SpringBoot学习笔记-4：第四章 Spring Boot Web 开发（3）

<!-- 1、抽取公共片段 -->
<div th:fragment="copy">content</div>
<!-- 2、引入公共片段 -->
<div th:insert="~{footer::copy}">content</div>
<!-- 3、默认效果 -->
<!-- insert功能片段在div标签中 -->

~{templateName::selector} 模板名::选择器
~{templateName::fragmentName}模板名::片段名

<input type="hidden" name="_method" value="put" th:if="${emp!=null}" />

错误页面
ErrorMvcAutoConfiguration
有模板引擎的情况下

package com.example.demo.controller;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.ResponseBody;
import java.util.HashMap;
import java.util.Map;
@ControllerAdvice
public class ExceptionController {
    @ResponseBody
    @ExceptionHandler
    public Map<String, Object> handleException(Exception e){
        Map<String, Object> map = new HashMap<>();
        map.put("code", -1);
        map.put("msg", e.getMessage());
        return map;
    }
}

{
  "msg": "用户不存在",
  "code": -1
}

# servlet配置
server.port=8001
server.context-path=/demo
# Tomcat配置
server.tomcat.uri-encoding=UTF-8

package com.example.demo.servlet;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
public class MyServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.getWriter().println("MyServlet");
    }
}

package com.example.demo.filter;
import javax.servlet.*;
import java.io.IOException;
public class MyFilter implements Filter {
    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        System.out.println("MyFilter");
        chain.doFilter(request, response);
    }
}

package com.example.demo.listener;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
public class MyListener implements ServletContextListener {
    @Override
    public void contextInitialized(ServletContextEvent sce) {
        System.out.println("contextInitialized");
    }
    @Override
    public void contextDestroyed(ServletContextEvent sce) {
        System.out.println("contextDestroyed");
    }
}

package com.example.demo.config;
import com.example.demo.filter.MyFilter;
import com.example.demo.listener.MyListener;
import com.example.demo.servlet.MyServlet;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.boot.web.servlet.ServletListenerRegistrationBean;
import org.springframework.boot.web.servlet.ServletRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import java.util.Arrays;
/**
 * 注册Servlet/Filter/Listener组件
 */
@Configuration
public class MyServletConfig {
    @Bean
    public ServletRegistrationBean myServlet(){
        ServletRegistrationBean registrationBean = new ServletRegistrationBean();
        registrationBean.setServlet(new MyServlet());
        registrationBean.setUrlMappings(Arrays.asList("/servlet"));
        return registrationBean;
    }
    @Bean
    public FilterRegistrationBean myFilter(){
        FilterRegistrationBean registrationBean = new FilterRegistrationBean();
        registrationBean.setFilter(new MyFilter());
        registrationBean.setUrlPatterns(Arrays.asList("/servlet"));
        return registrationBean;
    }
    @Bean
    public ServletListenerRegistrationBean myListener(){
        ServletListenerRegistrationBean registrationBean = new ServletListenerRegistrationBean(new MyListener());
        return registrationBean;
    }
}