Java Character.isIdentifierIgnorable()用法及代码示例

1. java.lang.Character.isIdentifierIgnorable(char ch)是java中的一种内置方法，该方法确定应将指定字符视为Java标识符还是Unicode标识符中的可忽略字符。

   以下Unicode字符在Java标识符或Unicode标识符中可忽略：

   • 非空白的ISO控制字符
     1. “ \ u0000”到“ \ u0008”
     2. “ \ u000E”到“ \ u001B”
     3. 从'\ u007F'到'\ u009F'
   • 具有FORMAT常规类别值的所有字符

   用法:

   
   

   public static boolean isIdentifierIgnorable(char ch)

   参数：参数ch是字符数据类型，是指要测试的字符。

   返回值：如果该字符是Java或Unicode标识符的一部分的可忽略控制字符，则此方法返回true，否则返回false。

   以下示例程序旨在说明Character.isIdentifierIgnorable(char ch)方法：

   示例1:

   // Java program to illustrate 
   // Character.isIdentifierIgnorable(char ch) method 
   import java.lang.*; 
     
   public class gfg { 
     
      public static void main(String[] args) { 
     
         // Creates 2 character primitives c1, c2 and assigning values 
         char c1='\u0000', c2= '9'; 
     
         // Assigns isIdentifierIgnorable results of  
         // c1, c2 to boolean primitives 
         boolean  bool1 = Character.isIdentifierIgnorable(c1); 
         boolean  bool2 = Character.isIdentifierIgnorable(c2); 
     
         String str1 = "c1 is an ignorable control character is " + bool1; 
         String str2 = "c2 is an ignorable control character is " + bool2; 
     
         System.out.println( str1 ); 
         System.out.println( str2 ); 
      } 
   }

   输出：

   c1 is an ignorable control character is true
   c2 is an ignorable control character is false
   

   示例2:

   import java.lang.*; 
     
   public class gfg { 
     
      public static void main(String[] args) { 
     
         // Create 2 character primitives c1, c2 and assigning values 
         char c1='\u000E', c2= '8'; 
     
         // Assigns isIdentifierIgnorable results of  
         // c1, c2 to boolean primitives 
         boolean  bool1 = Character.isIdentifierIgnorable(c1); 
         boolean  bool2 = Character.isIdentifierIgnorable(c2); 
     
         String str1 = "c1 is an ignorable control character is " + bool1; 
         String str2 = "c2 is an ignorable control character is " + bool2; 
     
         System.out.println( str1 ); 
         System.out.println( str2 ); 
      } 
   }

   输出：

   c1 is an ignorable control character is true
   c2 is an ignorable control character is false
   

2. java.lang.Character.isIdentifierIgnorable(int codePoint)在所有方面都类似于先前的方法。

   用法:

   public static boolean isIdentifierIgnorable(int codePoint)
   

   参数：该函数接受整数数据类型的单个参数codePoint，该参数指定要测试的字符(Unicode代码点)。

   返回值：如果该字符是Java或Unicode标识符的一部分的可忽略控制字符，则此方法返回true，否则返回false。

   
   

   以下示例程序旨在说明Character.isIdentifierIgnorable(int codepoint)方法：
   示例1:

   // Java program to demonstrate  
   // the Character.isIdentifierIgnorable(int codepoint) method 
     
   import java.lang.*; 
     
   public class gfg { 
     
      public static void main(String[] args) { 
     
         // Integer primitives c1, c2 
         int c1 = 0x019f, c2 = 0x1abc; 
     
         // Assign isIdentifierIgnorable results of cp1, cp2 
         // to boolean primitives bool1, bool2 
        boolean bool1 = Character.isIdentifierIgnorable(c1); 
        boolean bool2 = Character.isIdentifierIgnorable(c2); 
     
         // Print bool1, bool2 values 
         System.out.println( "c1 is an ignorable control character?"+ 
         " ans is "+bool1); 
         System.out.println( "c2 is an ignorable control character?"+ 
         " ans is "+bool2); 
      } 
   }

   输出：

   c1 is an ignorable control character? ans is false
   c2 is an ignorable control character? ans is false
   

   示例2:

   // Java program to demonstrate  
   // the Character.isIdentifierIgnorable(int codepoint) method 
     
   import java.lang.*; 
     
   public class gfg { 
     
      public static void main(String[] args) { 
     
         // Integer primitives c1, c2 
         int c1 = 0x119f, c2 = 0x0abc; 
     
         // Assign isIdentifierIgnorable results of cp1, cp2 
         // to boolean primitives bool1, bool2 
        boolean bool1 = Character.isIdentifierIgnorable(c1); 
        boolean bool2 = Character.isIdentifierIgnorable(c2); 
     
         // Print bool1, bool2 values 
         System.out.println( "c1 is an ignorable control character?"+ 
         " ans is "+bool1); 
         System.out.println( "c2 is an ignorable control character?"+ 
         " ans is "+bool2); 
      } 
   }

   输出：

   c1 is an ignorable control character? ans is false
   c2 is an ignorable control character? ans is false
   

参考： https://docs.oracle.com/javase/7/docs/api/java/lang/Character.html#isIdentifierIgnorable(char)