@Value不注入屬性，保持爲null

我有一個servlet正在運行，我正在嘗試將一個屬性值注入到Filter中。@Value不注入屬性，保持爲null

我相信appConfig文件正在被加載（當我改變文件名時，我得到一個FileNotFound異常）。屬性文件的計數相同。

似乎我嘗試注入屬性的類在某種程度上被Spring忽略了。這是一個過濾器（見下文）。我已經通過在註釋本身中添加屬性值來進行試驗。（@Value（「$ {filter.weburl： '一些'}」。）但是，字符串WEBURL保持爲空

誰能幫助我弄清楚是怎麼回事

package example.servlet.filters; 

import org.slf4j.Logger; 
import org.slf4j.LoggerFactory; 
import org.springframework.beans.factory.annotation.Value; 
import org.springframework.stereotype.Component; 

import javax.servlet.*; 
import javax.servlet.http.Cookie; 
import javax.servlet.http.HttpServletRequest; 
import javax.servlet.http.HttpServletResponse; 
import java.io.IOException; 


@Component 
public class AuthenticationFilter implements Filter{ 

    private ServletContext context; 
    private final Logger LOGGER = LoggerFactory.getLogger(AuthenticationFilter.class); 
    @Value("${filter.weburl:'some'}") 
    private String webURL; 

    @Override 
    public void init(FilterConfig filterConfig) throws ServletException { 
     this.context = filterConfig.getServletContext(); 
     this.context.log("AuthenticationFilter initialized"); 

    } 

    @Override 
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException { 
     HttpServletRequest request = (HttpServletRequest) servletRequest; 
     Cookie[] cookies = request.getCookies(); 
     if(cookies != null) { 
      for (Cookie cookie : cookies) { 
       System.out.println(cookie.getName() + " " + cookie.getValue() + "\n"); 
      } 
     } else { 
      ((HttpServletResponse)servletResponse).sendRedirect(webURL + "/inloggen"); 
     } 
     filterChain.doFilter(servletRequest, servletResponse); 
    } 

    @Override 
    public void destroy() { 

    } 
}

我？ AppConfig的文件：

package example; 

import org.springframework.context.annotation.Bean; 
import org.springframework.context.annotation.ComponentScan; 
import org.springframework.context.annotation.Configuration; 
import org.springframework.context.annotation.PropertySource; 
import org.springframework.context.support.PropertySourcesPlaceholderConfigurer; 

@Configuration 
@ComponentScan("example") 
@PropertySource("WEB-INF/service.properties") 
public class AppConfig { 
    @Bean 
    public static PropertySourcesPlaceholderConfigurer getPropertySourcesPlaceholderConfigurer() { 
     return new PropertySourcesPlaceholderConfigurer(); 
    } 

    @Bean 
    public FilterRegistrationBean authenticationFilterRegistrationBean() { 
     FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean(); 
     filterRegistrationBean.setFilter(getAuthenticationFilter()); 
     filterRegistrationBean.addUrlPatterns("/*"); 
     filterRegistrationBean.setName("authenticationFilter"); 
     filterRegistrationBean.setOrder(1); 
     return null; 
    } 

    @Bean(name="authenticationFilter") 
    public AuthenticationFilter getAuthenticationFilter() { 
     return new AuthenticationFilter(); 
    } 
}

來源

2017-02-27 Robert van der Spek

你的過濾器其實也是一個Spring bean？基本上，如果該字段無法解析，則該字段不能爲空，它將回退到您提供的默認值。由於事實並非如此，我懷疑你使用的過濾器的實例是Spring所知的一個實例。 –

您是否嘗試過設置應該由@Value填充到公共的字段？ –

您必須配置類以下

@Bean 
    public static PropertySourcesPlaceholderConfigurer propertySourcesPlaceholderConfigurer() { 
     return new PropertySourcesPlaceholderConfigurer(); 
    }

要使用web.xm配置過濾器。 l如果您在註冊將被註冊的所有請求，如果使用FilterRegistrationBean，你可以自定義過濾器適用於URL路徑的應用程序上下文的過濾器做到這一點

<filter> 
    <filter-name>authenticationFilter</filter-name> 
    <filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class> 
</filter> 

<filter-mapping> 
    <filter-name>authenticationFilter</filter-name> 
    <url-pattern>/*</url-pattern> 
</filter-mapping>

來源

2017-02-27 11:01:23 mhshimul

我應該添加這個到我的問題，但它已經在那裏:-)。我編輯了我的問題來澄清這一點。 –

你怎麼註冊你的過濾器？你可以分享該代碼嗎？ – mhshimul

看到我的答案在這裏http://stackoverflow.com/questions/42176625/spring-boot-1-5-1-inside-registered-filter-can-not-access-spring-context-valu – mhshimul

。你似乎有兩個，它可能會導致各種問題。此外，您的過濾器使用@Component進行註釋，並且您正在創建過濾器作爲配置類中的bean。

這是你如何組織你的代碼，使其工作：

// No @Component annotation keeps this class pure as you're using your configuration class to create beans 
public class AuthenticationFilter implements Filter{ 

    private ServletContext context; 
    private final Logger LOGGER = LoggerFactory.getLogger(AuthenticationFilter.class); 
    private String webURL; 

    public AuthenticationFilter(String webURL) { 
     this.webURL = webURL; 
    } 

    // rest of filter 
}

配置類：

@Configuration 
@ComponentScan("example") //if you have other components to scan, otherwise not required 
@PropertySource("WEB-INF/service.properties") 
public class AppConfig { 

    @Value("${filter.weburl:some}") 
    String webURL; 

    @Bean 
    public static PropertySourcesPlaceholderConfigurer getPropertySourcesPlaceholderConfigurer() { 
     return new PropertySourcesPlaceholderConfigurer(); 
    } 

    @Bean 
    public FilterRegistrationBean authenticationFilterRegistrationBean() { 
     FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean(); 
     filterRegistrationBean.setFilter(new AuthenticationFilter(this.webURL)); 
     filterRegistrationBean.addUrlPatterns("/*"); 
     filterRegistrationBean.setName("authenticationFilter"); 
     filterRegistrationBean.setOrder(1); 
     return filterRegistrationBean; 
    } 
}

來源

2017-02-27 13:43:57 Strelok

@Value不注入屬性，保持爲null

回答

相關問題