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

Character.isJavaIdentifierStart(int codePoint)是Java中的一种内置方法，它确定字符(Unicode代码点)是否被允许作为Java标识符中的第一个字符。要注意的是，当且仅当以下条件之一为真时，字符才能开始Java标识符：

isLetter(ch)返回true
getType(ch)返回LETTER_NUMBER
ch是货币符号(例如“ $”)
ch是连接的标点字符(例如“ _”)。

用法:

public static boolean isJavaIdentifierStart(int codePoint)

参数：参数codePoint是整数类型，它表示要测试的字符(Unicode代码点)。

返回值：如果字符可以启动Java标识符，则Character类的isJavaIdentifierStart(int codePoint)方法返回true。否则为假。

以下示例程序旨在说明Character.isJavaIdentifierStart()方法：

示例1:

// Java program to illustrate 
// Character.isJavaIdentifierStart() method  
import java.lang.*; 
  
public class gfg { 
  
    public static void main(String[] args) 
    { 
  
        // Create 2 int primitives c1, c2 
        int c1 = 0x0039, c2 = 0x004b, c3 = 0x0081; 
  
        // Assign isJavaIdentifierPart results of  
        // c1, c2 to boolean primitives bool1, bool2 
  
        boolean bool1 = Character.isJavaIdentifierStart(c1); 
        boolean bool2 = Character.isJavaIdentifierStart(c2); 
        boolean bool3 = Character.isJavaIdentifierStart(c3); 
  
        String str1 = "c1 may start a Java identifier is " + bool1; 
        String str2 = "c2 may start a Java identifier is " + bool2; 
        String str3 = "c3 may start a Java identifier is " + bool3; 
  
        // Print bool1, bool2 values 
        System.out.println(str1); 
        System.out.println(str2); 
        System.out.println(str3); 
    } 
}

输出：

c1 may start a Java identifier is false
c2 may start a Java identifier is true
c3 may start a Java identifier is false

示例2:

// Java program to illustrate 
// Character.isJavaIdentifierStart() method  
import java.lang.*; 
  
public class gfg { 
  
    public static void main(String[] args) 
    { 
  
        // Create 2 int primitives c1, c2 
        int c1 = 0x0034, c2 = 0x005a; 
  
        // Assign isJavaIdentifierPart results of  
        // c1, c2 to boolean primitives bool1, bool2 
  
        boolean bool1 = Character.isJavaIdentifierStart(c1); 
        boolean bool2 = Character.isJavaIdentifierStart(c2); 
  
        String str1 = "c1 may start a Java identifier is " + bool1; 
        String str2 = "c2 may start a Java identifier is " + bool2; 
  
        // Print bool1, bool2 values 
        System.out.println(str1); 
        System.out.println(str2); 
    } 
}

输出：

c1 may start a Java identifier is false
c2 may start a Java identifier is true

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

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注：本文由纯净天空筛选整理自Twinkl Bajaj大神的英文原创作品 Character.isJavaIdentifierStart() Method in Java。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。