我知道这个问题已经以几种形式回答了，但这里是我的一点代码，看看所有的字符。

下面是代码，从类开始

public class CheckChValue {  // Class name
public static void main(String[] args) { // class main

    String name = "admin"; // String to check it's value
    int nameLenght = name.length(); // length of the string used for the loop

    for(int i = 0; i < nameLenght ; i++){   // while counting characters if less than the length add one        
        char character = name.charAt(i); // start on the first character
        int ascii = (int) character; //convert the first character
        System.out.println(character+" = "+ ascii); // print the character and it's value in ascii
    }
}

}

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.

最简单的方法是:

对于整个字符串转换成ASCII:

public class ConvertToAscii{
    public static void main(String args[]){
      String abc = "admin";
      int []arr = new int[abc.length()];
      System.out.println("THe asscii value of each character is: ");
      for(int i=0;i<arr.length;i++){
          arr[i] = abc.charAt(i); // assign the integer value of character i.e ascii
          System.out.print(" "+arr[i]);
      }
    }
}

输出结果为:

每个字符的asscii值为: 97 100 109 105 110 这里，abc.charAt(i)给出了String数组的单个字符: 当我们将每个字符赋值为整型时，编译器会进行类型转换，

arr[i] = (int) character //这里，每个单独的字符都是ascii值

但是，对于单个字符:

字符串名称= admin; asciiValue = (int) name.charAt(0);//字符'a' System.out.println (asciiValue);

为此，我们可以直接使用String类

    input.codePointAt(index);

我想再给出一个建议，以获得整个字符串转换为相应的ascii码，使用java 8 例如:“abcde”~“979899100101”。

    String input = "abcde";
    System.out.println(
            input.codePoints()
                    .mapToObj((t) -> "" + t)
                    .collect(joining()));

String str = "abc";  // or anything else

// Stores strings of integer representations in sequence
StringBuilder sb = new StringBuilder();
for (char c : str.toCharArray())
    sb.append((int)c);

 // store ascii integer string array in large integer
BigInteger mInt = new BigInteger(sb.toString());
System.out.println(mInt);

而不是这样:

String char = name.substring(0,1); //char="a"

您应该使用charAt()方法。

char c = name.charAt(0); // c='a'
int ascii = (int)c;