将弹簧从3.2升级到4 - 泛型（扩展）问题 [英] Upgrading spring from 3.2 to 4 - Issue with generics (extends)

问题描述

我有以下与spring 3.2一起工作的代码，并且在spring 4.0.0.RELEASE上失败了NoSuchBeanDefinitionException.RELEASE

I have the below code that worked with spring 3.2 and fails with a "NoSuchBeanDefinitionException" on spring 4.0.0.RELEASE

    
    public interface Cacheable {
    }

    public class TimeUnit implements Cacheable {
    }

    @Component
    public class UserDao<T extends Cacheable> {


        public void performDBOperation() {
            System.out.println("Executing db operation");
        }
    }

    @Component
    public class UserService {
         @Autowired
         private UserDao<TimeUnit> timeUnitUserDao;

         public void someService() {
             timeUnitUserDao.performDBOperation();
         }
    }

当我在UserDao类声明中包含T扩展Cacheable时，由于泛型失败。完整的例外是

It fails due to generics when I include T extends Cacheable in the UserDao class declaration. The complete exception is

NoSuchBeanDefinitionException：找不到依赖关系类型为[spring.generics.UserDao]的符合条件的bean：至少有一个bean符合此选项的autowire候选依赖性依赖关系注释：{@ org.springframework.beans.factory.annotation.Autowired（required = true），@ org.springframework.beans.factory.annotation.Qualifier（value = userdao）}

"NoSuchBeanDefinitionException: No qualifying bean of type [spring.generics.UserDao] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true), @org.springframework.beans.factory.annotation.Qualifier(value=userdao)}"

如果声明只是UserDao& lt&T& gt，它一切正常。

If the declaration is just UserDao &lt T &gt, it all works.

任何意见/输入应该是什么修正？

Any comments/inputs on what should be the fix?

推荐答案

这个问题在春季4.0.1中解决了

This issue was resolved in spring 4.0.1

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