String name = "admin";
char[] ch = name.toString().toCharArray(); //it will read and store each character of String and store into char[].

for(int i=0; i<ch.length; i++)
{
    System.out.println(ch[i]+
                       "-->"+
                       (int)ch[i]); //this will print both character and its value
}

如果你想要一个字符串中所有字符的ASCII值。你可以用这个:

String a ="asdasd";
int count =0;
for(int i : a.toCharArray())
    count+=i;

如果你想要字符串中单个字符的ASCII码，你可以使用:

(int)a.charAt(index);

非常简单。只需将char类型转换为int类型。

char character = 'a';    
int ascii = (int) character;

在本例中，您需要首先从String中获取特定的字符，然后强制转换它。

char character = name.charAt(0); // This gives the character 'a'
int ascii = (int) character; // ascii is now 97.

虽然没有明确要求强制转换，但它提高了可读性。

int ascii = character; // Even this will do the trick.

String name = "admin";
char[] ch = name.toString().toCharArray(); //it will read and store each character of String and store into char[].

for(int i=0; i<ch.length; i++)
{
    System.out.println(ch[i]+
                       "-->"+
                       (int)ch[i]); //this will print both character and its value
}

或者你可以使用流API为一个字符或从Java 1.8开始的字符串:

public class ASCIIConversion {
    public static void main(String[] args) {
        String text = "adskjfhqewrilfgherqifvehwqfjklsdbnf";
        text.chars()
                .forEach(System.out::println);
    }
}

public class Ascii {
    public static void main(String [] args){
        String a=args[0];
        char [] z=a.toCharArray();
        for(int i=0;i<z.length;i++){ 
            System.out.println((int)z[i]);
        }
    }
}