为什么从非bean类的方法调用可缓存方法时@Cacheable不起作用

Question

当我从非 bean 类内部的方法调用可缓存方法时，我突然发现 @Cacheable 不起作用。

请在下面找到我的代码并帮助我解决问题或我想念的东西。

EmployeeDAO.java

@Component("employeeDAO")
public class EmployeeDAO {
private static EmployeeDAO staticEmployeeDAO;

public static EmployeeDAO getInstance(){
    return staticEmployeeDAO;
}

@PostConstruct
void initStatic(){
    staticEmployeeDAO = this;
}

@Cacheable(value = "employeeCache")
public List<Employee> getEmployees() {
    Random random = new Random();
    int randomid = random.nextInt(9999);
    System.out.println("*** Creating a list of employees and returning the list ***");
    List<Employee> employees = new ArrayList<Employee>(5);
    employees.add(new Employee(randomid, "Ben", "Architect"));
    employees.add(new Employee(randomid + 1, "Harley", "Programmer"));
    employees.add(new Employee(randomid + 2, "Peter", "BusinessAnalyst"));
    employees.add(new Employee(randomid + 3, "Sasi", "Manager"));
    employees.add(new Employee(randomid + 4, "Abhi", "Designer"));
    return employees;
}    

MyThread.java

class MyThread{
public void run(){
    //How to get Employee data. ?????
}
}    

UtilityClass.java

public class UtilityClass {
public static void getEmployee(){
    EmployeeDAO.getInstance().getEmployees();
}
}    

Main.java

public class Main {


public static void main(String[] args) {

    ApplicationContext context = new ClassPathXmlApplicationContext("spring-config.xml");
    EmployeeDAO dao = (EmployeeDAO)context.getBean("employeeDAO");

    System.out.println("1'st call");
    dao.getEmployees();
    System.out.println("2'nd call");
    dao.getEmployees();
    System.out.println("Call cache method using utility class");

    System.out.println("1'st call on utilityclass");
    UtilityClass.getEmployee();
    System.out.println("2'nd call on utilityclass");
    UtilityClass.getEmployee();
}
}    

输出：

1'st call
*** Creating a list of employees and returning the list ***
2'nd call
Call cache method using utility class
1'st call on utilityclass
*** Creating a list of employees and returning the list ***
2'nd call on utilityclass
*** Creating a list of employees and returning the list ***  

谁能帮帮我？

Answer 1

Spring 使用代理来应用 AOP，但是代理是在构建 bean 之后创建的。

在您的 @PostConstruct 注释方法中，您正在设置对 this 的引用，但此时这是 bean 的未代理实例。你真的需要代理实例。

我还要指出，恕我直言，您的解决方案非常糟糕，无法通过我的 QA 检查。但那是恕我直言。