Spring-Boot 整合Servlet和Filter

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整合Servlet

传统方式配置

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<servlet>
<servlet-name>FirstServlet</servlet-name>
<servlet-class>com.caicai.springbootservlet.filter.FirstFilter</servlet-class>
</servlet>

<servlet-mapping>
<servlet-name>FirstServlet</servlet-name>
<url-pattern>/first</url-pattern>
</servlet-mapping>

通过注解扫描注册Servlet

使用@WebServlet注解并在启动类上使用@ServletComponentScan注解

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@WebServlet(name = "FirstServlet",urlPatterns = "/first")
public class FirstServlet extends HttpServlet{
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        System.out.println("FirstServlet.....");
    }
}
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@SpringBootApplication
@ServletComponentScan //在SpringBoot启动时会扫描@WebServlet注解 并将该类实例化
public class Application {

	public static void main(String[] args) {
		SpringApplication.run(Application.class, args);
	}

}

通过方法完成Servlet组件的注册

通过使用@Bean注解的形式注册组件

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public class SecondServlet extends HttpServlet{
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        System.out.println("SecondServlet.....");
    }
}
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@SpringBootApplication
public class App2 {
    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }

    @Bean
    public ServletRegistrationBean getServletRegistrationBean() {
        ServletRegistrationBean bean = new ServletRegistrationBean(new SecondServlet());
        bean.addUrlMappings("/second");//添加url路径
        return bean;
    }
}

整合Filter

传统方式配置

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<filter>
<filter-name>FirstFilter</filter-name>
<filter-class>com.caicai.springbootservlet.filter.FirstFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>FirstFilter</filter-name>
<url-pattern>/filter1</url-pattern>
</filter-mapping>

通过注解扫描注册Servlet

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package com.caicai.springbootservlet.filter;

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

/**
 * @author liu
 * @title: FirstFilter
 * @projectName 02-spring-boot-servlet
 * @description: TODO
 * @date 2019/3/2718:19
 */
//@WebFilter(filterName = "",urlPatterns ={"*.do","*.jsp"})
@WebFilter(filterName = "FirstFilter",urlPatterns ="/filter1")
public class FirstFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        System.out.println("init.......");
    }

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

    }

    @Override
    public void destroy() {
        System.out.println("destroy.......");

    }
}

启动类:

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package com.caicai.springbootservlet;

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

@SpringBootApplication
@ServletComponentScan //在SpringBoot启动时会扫描@WebServlet注解 并将该类实例化
public class App3 {
	public static void main(String[] args) {
		SpringApplication.run(App3.class, args);
	}

}

通过方法完成Filter的注册

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package com.caicai.springbootservlet.filter;

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

/**
 * @author liu
 * @title: SecondFilter
 * @projectName 02-spring-boot-servlet
 * @description: TODO
 * @date 2019/3/2718:19
 */

public class SecondFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        System.out.println("init.......");
    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        System.out.println("进入filter2.......");
        filterChain.doFilter(servletRequest,servletResponse);
        System.out.println("离开filter2.......");

    }

    @Override
    public void destroy() {
        System.out.println("destroy.......");

    }
}

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package com.caicai.springbootservlet;

import com.caicai.springbootservlet.filter.SecondFilter;
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;

@SpringBootApplication
public class App4 {
	public static void main(String[] args) {
		SpringApplication.run(App4.class, args);
	}

	@Bean
	public FilterRegistrationBean filterRegistrationBean(){
        FilterRegistrationBean bean = new FilterRegistrationBean(new SecondFilter()) ;
        bean.addUrlPatterns("/filter2");
        return bean;
    }

}