13、注解配置springmvc

使用配置类和注解代替web.xml和SpringMVC配置文件的功能

13.1、创建初始化的类，代替web.xml

在Servlet3.0环境中，容器会在类路径中查找实现javax.servlet.ServletContainerInitializer接口的类，如果找到的话就用它来配置Servlet容器。 Spring提供了这个接口的实现，名为

SpringServletContainerInitializer，这个类反过来又会查找实现WebApplicationInitializer的类并将配置的任务交给它们来完成。Spring3.2引入了一个便利的WebApplicationInitializer基础实现，名为AbstractAnnotationConfigDispatcherServletInitializer，当我们的类扩展了

AbstractAnnotationConfigDispatcherServletInitializer并将其部署到Servlet3.0容器的时候，容器会自动发现它，并用它来配置Servlet上下文。

13.2、使用流程

1. 声明一个类来继承AbstractAnnotationConfigDispatcherServletInitializer，并且实现他的抽象方法

2. 实现配置SpringConfig的java文件

   @Overrideprotected Class<?>[] getRootConfigClasses() {return new Class[]{SpringConfig.class};}
   

3. 实现SpringMvcConfig的java文件

   @Override
   protected Class<?>[] getServletConfigClasses() {return new Class[]{SpringMvcConfig.class};
   }
   

13.3、实例代码

1.继承AbstractAnnotationConfigDispatcherServletInitializer的java文件

/*** @author ning0* @date 2024/6/25 22:24* @description WebInit*/
public class WebInit extends AbstractAnnotationConfigDispatcherServletInitializer {//加载spring配置类@Overrideprotected Class<?>[] getRootConfigClasses() {return new Class[]{SpringConfig.class};}//加载springmvc配置类@Overrideprotected Class<?>[] getServletConfigClasses() {return new Class[]{SpringMvcConfig.class};}//设置DispatcherServlet的url-pattern@Overrideprotected String[] getServletMappings() {return new String[]{"/"};}@Overrideprotected Filter[] getServletFilters() {// 创建编码过滤器CharacterEncodingFilter characterEncodingFilter = new CharacterEncodingFilter();// 设置编码格式characterEncodingFilter.setEncoding("UTF-8");// 设置强制编码characterEncodingFilter.setForceEncoding(true);// 创建请求方式的过滤器HiddenHttpMethodFilter hiddenHttpMethodFilter = new HiddenHttpMethodFilter();return new Filter[]{characterEncodingFilter, hiddenHttpMethodFilter};}
}

2.SpringMvcConfig.java文件

package com.qc.config;import com.qc.interceptors.FirstInterceptor;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.context.ContextLoader;
import org.springframework.web.context.WebApplicationContext;
import org.springframework.web.servlet.HandlerExceptionResolver;
import org.springframework.web.servlet.ViewResolver;
import org.springframework.web.servlet.config.annotation.*;
import org.springframework.web.servlet.handler.SimpleMappingExceptionResolver;
import org.thymeleaf.spring5.SpringTemplateEngine;
import org.thymeleaf.spring5.view.ThymeleafViewResolver;
import org.thymeleaf.templatemode.TemplateMode;
import org.thymeleaf.templateresolver.ITemplateResolver;
import org.thymeleaf.templateresolver.ServletContextTemplateResolver;import javax.servlet.ServletContext;
import java.util.List;
import java.util.Properties;/*** @author ning0* @date 2024/6/25 22:27* @description SpringMvcConfig*/
// 配置类
@Configuration
// 扫描controller
@ComponentScan("com.qc.controller")
// 开启SpringMvc注解
@EnableWebMvc
public class SpringMvcConfig implements WebMvcConfigurer {// 默认servlet处理器 静态资源映射@Overridepublic void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) {configurer.enable();}@Override// 配置视图控制器public void addViewControllers(ViewControllerRegistry registry) {registry.addViewController("/").setViewName("index");}@Overridepublic void addInterceptors(InterceptorRegistry registry) {FirstInterceptor firstInterceptor = new FirstInterceptor();registry.addInterceptor(firstInterceptor).addPathPatterns("/**").excludePathPatterns("/");}// 异常解析器@Overridepublic void configureHandlerExceptionResolvers(List<HandlerExceptionResolver> resolvers) {SimpleMappingExceptionResolver simpleMappingExceptionResolver = new SimpleMappingExceptionResolver();Properties properties = new Properties();properties.setProperty("java.lang.ArithmeticException", "error");simpleMappingExceptionResolver.setExceptionMappings(properties);simpleMappingExceptionResolver.setExceptionAttribute("ex");resolvers.add(simpleMappingExceptionResolver);}// 配置视图解析器@Beanpublic ITemplateResolver templateResolver() {WebApplicationContext webApplicationContext = ContextLoader.getCurrentWebApplicationContext();ServletContextTemplateResolver templateResolver = new ServletContextTemplateResolver(webApplicationContext.getServletContext());templateResolver.setPrefix("/WEB-INF/pages/");templateResolver.setSuffix(".html");templateResolver.setCharacterEncoding("UTF-8");templateResolver.setTemplateMode(TemplateMode.HTML);return templateResolver;}// 配置模板引擎@Beanpublic SpringTemplateEngine templateEngine(ITemplateResolver templateResolver) {SpringTemplateEngine templateEngine = new SpringTemplateEngine();templateEngine.setTemplateResolver(templateResolver);return templateEngine;}// 配置视图解析器注入引擎@Beanpublic ViewResolver viewResolver(SpringTemplateEngine templateEngine) {ThymeleafViewResolver viewResolver = new ThymeleafViewResolver();viewResolver.setCharacterEncoding("UTF-8");viewResolver.setTemplateEngine(templateEngine);return viewResolver;}}

3.SpringConfig.java

package com.qc.config;import org.springframework.context.annotation.Configuration;/*** @author ning0* @date 2024/6/25 22:26* @description SpringConfig*///将该类标注为配置类
@Configuration
public class SpringConfig {}

g.springframework.context.annotation.Configuration;

/**

• @author ning0
• @date 2024/6/25 22:26
• @description SpringConfig
  */

//将该类标注为配置类
@Configuration
public class SpringConfig {

}