java equals()方法防止空指针异常

以前使用equals()方法总是担心报空指针异常，在调用equals()之前还得对变量判空，直到发现了Objects.equals()方法…

public static void main(String[] args) {

    String a = null;
    String b = "a";

    System.out.println(Objects.equals(a, b));
    try {
      System.out.println(a.equals(b));
    } catch (NullPointerException e) {
      System.out.println("空指针异常");
    }

  }

打印结果

false
空指针异常

Process finished with exit code 0