[英]How to Autowire a class at runtime in a method
Is it possible to Autowire fields in a dynamic class? 是否可以自动连接动态类中的字段? I am getting a class name from the database and I want to autowire this class 我从数据库中获取一个班级名称,我想自动连接该班级
Short Answer 简短答案
That's not possible. 那不可能 Spring needs to know what Beans there are for injecting them. Spring需要知道有哪些Bean可以注入它们。
Long Answer 长答案
You could @Autowire
every possible bean into a class and then cache them in a Map, where the Class represents the key, and the Object the value. 您可以@Autowire
所有可能的bean放入一个类,然后将它们缓存在Map中,其中Class代表键,Object则值。 See below simplified example: 请参见下面的简化示例:
public class MyClass{
private final Map<Class<?>, Object> cache = new HashMap<>();
@Autowired
public MyClass(Service1 s1, Service2 s2){
// registering the beans
cache.put(Service1.class, s1);
cache.put(Service2.class, s2);
}
public <T> T getService(String className) throws ClassNotFoundException{
// getting the bean
Class<?> clazz = Class.forName(className);
return (T) cache.get(clazz);
}
}
不确定这是一个好主意,但是您可以注入这里提到的类: 将bean注入Spring托管上下文之外的类中
You can try this: 您可以尝试以下方法:
import javax.annotation.PostConstruct;
@Component
public class ApplicationContextAccessor {
private static ApplicationContextAccessor instance;
@Autowired
private ApplicationContext applicationContext;
public static T getBean(Class clazz) {
return instance.applicationContext.getBean(clazz);
}
@PostConstruct
private void registerInstance() {
instance = this;
}
} }
Read this post : https://www.helicaltech.com/uses-of-springs-applicationcontext-while-using-reflection/ 阅读这篇文章: https : //www.helicaltech.com/uses-of-springs-applicationcontext-while-using-reflection/
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