@WebFilter注解过滤器

@WebFilter注解过滤器

@WebFilter加在过滤器的注解上使用

import lombok.extern.slf4j.Slf4j;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.annotation.WebFilter;
import java.io.IOException;

@WebFilter(urlPatterns = "/*")
@Slf4j
public class WebFilterTest implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        log.info("WebFilterTest --- init");
    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        log.info("WebFilterTest --- doFilter");
        filterChain.doFilter(servletRequest,servletResponse);
    }

    @Override
    public void destroy() {
        log.info("WebFilterTest --- destroy");
    }
}

@WebFilter源码:

@Target({ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface WebFilter {
    String description() default "";
    /**Filter显示名*/
    String displayName() default "";
    /**配置参数*/
    WebInitParam[] initParams() default {};
    /**Filter名称*/
    String filterName() default "";

    String smallIcon() default "";

    String largeIcon() default "";
    /**指定对哪些Servlet进行过滤*/
    String[] servletNames() default {};
    /**指定拦截的路径*/
    String[] value() default {};
    /**指定拦截的路径*/
    String[] urlPatterns() default {};
    /**指定Filter对哪种方式的请求进行过滤*/
    DispatcherType[] dispatcherTypes() default {DispatcherType.REQUEST};
    /**指定Filter是否支持异步模式*/
    boolean asyncSupported() default false;
}

在springBoot的启动类中加入注解:

import org.springframework.boot.web.servlet.ServletComponentScan;

@ServletComponentScan

多个@WebFilter注解的过滤器可以配合@Order()注解实现执行过滤的顺序

import org.springframework.core.annotation.Order;

@WebFilter(urlPatterns = "/*")
@Slf4j
@Order(1)
public class WebFilterTest implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        log.info("WebFilterTest --- init");
    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        log.info("WebFilterTest --- doFilter");
        filterChain.doFilter(servletRequest,servletResponse);
    }

    @Override
    public void destroy() {
        log.info("WebFilterTest --- destroy");
    }
}

@WebFilter(urlPatterns = "/*")
@Slf4j
@Order(2)
public class WebFilterTest2 implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        log.info("2---WebFilterTest2 --- init");
    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        log.info("2 --- WebFilterTest2 --- doFilter");
        filterChain.doFilter(servletRequest,servletResponse);
    }

    @Override
    public void destroy() {
        log.info("WebFilterTest2 --- destroy");
    }
}

执行结果

WebFilterTest --- doFilter
2 --- WebFilterTest2 --- doFilter

不使用注解的方式使用过滤器

创建过滤器类

public class WebFilterTest implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        log.info("WebFilterTest --- init");
    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        log.info("WebFilterTest --- doFilter");
        filterChain.doFilter(servletRequest,servletResponse);
    }

    @Override
    public void destroy() {
        log.info("WebFilterTest --- destroy");
    }
}

注册过滤器

@Configuration
public class FilterConfig {

    @Bean
    public WebFilterTest webFilterTest(){
        return new WebFilterTest();
    }

    @Bean
    public FilterRegistrationBean filterRegist(){
        FilterRegistrationBean frBean = new FilterRegistrationBean();
        frBean.setFilter(webFilterTest());
        frBean.setOrder(1);
        frBean.addUrlPatterns("/*");
        return  frBean;
    }
}

多个过滤器注册

再添加一个过滤器:

@Slf4j
public class WebFilterTest2 implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        log.info("2---WebFilterTest2 --- init");
    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        log.info("2 --- WebFilterTest2 --- doFilter");
        filterChain.doFilter(servletRequest,servletResponse);
    }

    @Override
    public void destroy() {
        log.info("WebFilterTest2 --- destroy");
    }
}

修改配置类:

@Configuration
public class FilterConfig {

    @Bean
    public WebFilterTest webFilterTest(){
        return new WebFilterTest();
    }
     @Bean
    public WebFilterTest2 webFilterTest2(){
        return new WebFilterTest2();
    }

    @Bean
    public FilterRegistrationBean filterRegist(){
        FilterRegistrationBean frBean = new FilterRegistrationBean();
        frBean.setFilter(webFilterTest());
        frBean.setOrder(1);
        frBean.addUrlPatterns("/*");
        return  frBean;
    }
    @Bean
    public FilterRegistrationBean filterRegist2(){
        FilterRegistrationBean frBean = new FilterRegistrationBean();
        frBean.setFilter(webFilterTest2());
        frBean.setOrder(2);
        frBean.addUrlPatterns("/*");
        return  frBean;
    }
}

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