WebMvcConfigurer
1.概述
WebMvcConfigurer配置类其实是Spring内部的一种配置方式，采用JavaBean的形式来代替传统的xml配置文件形式进行针对框架个性化定制，可以自定义一些Handler，Interceptor，ViewResolver，MessageConverter。基于java-based方式的spring mvc配置，需要创建一个配置类并实现WebMvcConfigurer 接口；
在Spring Boot 1.5版本都是靠重写WebMvcConfigurerAdapter的方法来添加自定义拦截器，消息转换器等。SpringBoot 2.0 后，该类被标记为@Deprecated（弃用）。官方推荐直接实现WebMvcConfigurer或者直接继承WebMvcConfigurationSupport，方式一实现WebMvcConfigurer接口（推荐），方式二继承WebMvcConfigurationSupport类
视图解析器
实现：
1.实现WebMvcConfigurer接口
2.重写configureViewResolvers 该方法是用来配置视图解析器的 该方法有一个参 数ViewResolverRegistry是一个注册器 用来注册你想定义的视图解析器
/** * Configure view resolvers to translate String-based view names returned from * controllers into concrete {@link org.springframework.web.servlet.View} * implementations to perform rendering with. * @since 4.1 */ default void configureViewResolvers(ViewResolverRegistry registry) { }
3.添加@EnableWebMvc 开启个性化定制
4.覆盖configurerViewResolvers
@Configuration @ComponentScan(basePackages="com.czxy.mvc.controller") @EnableWebMvc public class MvcConfiguration implements WebMvcConfigurer { @Override public void configureViewResolvers(ViewResolverRegistry registry) { registry.jsp("/pages/",".jsp"); } }
异常处理器
异常处理器的实现方式有两种
第一种：实现类 编写实现类实现HandlerExceptionResolver接口
第二种：增强类
使用@ControllerAdvice对Controller进行增强
使用ExceptionHandler用于捕获控制器里面的异常 并进行处理？
方式一：实现HandlerExceptionResolver接口
@Component public class CustomExceptionResolver implements HandlerExceptionResolver { @Override public ModelAndView resolveException(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) { // 1 统一异常 CustomExcption customExcption = null; if(e instanceof CustomExcption) { customExcption = (CustomExcption) e; } else { customExcption = new CustomExcption("系统繁忙，请稍后重试！"); } // 2 错误信息返回 ModelAndView modelAndView = new ModelAndView(); modelAndView.addObject("message" ,customExcption.getMessage()); modelAndView.setViewName("forward:/error.jsp"); return modelAndView; } }
方式二：通知类
@CotrollerAdvice 全局异常处理
@ExceptionHandler 用来统一处理方法异常
@ControllerAdvice public class GlobalExceptionResolver { /** * 自定义异常处理器 * @param ec * @param model * @return */ @ExceptionHandler(CustomExcption.class) public String custom(CustomExcption ec, Model model) { model.addAttribute("message", ec.getMessage() + "Global"); return "forward:/error.jsp"; } /** * 其他异常处理器 * @param e * @param model * @return */ @ExceptionHandler(Exception.class) public String other(Exception e, Model model) { model.addAttribute("message", "系统繁忙，请稍后重试！" + "Global"); return "forward:/error.jsp"; } }
拦截器
preHandler：拦截器之前执行 返回true继续执行 返回false结束
postHandler：执行完Controller之后执行
afterCompletion：视图渲染完成之后完成
拦截器：
@Component public class MyInterceptor implements HandlerInterceptor { @Override public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception { System.out.println("1 拦截前"); //放行 return true; } @Override public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception { System.out.println("3 执行中"); } @Override public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception { System.out.println("5 最后完成"); } }
实现WebMvcConfigurer接口 重写addInterceptor方法 设置拦截路径
@Configuration //配置类 @ComponentScan(basePackages = {"com.czxy.inter.controller","com.czxy.inter.interceptor"}) @EnableWebMvc public class SpringMVCConfig implements WebMvcConfigurer { @Resource private MyInterceptor myInterceptor; @Override public void addInterceptors(InterceptorRegistry registry) { InterceptorRegistration interceptorRegistration1 = registry.addInterceptor(myInterceptor); interceptorRegistration1.addPathPatterns("/**"); } }
