SpringBoot（3）自定义Filter

SpringBoot自动添加了OrderedCharacterEncodingFilter和HiddenHttpMethodFilter，当然我们可以自定 
义Filter。

自定义Filter需要两个步骤：

1. 实现Filter【javax.servlet.Filter】接口，实现Filter方法
2. 添加 @Configuration 注解，将自定义Filter加入过滤链

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【过滤打印请求URL】实例代码如下：

package xatu.zsl.Filter;

import org.apache.catalina.filters.RemoteIpFilter;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

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

/**
 * Created by zsl on 2017/9/3.
 */
@Configuration
public class ConfigurationFilter {
    @Bean
    public RemoteIpFilter remoteIpFilter() {
        return new RemoteIpFilter();
    }

    @Bean
    public FilterRegistrationBean testFilterRegistration() {
        FilterRegistrationBean registration = new FilterRegistrationBean();
        registration.setFilter(new MyFilter());//添加过滤器
        registration.addUrlPatterns("/*");//设置过滤路径，/*所有路径
        registration.addInitParameter("name", "alue");//添加默认参数
        registration.setName("MyFilter");//设置优先级
        registration.setOrder(1);//设置优先级
        return registration;
    }

    public class MyFilter implements Filter {
        @Override
        public void destroy() {
        }

        @Override
        public void doFilter(ServletRequest srequest, ServletResponse sresponse, FilterChain
                filterChain)
                throws IOException, ServletException {
            HttpServletRequest request = (HttpServletRequest) srequest;
            //打印请求Url
            System.out.println("this is MyFilter,url :" + request.getRequestURI());
            filterChain.doFilter(srequest, sresponse);
        }

        @Override
        public void init(FilterConfig arg0) throws ServletException {
        }
    }
}