Spring boot 学习八 Springboot的filter

一：  传统的javaEE增加Filter是在web.xml中配置，如以下代码：

<filter>
   <filter-name>TestFilter</filter-name>
    <filter-class>com.cppba.filter.TestFilter</filter-class>
</filter>
<filter-mapping>
  <filter-name>TestFilter</filter-name>
  <url-pattern>/*</url-pattern>
  <init-param>
    <param-name>paramName</param-name>
    <param-value>paramValue</param-value>
  </init-param>
</filter-mapping>

二： springBoot中的老方法：

　　2.1 創建自定义filter

package com.cppba.filter;

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

public class TestFilter implements Filter {
  @Override
  public void init(FilterConfig filterConfig) throws ServletException {
  }

  @Override
  public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain)
      throws IOException, ServletException {
    System.out.println("TestFilter");
  }

  @Override
  public void destroy() {
  }
}

　　2.2  配置类中增加增加一个@bean

@Bean
 public FilterRegistrationBean testFilterRegistration() {

   FilterRegistrationBean registration = new FilterRegistrationBean();
   registration.setFilter(new TestFilter());
   registration.addUrlPatterns("/*");
   registration.addInitParameter("paramName", "paramValue");
   registration.setName("testFilter");
   registration.setOrder(1);
   return registration;
 }

//  如下，可以配置多个filter， 每个filter对应一个FilterRegistrationBean ，对filter进行排序

 @Bean
    public FilterRegistrationBean otherFilterRegistration() {
        FilterRegistrationBean registration = new FilterRegistrationBean();
        registration.setFilter(otherFilter());
        registration.addUrlPatterns("/*");
        registration.addInitParameter("paramName", "paramValue");
        registration.setName("filterDemo4");
        registration.setOrder(2);
        return registration;
    }

三 springBoot中的老方法：

　　3.1 自定义filter

@Order(1)        //fitler顺序
//重点
@WebFilter(filterName = "testFilter1", urlPatterns = "/*")
public class TestFilterFirst implements Filter {
  @Override
  public void init(FilterConfig filterConfig) throws ServletException {
  }

  @Override
  public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain)
      throws IOException, ServletException {
    System.out.println("TestFilter1");
    filterChain.doFilter(servletRequest,servletResponse);
  }

  @Override
  public void destroy() {
  }
}

我们在spring-boot的入口处加上如下注解@ServletComponentScan：

@SpringBootApplication(scanBasePackages = "com.cppba")
//重点
@ServletComponentScan
public class Application {
  public static void main(String[] args) throws UnknownHostException {
    SpringApplication app = new SpringApplication(Application.class);
    Environment environment = app.run(args).getEnvironment();
  }
}

 四： WebStatFilter用于采集web-jdbc关联监控的数据