打印 ASCII 值的Java程序

ASCII 是代表美国信息交换标准代码的首字母缩写词。在 ASCII 中，特定的数值被赋予不同的字符和符号，供计算机存储和操作，并且在存储和操作电子设备时始终使用给定的 ASCII 数字的二进制值。因为在原始形式中不可能做到这一点。

方法：有4种方法可以打印特定字符的ASCII值或代码，下面列出了概念，然后是实现部分的Java示例。

1. 使用蛮力法
2. 使用类型转换方法
3. 使用格式说明符方法
4. 使用字节类方法

方法一：给int变量赋值

为了找到字符字符给一个新的整数类型变量。 Java会自动将该字符的 ASCII 值存储在新变量中。

实施：蛮力法

Java

// Java program to print ASCII Value of Character
// by assigning variable to integer
  
public class GFG {
  
    // Main driver method
    public static void main(String[] args)
    {
        // Character whose ASCII is to be computed
        char ch = '}';
  
        // Creating a new variable of type int
        // and assigning the character value.
        int ascii = ch;
  
        /* Java stores the ascii value there itself*/
  
        // Printing the ASCII value of above character
        System.out.println("The ASCII value of " + ch
                           + " is: " + ascii);
    }
}

输出

The ASCII value of } is: 125

方法 2：使用类型转换

Java中的类型转换是一种将变量转换为另一种数据类型的方法，这意味着持有另一种数据类型的值占用较少的字节。在这种方法中，字符在打印时是 char 类型到 int 类型的类型转换，它将打印字符的 ASCII 值。

Java

// Java program to print ASCII Value of Character
// using type-casting
  
// Importing java generic libraries
import java.util.*;
  
public class GFG {
  
    // Main driver method
    public static void main(String[] args)
    {
        // Character whose ASCII is to be computed
        char ch = '}';
  
        // Typecasting the character to int and
        // printing the same
        System.out.println("The ASCII value of " + ch
                           + " is: " + (int)ch);
    }
}

输出

The ASCII value of } is: 125

Note: In above method 1 and method 2, both the methods are one type of typecasting. In method 1, typecasting is done automatically by the compiler. In method 2, typecasting it manually so the method 2 is much more efficient than method 1 as the compiler has to put lesser effort. Also, remember typecasting done automatically is called implicit typecasting and where it is done from the user end is called explicit typecasting 

方法 3：使用格式说明符（更优）

在这种方法中，我们在格式说明符的帮助下生成给定字符的 ASCII 值。我们通过将字符指定为 int 来将给定字符的值存储在形式说明符中。因此，该字符的 ASCII 值存储在格式说明符中。

Java

// Java program to print ASCII Value of Character
// using format specifier
  
// Importing format library
import java.util.Formatter;
  
public class GFG {
  
    // Main driver method
    public static void main(String[] args)
    {
        // Character whose ASCII is to compute
        char character = '}';
  
        // Initializing the format specifier
        Formatter formatSpecifier = new Formatter();
  
        // Converting the character to integer and
        // ASCII value is stored in the format specifier
        formatSpecifier.format("%d", (int)character);
  
        // Print the corresponding ASCII value
        System.out.println(
            "The ASCII value of the character ' "
            + character + " ' is " + formatSpecifier);
    }
}

输出

The ASCII value of the character ' } ' is 125

方法 4：通过生成字节查找 ASCII 值（最优化）

1. 将字符初始化为字符串。
2. 使用 getBytes() 方法创建字节类型的数组。
3. 在字节数组的第 '0' 个索引处打印元素。

这是位于字符串第 0 个索引处的字符的 ASCII 值。此方法通常用于将整个字符串转换为其 ASCII 值。对于违反编码异常的字符，给出try-catch。

Java

// Java program to print ASCII Value of Character
// by generating bytes. 
  
// Importing I/O library
import java.io.UnsupportedEncodingException;
  
public class GFG {
  
    // Main driver method
    public static void main(String[] args)
    {
        // Try block to check exception
        try {
  
            // Character is initiated as a string
            String sp = "}";
  
            // An array of byte type is ccreated
            // by using getBytes method
            byte[] bytes = sp.getBytes("US-ASCII");
  
            /*This is the ASCII value of the character
            / present at the '0'th index of above string.*/
  
            // Printing the element at '0'th index
            // of array(bytes) using charAt() method
            System.out.println("The ASCII value of "
                               + sp.charAt(0) + " is "
                               + bytes[0]);
        }
  
        // Catch block to handle exception
        catch (UnsupportedEncodingException e) {
  
            // Message printed foe exception
            System.out.println("OOPs!!!UnsupportedEncodingException occurs.");
        }
    }
}

输出

The ASCII value of } is 125