两个线程，一个输出字母一个输出数字，输出A1B2C3....Z26

思路1 ：用一个变量记录属于哪个线程执行，然后另外一个线程阻塞掉即可。

public class main {
    static volatile int a = 1;
    public static void main(String[] args) {
        new  Thread(new Runnable() {
            @Override
            public void run() {
                for(int i = 0 ; i < 26 ; i++){
                    while(a % 2 == 1){
                        try {
                            Thread.currentThread().interrupt();
                        } catch (Exception e) {
                            e.printStackTrace();
                        }
                    }
                    System.out.println(a/2);
                    a = a+1;
                }
            }
        }).start();
        new  Thread(new Runnable() {
            @Override
            public void run() {
                for(int i = 0 ; i < 26 ; i++){
                    while(a % 2 == 0){
                        try {
                            Thread.currentThread().interrupt();
                        } catch (Exception e) {
                            e.printStackTrace();
                        }
                    }
                    System.out.println((char)((a/2)+'A'));
                    a = a+1;
                }
            }
        }).start();
    }
}