我建立一個全域性攔截器，此攔截器主要用於攔截APP使用者登入和請求API時候，必須加密，我把它命名為SecurityFilter，它繼承了Filter，web應用啟動的順序是：listener->filter->servlet，

而因為專案應用了SpringBoot，所以我們專案啟動時，先初始化listener，因此註解的bean會被初始化和注入；然後再來就filter的初始化，再接著才到我們的dispathServlet的初始化，因此，當我們需要在filter裡注入一個註解的bean時，就會注入失敗，因為filter初始化時，註解的bean還沒初始化，沒法注入。

那麼，解決方法如下：

@Bean
public FilterRegistrationBean securityFilterRegistration() {
    	FilterRegistrationBean registration = new FilterRegistrationBean();		
	DelegatingFilterProxy httpBasicFilter = new DelegatingFilterProxy();
	registration.setFilter(httpBasicFilter);
	Map<String,String> m = new HashMap<String,String>();
	m.put("targetBeanName","securityFilter");
	m.put("targetFilterLifecycle","true");
	registration.setInitParameters(m);		   
	registration.addUrlPatterns("/appapi/*");

	registration.setOrder(2);
	return registration;
}
 

這樣你就可以在securityFilter 裡面新增@Autowired下的bean了。

@Autowired
private PermissionUserService userService;

以上事項方式會全域性過濾，此過濾不起作用適合於全域性過濾(/*)；

registration.addUrlPatterns("/appapi/*");

建議使用如下方式

@Bean
public FilterRegistrationBean securityFilterRegistration() {
        FilterRegistrationBean registrationBean = new FilterRegistrationBean();
        registrationBean.setFilter(securityFilterBean());
        registrationBean.addUrlPatterns("/appapi/*");
        registrationBean.setName("securityFilter");
        registrationBean.setOrder(2);
        return registrationBean;
    }
	
@Bean
public Filter securityFilterBean() {
 return new SecurityFilter();
}
 

參考文章：

https://blog.csdn.net/xiaoyi52/article/details/76686001

https://blog.csdn.net/cutterwolf/article/details/77849158

https://blog.csdn.net/u013076044/article/details/72903130

https://blog.csdn.net/angel708884645/article/details/51148865

如何在servlet取得spring beans (autowired)

https://blog.csdn.net/axzywan/article/details/8056892