SpringBoot整合JavaWeb

一、SpringBoot整合Servlet的两种方式

1.通过注解扫描完成Servlet组件的注册

编写Servlet

package com.example.demo.servlet;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 *SpringBoot整合Servlet方式一
 *
 *<servlet>
 *    <servlet-name>FirstServlet</servlet-name>
 *    <servlet-class>com.bjsxt.servlet.FirstServlet</servlet-class>
 *</servlet>
 *
 *<servlet-mapping>
 * <servlet-name>FirstServlet</servlet-name>
 * <url-pattern>/first</url-pattern>
 *</servlet-mapping>
 *
 */

@WebServlet(name="FirstServlet",urlPatterns="/first")
public class FirstServlet extends HttpServlet {

    /**
     * 
     */
    private static final long serialVersionUID = 8500147337364528371L;

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        super.doGet(req, resp);
        System.out.println("FirstServlet...");
    }
}

编写启动器类

package com.example.demo;

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，并将该类实例化
public class SpringbootWebApplication {

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

}

2.通过方法完成Servlet组件的注册

编写Servlet

package com.example.demo.servlet;

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 *SpringBoot整合Servlet方式二
 *
 */

public class SecondServlet extends HttpServlet {

    /**
     * 
     */
    private static final long serialVersionUID = -7076398985231616781L;

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        System.out.println("SecondServlet...");
    }
    
}

编写启动器类

package com.example.demo;

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

import com.example.demo.servlet.SecondServlet;

/**
 * SpringBoot整合Servlet方式二
 *
 *
 */
@SpringBootApplication
public class App2 {

    public static void main(String[] args) {
        SpringApplication.run(App2.class, args);
    }
    
    @Bean
    public ServletRegistrationBean getServletRegistrationBean(){
        ServletRegistrationBean bean = new ServletRegistrationBean(new SecondServlet());
        bean.addUrlMappings("/second");
        return bean;
    }
}

二、SpringBoot整合Filter的两种方式

1.通过注解扫描完成Filter组件的注册

编写Filter

/**
 *SpringBoot整合Filter 方式一
 *<filter>
 *    <filter-name>FirstFilter</filter-name>
 *    <filter-class>com.bjsxt.filter.FirstFilter</filter-class>
 *</filter>
 *<filter-mapping>
 *    <filter-name>FirstFilter</filter-name>
 *    <url-pattern>/first</url-pattern>
 *</filter-mapping>
 */
//@WebFilter(filterName="FirstFilter",urlPatterns={"*.do","*.jsp"})
@WebFilter(filterName="FirstFilter",urlPatterns="/first")
public class FirstFilter implements Filter {

    @Override
    public void destroy() {
        // TODO Auto-generated method stub

    }
    @Override
    public void doFilter(ServletRequest arg0, ServletResponse arg1, FilterChain arg2)
            throws IOException, ServletException {
        System.out.println("进入Filter");
        arg2.doFilter(arg0, arg1);
        System.out.println("离开Filter");
    }

    @Override
    public void init(FilterConfig arg0) throws ServletException {
        // TODO Auto-generated method stub
    }
}

编写启动类

/**
 *SpringBoot整合Filter 方式一
 *
 */
@SpringBootApplication
@ServletComponentScan
public class App3 {

    public static void main(String[] args) {
        SpringApplication.run(App3.class, args);

    }

}

2.通过方法完成Filter组件的注册

编写Filter

/**
 * 
 *SpringBoot整合Filter 方式二
 *
 */
public class SecondFilter implements Filter {
    @Override
    public void destroy() {
        // TODO Auto-generated method stub
    }
    @Override
    public void doFilter(ServletRequest arg0, ServletResponse arg1, FilterChain arg2)
            throws IOException, ServletException {
        System.out.println("进入SecondFilter");
        arg2.doFilter(arg0, arg1);
        System.out.println("离开SecondFilter");
    }

    @Override
    public void init(FilterConfig arg0) throws ServletException {
        // TODO Auto-generated method stub
    }
}

编写启动器类

/**
 * SpringBoot整合Filter方式二
 *
 *
 */
@SpringBootApplication
public class App4 {

    public static void main(String[] args) {
        SpringApplication.run(App4.class, args);
    }/**
     * 注册Filter
     */
    @Bean
    public FilterRegistrationBean getFilterRegistrationBean(){
        FilterRegistrationBean bean = new FilterRegistrationBean(new SecondFilter());
        //bean.addUrlPatterns(new String[]{"*.do","*.jsp"});
        bean.addUrlPatterns("/second");
        return bean;
    }
}

三、SpringBoot整合Listener的两种方式

1.通过注解扫描完成Listener的注册

编写Listener

/**
 * springBoot整合Listener
 *
 *<listener>
 *    <listener-class>com.bjsxt.listener.FirstListener</listener-class>
 *</listener>
 */
@WebListener
public class FirstListener implements ServletContextListener {

    @Override
    public void contextDestroyed(ServletContextEvent arg0) {
        // TODO Auto-generated method stub

    }

    @Override
    public void contextInitialized(ServletContextEvent arg0) {
        System.out.println("Listener...init......");

    }

}

编写启动器

/**
 * springBoot整合Listener方式一
 *
 *
 */
@SpringBootApplication
@ServletComponentScan
public class App5 {

    public static void main(String[] args) {
        SpringApplication.run(App5.class, args);
    }

}

2.  通过方法完成Listener组件注册

编写Listener

/**
 * springBoot整合Listener方式二。
 *
 *
 */
public class SecondListener implements ServletContextListener {

    @Override
    public void contextDestroyed(ServletContextEvent arg0) {
        // TODO Auto-generated method stub
    }

    @Override
    public void contextInitialized(ServletContextEvent arg0) {
        System.out.println("SecondListener..init.....");
    }

}

编写启动器类

/**
 * SpringBoot整合Listener方式二
 *
 *
 */
@SpringBootApplication
public class App6 {

    public static void main(String[] args) {
        SpringApplication.run(App6.class, args);

    }
    /**
     * 注册listener
     */
    @Bean
    public ServletListenerRegistrationBean<SecondListener> getServletListenerRegistrationBean(){
        ServletListenerRegistrationBean<SecondListener> bean= new ServletListenerRegistrationBean<SecondListener>(new SecondListener());
        return bean;
    }
}

四、访问静态资源

1. SpringBoot可在classpath/static的目录下存放静态资源

2. SpringBoot可在ServletContext根目录下存放静态资源

在src/main/webapp  目录名称必须要webapp

五、文件上传

1.编写Controller类

/**
 * SpringBoot文件上传
 *
 *
 */
//@Controller
@RestController //表示该类下的方法的返回值会自动做json格式的转换
public class FileUploadController {

    /*
     * 处理文件上传
     */
    @RequestMapping("/fileUploadController")
    public Map<String, Object> fileUpload(MultipartFile filename)throws Exception{
        System.out.println(filename.getOriginalFilename());
        filename.transferTo(new File("d:/"+filename.getOriginalFilename()));
        Map<String, Object> map = new HashMap<>();
        map.put("msg", "ok");
        return map;
    }
}

2.编写启动器类

/**
 * SpringBoot文件上传
 *
 *
 */
@SpringBootApplication
public class App7 {

    public static void main(String[] args) {
        SpringApplication.run(App7.class, args);

    }
}

3.编写application.properties配置文件，设置上传文件大小的默认值

spring.servlet.multipart.max-file-size=200MB
spring.servlet.multipart.max-request-size=200MB

设置单个上传文件的大小：spring.servlet.multipart.max-file-size=200MB 

设置一次请求上传文件的总容量：spring.servlet.multipart.max-request-size=200MB

总结

本篇简单介绍了SpringBoot整合Servlet、Filter、Listener、以及SpringBoot上传文件的方式，下一篇将介绍SpringBoot视图层技术。