如何通过Spring @PostConstruct初始化final变量？

Question

我必须初始化一些最终变量，但这些值需要由 Spring Properties 读取

public class CrawlerClient{
    @Autowired
    @Qualifier("crawlerProperties")
    private Properties crawlerProperties;

    private Integer  final maxTopic;
    public static void main(String[] args) {
        //initialize();
    }
    @PostConstruct
    private void initialize(){
        List<Topic> topics = topicBusiness.getAll();
        List<Blogger> bloggers = bloggerBusiness.getAll();
        List<Clue> clues = clueBusiness.getAll();
        ClueQueue.addAll(clues);
        TopicQueue.addAll(topics);
        BloggerQueue.addAll(bloggers);

    }
..
}

我想初始化“maxTopic”变量，但值在属性中，所以我无法在构造中执行此操作，我该怎么做？我只知道删除“final”键。最后，我是这样做的：

final Integer maxTopic;
    final Integer maxBlogger;
    final Integer maxClue;
    @Autowired
    public CrawlerClient(@Qualifier("crawlerProperties")Properties crawlerProperties){
        this.maxTopic = Integer.parseInt(crawlerProperties.getProperty("MaxTopic"));
        this.maxBlogger = Integer.parseInt(crawlerProperties.getProperty("MaxBlogger"));
        this.maxClue = Integer.parseInt(crawlerProperties.getProperty("MaxClue"));
    }

有人能用更好的方法解决吗？

Answer 1

我相信你可以通过构造函数注入实现你想要的：

@Component
public class CrawlerClient{
    private Properties crawlerProperties;
    private final Integer maxTopic;

    @Autowired
    public CrawlerClient(@Qualifier("crawlerProperties") Properties crawlerProperties,
         @Value("maxTopic") Integer maxTopic){
        this.crawlerProperties = crawlerProperties;
        this.maxTopic = maxTopic;

        List<Topic> topics = topicBusiness.getAll();
        List<Blogger> bloggers = bloggerBusiness.getAll();
        List<Clue> clues = clueBusiness.getAll();
        ClueQueue.addAll(clues);
        TopicQueue.addAll(topics);
        BloggerQueue.addAll(bloggers);
    }
..
}