Java Data Type - 如何将长度为1的字符串转换为ASCII代码(0-255)的关联int值

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {
  public static void main(String args[]) throws IOException {
    BufferedReader buff = new BufferedReader(new InputStreamReader(System.in));
    System.out.println("Enter the char:");
    String str = buff.readLine();
    for (int i = 0; i < str.length(); ++i) {
      char c = str.charAt(i);
      int j = (int) c;
      System.out.println("ASCII OF " + c + " = " + j + ".");
    }
  }

}