointBefore() method is available in java.lang package.
codePointBefore()方法在java.lang包中可用。
codePointBefore() method is used to represent the Unicode code point before the given index and array indexing starts from 0 to length() - 1.
codePointBefore()方法用于表示给定索引和数组索引从0开始到length()-1之前的Unicode代码点。
codePointBefore() method is a non-static method, it is accessible with the class object only and if we try to access the method with the class name then we will get an error.
codePointBefore()方法是一个非静态方法，只能使用类对象访问，如果尝试使用类名称访问该方法，则会收到错误消息。
codePointBefore() method may throw an exception at the time of assigning index.
在分配索引时， codePointBefore()方法可能会引发异常。

IndexOutOfBoundsException - This exception may throw when the given argument value is not less than the length or denotes negative value.
IndexOutOfBoundsException-当给定的参数值不小于长度或表示负值时，可能引发此异常。

Syntax:

句法：

    public int codePointBefore(int indices)

Parameter(s):

参数：

int indices – represents the index of following the Unicode code point that should be retrieved.
int index –表示应检索的Unicode代码点之后的索引。

Return value:

返回值：

The return type of this method is int, t returns the Unicode code point before the given indices.

此方法的返回类型为int ，t返回给定索引之前的Unicode代码点。

Example:

例：

// Java program to demonstrate the example 
// of int codePointBefore(int indices) method of StringBuilder 
public class CodePointBefore {
public static void main(String[] args) {
// Creating an StringBuilder object
StringBuilder st_b = new StringBuilder("Java");
System.out.println("st_b = " + st_b);
// By using codePointBefore(2) method is to return the codepoint
// at before the given index 2 i.e. it returns codepoint at 
// following the given index i.e index 1
int cp = st_b.codePointBefore(2);
// Display codepoint value at before the given index 2
System.out.println("st_b.codePointBefore(2)=" + cp);
}
}

Output

输出量