SpringBoot - 整合Filter的两种方式

整合Filter其实和整合Servlet是一样的，都是这两种方式

前面的构建过程就不截图

1.通过注解

 编写一个Servlet作为入口

@WebServlet(name="firstServlet",value="/first")
public class FirstServlet extends HttpServlet{
  private static final long serialVersionUID = 1L;
  @Override
  protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    System.out.println("doget");
  }
}

编写Filter类

package cn.bl.filter;

import java.io.IOException;

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;

//@WebFilter(filterName="filterTest",urlPatterns= {"",""})
@WebFilter(filterName="filterTest1",urlPatterns="/*")
public class FilterTest implements Filter{
  @Override
  public void init(FilterConfig filterConfig) throws ServletException {
  }
  @Override
  public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
      throws IOException, ServletException {
    System.out.println("来了1");
    chain.doFilter(request, response);
    System.out.println("走了1");
  }
  @Override
  public void destroy() {
  }
}

最后是启动类

package cn.bl;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.web.servlet.ServletComponentScan;

@SpringBootApplication
@ServletComponentScan
public class App {
  public static void main(String[] args) {
    SpringApplication.run(App.class, args);
  }
}

同样，也是执行这个main，然后浏览器访问：​​http://localhost:8080/first​​

2.通过方法完成Filter组件的注册

Servlet还用原来的

Filter如下

package cn.bl.filter;

import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;

public class FilterTest2 implements Filter{
  @Override
  public void init(FilterConfig filterConfig) throws ServletException {
  }
  @Override
  public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
      throws IOException, ServletException {
    System.out.println("来了2");
    chain.doFilter(request, response);
    System.out.println("走了2");
  }
  @Override
  public void destroy() {
  }
}

启动类

package cn.bl;

import javax.servlet.http.HttpServlet;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.boot.web.servlet.ServletRegistrationBean;
import org.springframework.context.annotation.Bean;

import cn.bl.filter.FilterTest2;
import cn.bl.servlet.FirstServlet;

@SpringBootApplication
public class App2 {
  public static void main(String[] args) {
    SpringApplication.run(App2.class, args);
  }
  @Bean
  public FilterRegistrationBean<FilterTest2> getFilterRegistrationBean(){
    FilterRegistrationBean<FilterTest2> bean = new FilterRegistrationBean<>(new FilterTest2());
    bean.addUrlPatterns("/*");
    return bean;
  }
  @Bean
  public ServletRegistrationBean<HttpServlet>getServletRegistrationBean(){
    ServletRegistrationBean<HttpServlet>bean = new ServletRegistrationBean<>(new FirstServlet());
    bean.addUrlMappings("/second");
    return bean;
  }
}