findbugs writes to a static field

錯誤提示：This instance method writes to a static field. This is tricky to get correct
原代碼：

 

@Component
public class SpringContextUtil implements ApplicationContextAware {
    private static ApplicationContext applicationContext = null;

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        this.applicationContext = applicationContext;
    }

    public static ApplicationContext getApplicationContext() {
        return applicationContext;
    }

    public static Object getBean(String beanName) {
        return applicationContext.getBean(beanName);
    }

    public static Object getBean(Class clazz) {
        return applicationContext.getBean(clazz);
    }
}

改進後的代碼：

@Component
public class SpringContextUtil implements ApplicationContextAware {

    private SpringContextUtil(){}

    private static ApplicationContext applicationContext = null;

    private synchronized static void setSyncApplicationContext(ApplicationContext applicationContext) {
        SpringContextUtil.applicationContext = applicationContext;
    }

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        setSyncApplicationContext(applicationContext);
    }

    public static ApplicationContext getApplicationContext() {
        return applicationContext;
    }

    public static Object getBean(String beanName) {
        return applicationContext.getBean(beanName);
    }

    public static Object getBean(Class clazz) {
        return applicationContext.getBean(clazz);
    }

}

 

提示這個原因是，原來的寫法不識線程安全的。所以通過增加synchronized，進行解決。

As an aside, in my opinion Google’s CodePro Analytix plugin is a much faster and more comprehensive tool than FindBugs.

Related:

• Synchronized vs. Volatile in Java

• Synchronized Getters and Setters

 

參考：

https://stackoverflow.com/questions/13388829/write-to-static-field-is-findbugs-wrong-in-this-case