java - 非 Spring 托管类上的 @Cacheable

Question

我需要在非 Spring 托管类上使用 ehcache，例如实用程序类。它不起作用。我尝试初始化实用程序类对象，但仍然没有成功。我要创建对象的原因是，这个特定的类不能是单例对象，因为这个类有一些其他类变量，这些变量的值与同一类的其他对象不同。所以我不能用 @Component

注释这个类

实用类

public class DirectoryReader implements IReader {

    // Some other class variables, which values are different from other object of same class Ex. Delete the file after read.
    private boolean deleteFilesAfterRead;
    @Cacheable(cacheNames="directoryContent", unless="#result.length() > 0")
    public String getContent() {
        //Read a file and get data;
        return "";
    }
}

对象创建

@Component
public class ReaderUtility {
    @Autowired
    ApplicationContext applicationContext;
    @Bean(name="readers")
    public List<IReader> determineReader() {
        DirectoryReader directoryReader1 = new DirectoryReader();
        DirectoryReader directoryReader2 = new DirectoryReader();
        applicationContext.getAutowireCapableBeanFactory().initializeBean(directoryReader1, "directoryReader1");
        applicationContext.getAutowireCapableBeanFactory().initializeBean(directoryReader2, "directoryReader2");
        // List<IReader> readers = .....
        // return readers;
    }
}

Answer 1

如果制作单例是问题所在，为什么不使用 @Scope("prototype")这样每个请求都会创建一个新的bean？对于像您的情况一样有状态的 bean，您应该这样做。

https://docs.spring.io/spring/docs/3.0.0.M3/reference/html/ch04s04.html#beans-factory-scopes-prototype

4.4.2 The prototype scope

The non-singleton, prototype scope of bean deployment results in the creation of a new bean instance every time a request for that specific bean is made (that is, it is injected into another bean or it is requested via a programmatic getBean() method call on the container). As a rule of thumb, you should use the prototype scope for all beans that are stateful, while the singleton scope should be used for stateless beans.

然后您可以将实用程序类更新为:

@Component
@Scope("prototype")
public class DirectoryReader implements IReader {

    // Some other class variables, which values are different from other object of same class Ex. Delete the file after read.
    private boolean deleteFilesAfterRead;
    @Cacheable(cacheNames="directoryContent", unless="#result.length() > 0")
    public String getContent() {
        //Read a file and get data;
        return "";
    }
}