@autowired和@Resource

前言

关于注解和xml配置的官方回答

Are annotations better than XML for configuring Spring?The introduction of annotation-based configurations raised the question of whether this approach is 'better' than XML. The short answer is it depends. The long answer is that each approach has its pros and cons, and usually it is up to the developer to decide which strategy suits them better. Due to the way they are defined, annotations provide a lot of context in their declaration, leading to shorter and more concise configuration. However, XML excels at wiring up components without touching their source code or recompiling them. Some developers prefer having the wiring close to the source while others argue that annotated classes are no longer POJOs and, furthermore, that the configuration becomes decentralized and harder to control.No matter the choice, Spring can accommodate both styles and even mix them together. It’s worth pointing out that through its JavaConfig option, Spring allows annotations to be used in a non-invasive way, without touching the target components source code and that in terms of tooling, all configuration styles are supported by the Spring Tool Suite.

两种注解的说明

@autowired

简介

autowired是spring官方提供的一种装配方式。

使用方法

1.使用在方法上:

public class SimpleMovieLister {    private MovieFinder movieFinder;    @Autowired    public void setMovieFinder(MovieFinder movieFinder) {        this.movieFinder = movieFinder;    }    // ...}

2.使用在字段上

  @Autowired    private MovieCatalog movieCatalog;

说明

autowired主要是用bytype的方式注入。

@Resource

简介

@resource是java自带的一种装配方式。

使用方法

与@autowired相似
1.指定name属性

 @Resource(name="myMovieFinder")    public void setMovieFinder(MovieFinder movieFinder) {        this.movieFinder = movieFinder;    }

2.默认[使用默认提供名称]

 @Resource    public void setMovieFinder(MovieFinder movieFinder) {        this.movieFinder = movieFinder;    }

说明

@Resource默认按名称进行装配，名称可以通过name属性进行指定，如果没有指定name属性，当注解写在字段上时，默认取字段名进行名称查找。

总结

两种方式的功能大致相同，默认推荐使用@Resource方式，这是j2ee生的方式。能降低和spring的耦合度。

更多具体详情请参见官方：http://spring.io