02.Spring Boot 实战~SpringBoot 整合Servlet,Filter, Listener

本文是上一篇文章的后续,详情点击该链接

SpringBoot 在 Controller 中常用注解

Spring boot整合Servlet

方式一:通过注解扫描完成 Servlet 组件的注册

创建Servlet

@WebServlet("/first")
public class MyServlet extends HttpServlet {
@Override
protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.getWriter().write("hello world this is my first servlet");
}
}

启动类

//启动类必须要有这个注解!
@SpringBootApplication
@ServletComponentScan// 在 spring Boot启 动 时 会 扫 描 @WebServlet
public class SpringBootDemoApplication {
public static void main(String[] args) {
//必须要通过SpringApplication下的静态方法run
//第一个参数是启动类的class，第二个参数是main方法里的args
SpringApplication.run(SpringBootDemoApplication.class,args);
}
}

方法二:通过方法完成 Servlet 组件的注册

创建Servlet

这个时候我们就不再需要@WebServlet注解了

public class MyServlet2 extends HttpServlet {
@Override
protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.getWriter().write("this is my second servlet");
}
}

创建ServletConfig类

完成Servlet组件的注册

@Configuration
public class ServletConfig {
@Bean
public ServletRegistrationBean getServletRegistrationBean(){
//实例化Servlet
ServletRegistrationBean bean = new ServletRegistrationBean(new MyServlet2());
bean.addUrlMappings("/second");
return bean;
}
}

启动类

//启动类必须要有这个注解!
@SpringBootApplication
@ServletComponentScan// 在 spring Boot启 动 时 会 扫 描 @WebServlet
public class SpringBootDemoApplication {
public static void main(String[] args) {
//必须要通过SpringApplication下的静态方法run
//第一个参数是启动类的class，第二个参数是main方法里的args
SpringApplication.run(SpringBootDemoApplication.class,args);
}
}

Spring boot 整合 Filter

方式一:通过注解扫描完成Filter组件注册

创建Filter

//拦截刚刚创建的MyServlet
@WebFilter("/first")
public class FirstFilter 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("start");
filterChain.doFilter(servletRequest,servletResponse);
System.out.println("end");
}

@Override
public void destroy() {}
}

启动类

//启动类必须要有这个注解!
@SpringBootApplication
@ServletComponentScan// 在 spring Boot启 动 时 会 扫 描 @WebServlet,@WebFilter注解

public class SpringBootDemoApplication {
public static void main(String[] args) {
//必须要通过SpringApplication下的静态方法run
//第一个参数是启动类的class，第二个参数是main方法里的args
SpringApplication.run(SpringBootDemoApplication.class,args);
}
}

方式二:通过方法完成Filter组件注册

创建新的Filter

这个时候我们不再需要@WebFilter注解了

public class FirstFilter2 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("start");
filterChain.doFilter(servletRequest,servletResponse);
System.out.println("end");
}

@Override
public void destroy() {}
}

完成Filter的注册

@Configuration
public class FilterConfig {
public FilterRegistrationBean getFilterRegistrationBean(){
FilterRegistrationBean bean = new FilterRegistrationBean(new FirstFilter2());
//拦截MyServlet
bean.addUrlPatterns(new String[]{"/first"});
return bean;
}
}

启动类

//启动类必须要有这个注解!
@SpringBootApplication
@ServletComponentScan// 在 spring Boot启 动 时 会 扫 描 @WebServlet,@WebFilter注解

public class SpringBootDemoApplication {
public static void main(String[] args) {
//必须要通过SpringApplication下的静态方法run
//第一个参数是启动类的class，第二个参数是main方法里的args
SpringApplication.run(SpringBootDemoApplication.class,args);
}
}

Spring Boot 整合 Listener

方式一:还是使用注解

@WebListener
public class FirstListener implements ServletContextListener {
@Override
public void contextInitialized(ServletContextEvent sce) {
System.out.println("Listener ....Init");
}

@Override
public void contextDestroyed(ServletContextEvent sce) {

}
}

启动类

//启动类必须要有这个注解!
@SpringBootApplication
@ServletComponentScan// 在 spring Boot启 动 时 会 扫 描 @WebServlet,@WebFilter注解,@WebListener

public class SpringBootDemoApplication {
public static void main(String[] args) {
//必须要通过SpringApplication下的静态方法run
//第一个参数是启动类的class，第二个参数是main方法里的args
SpringApplication.run(SpringBootDemoApplication.class,args);
}
}

方式二:还是通过方法完成注册

配置类

@Configuration
public class ListenerConfig {
@Bean
public ServletListenerRegistrationBean getServletListenerRegistrationBean(){
ServletListenerRegistrationBean bean = new ServletListenerRegistrationBean(new FirstListener2());
return bean;
}
}

套路都一样,我也懒得再写了。。。