IoC¶
基于注解配置¶
@Autowired¶
@Autowired 注解可以用于构造函数、setter、任意方法和成员变量来注入 bean.
public class MovieRecommender {
private final CustomerPreferenceDao customerPreferenceDao;
private MovieFinder movieFinder;
private MovieCatalog movieCatalog;
private PreferenceDao preferenceDao;
/**
* It can be ignored when there is only one constructor.
* At least one of constructors must be annotated
* if more than one constructors are available and there is no primary/default one.
*/
@Autowired
public MovieRecommender(CustomerPreferenceDao customerPreferenceDao) {
this.customerPreferenceDao = customerPreferenceDao;
}
@Autowired
public void setMovieFinder(MovieFinder movieFinder) {
this.movieFinder = movieFinder;
}
@Autowired
public void prepare(MovieCatalog movieCatalog, PreferenceDao preferenceDao) {
this.movieCatalog = movieCatalog;
this.preferenceDao = preferenceDao;
}
// ...
}
也可以通过数组和集合类型注入同类型的多个 beans.
public class MovieRecommender {
@Autowired
private MovieFinder[] movieFinders;
private Set<MovieCatalog> movieCatalogs;
// key is name of the bean
private Map<String, MovieCreator> movieCreators;
@Autowired
public void setMovieCatalogs(Set<MovieCatalog> movieCatalogs) {
this.movieCatalogs = movieCatalogs;
}
@Autowired
public void setMovieCreators(Map<String, MovieCreator> movieCreators) {
this.movieCreators = movieCreators;
}
// ...
}
@Resource¶
@Resource 根据名称注入 bean，未指定或找不到再根据类型匹配。
public class SimpleMovieLister {
private MovieFinder movieFinder;
@Resource(name="myMovieFinder")
public void setMovieFinder(MovieFinder movieFinder) {
this.movieFinder = movieFinder;
}
}