1.Springboot中实现Filter实现的途径

• 实现javax.servlet.Filter接口，注解方式配置Filter
• 实现javax.servlet.Filter接口, 通过FilterRegistrationBean类控制配置
• 通过org.springframework.boot.context.embedded.ServletContextInitializer接口实现类配置

** 2.注解的方式配置Filter**

创建实现Filter接口的实现类AnnoantationFilter

/** * @author gschao
 * @date 2016/11/17 15:19.
 * 注释方式新建Filter 
*/
@WebFilter(filterName = "annoantationFilter" ,urlPatterns = {"/home"})
public class AnnoantationFilter implements Filter{
    private Logger logger = LoggerFactory.getLogger(AnnoantationFilter.class);
    /**
     * 初始化     
     * @param filterConfig
     * @throws ServletException
     */
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        logger.info("####AnnoantationFilter init……"+filterConfig.getFilterName());
    }
    /**
     * @author gschao
     * @date 2016-11-17
     * 执行Filter
     * @param servletRequest
     * @param servletResponse
     * @param filterChain
     * @throws IOException
     * @throws ServletException
     */
    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        logger.info("####AnnoantationFilter doFilter");
        filterChain.doFilter(servletRequest,servletResponse);
    }
    /**
     * @author gschao
     * @date 2016-11-17
     * 销毁
     */
    @Override
    public void destroy() {
        logger.info("####Annoantation destory-------");
    }
}

@WebFilter可以设置的属性

@Target({ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Documentedpublic @interface WebFilter {
    String description() default ""; //描述
    String displayName() default "";//展示名称
    WebInitParam[] initParams() default {};//初始化参数
    String filterName() default "";//过滤器名称
    String smallIcon() default "";
    String largeIcon() default "";
    String[] servletNames() default {};
    String[] value() default {};
    String[] urlPatterns() default {};//设置匹配URL
    DispatcherType[] dispatcherTypes() default {DispatcherType.REQUEST};
    boolean asyncSupported() default false;
}

3. 通过FilterRegistrationBean类配置Filter

适用创建Filter实现类或者使用第三方实现类

创建LogTestFilter 类

/**
 * @author gschao
 * @date 2016/11/17 15:15.
 * 日志文件测试Filter
 */
public class LogTestFilter implements Filter {
    private Logger logger = LoggerFactory.getLogger(LogTestFilter.class);
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        logger.info("filter init:"+filterConfig.getFilterName());
    }
    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        logger.info("doFilter----");
        filterChain.doFilter(servletRequest,servletResponse);//直接转发
    }
    @Override
    public void destroy() {
        logger.info("LoggerFilter destory---");
    }
}

创建配置类FilterConfiguration

/**
 * @author gschao
 * @date 2016/11/17 15:09.
 * 过滤器配置
 *
 */
@Configuration
public class FilterConfiguration {
    /**
     * @author gschao
     * @date 2016-11-17
     * 装饰框架SiteMeshFilter配置
     * @return
     */
    @Bean(name = "configurableSiteMeshFilter")
    public FilterRegistrationBean filterRegistrationBean(){
        FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean();
        ConfigurableSiteMeshFilter configurableSiteMeshFilter = new ConfigurableSiteMeshFilter();//        配置拦截请求
        filterRegistrationBean.addUrlPatterns("/*");//        配置Filter
        filterRegistrationBean.setFilter(configurableSiteMeshFilter);
        return filterRegistrationBean;
    }
    /**
     * 注册Filter
     * @return
     */
    @Bean
    public FilterRegistrationBean logTestFilter(){
        FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean(); 
       LogTestFilter logTestFilter = new LogTestFilter();
        filterRegistrationBean.setFilter(logTestFilter);
        return filterRegistrationBean;
    }

4.ServletContextInitializer接口实现类配置

实现ServletContextInitializer接口
实现onStartup(ServletContext var1)方法
ServletContext 源码

  public interface ServletContext {
    ……
    javax.servlet.FilterRegistration.Dynamic addFilter(String var1, String var2);
    javax.servlet.FilterRegistration.Dynamic addFilter(String var1, Filter var2);
    javax.servlet.FilterRegistration.Dynamic addFilter(String var1, Class<? extends Filter> var2);
    <T extends Filter> T createFilter(Class<T> var1) throws ServletException;
    ……
}

可以通过以上方法进行设置。