@Autowired靜態注入導致的sonar壞味道：Write to static field ...Utils.staticService from instance method ...Utils.init()

sonar掃描出現了一個嚴重的壞味道Write to static field ...Utils.staticService from instance method ...Utils.init()

 

意思就是：當一個靜態變量直接賦值給靜態變量，在多線程調用的情況下，容易出現問題。

 

解決方法就是使用兩個set方法（一個靜態set方法，一個動態set方法），代替動態變量直接賦值給靜態變量的寫法。

 

修改前的代碼：

@Component
public class RuleDocTypeUtils {

     private static final Logger LOGGER =  LoggerFactory.getLogger(RuleDocTypeUtils.class);
     
     private static DocTypeRuleServiceImpl staticService = new  DocTypeRuleServiceImpl();
    
     @Autowired
     private DocTypeRuleServiceImpl dynamicService;
     
     @PostConstruct
     public void init() {
           staticService = dynamicService;
     }

     ...

}

可以看到，在init()方法中動態服務對象直接賦值給靜態服務對象，正是這一行出了問題，如果改為使用set注入靜態服務對象的方式，一樣有這個問題

 

修改后的代碼：

@Component
public class RuleDocTypeUtils {

     private static final Logger LOGGER =  LoggerFactory.getLogger(RuleDocTypeUtils.class);
     
     private static DocTypeRuleServiceImpl staticService = new  DocTypeRuleServiceImpl();
    
     @Autowired
     private DocTypeRuleServiceImpl dynamicService;
     
     @PostConstruct
     public void init() {
           setService(dynamicService);
     }

     private void setService(DocTypeRuleServiceImpl  dynamicService) {
           setStaticService(dynamicService);
     }

     private synchronized static void  setStaticService(DocTypeRuleServiceImpl dynamicService) {
           RuleDocTypeUtils.staticService = dynamicService;
     }

     ...

}

 

參考：

    1.Write to static field from instance method ：  https://stackoverflow.com/questions/24703755/write-to-static-field-from-instance-method?r=SearchResults

    2.FindBugs error: Write to static field from instance method ：  https://stackoverflow.com/questions/21136302/findbugs-error-write-to-static-field-from-instance-method#

    3.FindBugs error: Write to static field from instance method ：  http://www.hackerav.com/?post=61820