将br作为参数传递的隐患

public int[][] plusFromConsole() {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        int a[][] = getFromConsole(br);
        return plus(a, getFromConsole(br));
    }
public static int[][] getFromConsole(BufferedReader br) {
        try {

            String s = br.readLine();
            String[] strings = s.split(" ");

public void testPlusFromConsole4() {
        String input = "0 0" + NL + "0 0" + NL;

为什么在plusFromConsole中br.readline为“0 0”而在getFromConsole函数中s为null

```

你只能在一个地方执行readLine，执行一次之后，缓冲区里的数据就被读走了呀