如何在JAVA中检查对象的变量为空或NULL

Question

如何在JAVA中检查variables of Objects是empty or NULL？

Employee employee = repository.getEmployee(id).orElseGet(null);
if (employee == null) {
employee = new Employee();
employee.id(1);
employee.name("Thirumal");
employee.mobile("[phone]");
repository.save(employee);
}

我正在尝试创建一个对象new Employee()，而不是NULL

Employee employee = repository.getEmployee(id).orElseGet(new Employee());
if (employee.isEmpty()) { //--------- How to do ????????
employee = new Employee();
employee.id(1);
employee.name("Thirumal");
employee.mobile("[phone]");
repository.save(employee);
}

如何检查member of objects是empty/NULL？

Answer 1

只需将isEmpty方法添加到Employee类中并在那里实现它，或者使用null对象模式而不是执行new Employee()。

至于你实际上想在代码中做什么，我建议你这样做：

Employee employee = repository.getEmployee(id).orElseGet(() -> {
Employee emp = new Employee();
emp.id(1);
emp.name("Thirumal");
emp.mobile("[phone]");
return repository.save(emp);
});