Spring boot实现监听器

package com.example.demo.listener.test;import javax.servlet.ServletContextEvent;import javax.servlet.ServletContextListener;import javax.servlet.annotation.WebListener;/** * 使用@WebListener注解，实现ServletContextListener接口 * 在启动器处加注解@ServletComponentScan * @author cxx */@WebListenerpublic class MyServletContextListener implements ServletContextListener{    @Override    public void contextInitialized(ServletContextEvent servletContextEvent) {        System.out.println("ServletContext初始化");        System.out.println(servletContextEvent.getServletContext().getServerInfo());    }    @Override    public void contextDestroyed(ServletContextEvent servletContextEvent) {        System.out.println("ServletContext销毁");    }}package com.example.demo;import org.mybatis.spring.annotation.MapperScan;import org.springframework.boot.SpringApplication;import org.springframework.boot.autoconfigure.EnableAutoConfiguration;import org.springframework.boot.autoconfigure.SpringBootApplication;import org.springframework.boot.web.servlet.ServletComponentScan;@SpringBootApplication@MapperScan(value = "com.example.demo.mapper")//filter和listener监听器注解需要用的@ServletComponentScanpublic class DemoApplication {	public static void main(String[] args) {		SpringApplication.run(DemoApplication.class, args);	}}复制代码

Spring Boot实现过滤器

第一步：定义MyFilter过滤器

package com.example.demo.filter.test;import javax.servlet.*;import javax.servlet.annotation.WebFilter;import java.io.IOException;/** * 使用注解过滤器 * @WebFilter将一个实现了import javax.servlet.Filter接口的类定义为过滤器 * 属性filterName生命过滤器的名称，可选 * 属性urlPatterns指定要过滤的URL模式，也可使用属性value来声明（指定要过滤的URL是必选属性） */@WebFilter(filterName = "MyFilter",urlPatterns = "/*")public class MyFilter implements Filter{    @Override    public void init(FilterConfig filterConfig) throws ServletException {        System.out.println("过滤器初始化");    }    @Override    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {        System.out.println("执行过滤操作");        filterChain.doFilter(servletRequest,servletResponse);    }    @Override    public void destroy() {        System.out.println("过滤器销毁");    }}复制代码

第二部：在入口处添加@ServletComponentScan注解

package com.example.demo;import org.mybatis.spring.annotation.MapperScan;import org.springframework.boot.SpringApplication;import org.springframework.boot.autoconfigure.EnableAutoConfiguration;import org.springframework.boot.autoconfigure.SpringBootApplication;import org.springframework.boot.web.servlet.ServletComponentScan;@SpringBootApplication@MapperScan(value = "com.example.demo.mapper")//filter和listener监听器注解需要用的@ServletComponentScanpublic class DemoApplication {   public static void main(String[] args) {      SpringApplication.run(DemoApplication.class, args);   }}复制代码

Spring Boot全局异常处理

全局异常处理：@ControllerAdvice：包含@Componet,可以被扫描到

统一异常处理：@ExceptionHandler（Exception.class）:用在方法上面表示遇到这个异常就执行以下方法。

package com.example.demo.global.exception.test;import org.springframework.web.bind.annotation.GetMapping;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RequestMethod;import org.springframework.web.bind.annotation.RestController;@RestControllerpublic class ExceptionTestController {    @RequestMapping(value = "ExceptionTest",method = RequestMethod.GET)    public String index(){        String str=null;        str.split("1");        return "ExceptionTestController";    }}package com.example.demo.global.exception.test;import org.springframework.web.bind.annotation.ControllerAdvice;import org.springframework.web.bind.annotation.ExceptionHandler;import org.springframework.web.bind.annotation.ResponseBody;import org.springframework.web.servlet.ModelAndView;import javax.servlet.http.HttpServletRequest;import java.util.Date;@ControllerAdvice//如果返回的为json数据或其他对象，添加该注解@ResponseBodypublic class GlobalDefaultExceptionHandler {    public static final String DEFAULT_ERROR_VIEW="error";    @ExceptionHandler({NullPointerException.class,NumberFormatException.class})    public ModelAndView formatErrorHandler(HttpServletRequest request,Exception ex){        System.out.println("已经捕获到异常");        ModelAndView mv=new ModelAndView();        mv.addObject("exception",ex);        mv.addObject("timeStamp",new Date());        mv.setViewName(DEFAULT_ERROR_VIEW);        return mv;    }}复制代码