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分析讲解SpringMVC注解配置如何实现

作者：仰望星空的快乐　　发布时间：2023-10-30 17:23:58　

标签：Java,注解,配置,SpringMVC

简介

使用配置类和注解代替web.xml和SpringMVC配置文件的功能

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。

意思就是容器会自动发现继承了AbstractAnnotationConfigDispatcherServletInitializer的子类，并用它来配置servlet上下文。（用来代替web.xml）

注解类代替web.xml

package com.hxut.rj1192.annoation;
import org.springframework.web.filter.CharacterEncodingFilter;
import org.springframework.web.filter.HiddenHttpMethodFilter;
import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;
import javax.servlet.Filter;
//代替web.xml filter过滤器 spring springmvc的配置类 dispracture的映射路径
public class webXml extends AbstractAnnotationConfigDispatcherServletInitializer {
// 指定spring配置类
@Override
protected Class<?>[] getRootConfigClasses() {
return new Class[] {SpringConfig.class};
}
// 指定springmvc配置类
@Override
protected Class<?>[] getServletConfigClasses() {
return new Class[]{SpringMvcConfig.class};
}
// 指定dispracture的映射路径即url-pattern
@Override
protected String[] getServletMappings() {
return new String[]{"/"};
}
//注册编码过滤器
@Override
protected Filter[] getServletFilters() {
CharacterEncodingFilter encodingFilter = new CharacterEncodingFilter();
encodingFilter.setEncoding("UTF-8");
encodingFilter.setForceRequestEncoding(true);
HiddenHttpMethodFilter hiddenHttpMethodFilter = new HiddenHttpMethodFilter();
return new Filter[]{encodingFilter, hiddenHttpMethodFilter};
}
}

注解类代替Spring-mvc.xml

Spring-mvc配置文件（不管是xml还是注解的类）有如下八个功能

视图解析器
扫描包的范围（组件扫描）
view-controller（只返回视图的控制方法）
defalut-servlet-handler 静态资源处理
mvc注解驱动
文件上传解析器
异常处理
*

package com.hxut.rj1192.annoation;
import com.hxut.rj1192.InterceptorRegistry01;
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.multipart.commons.CommonsMultipartResolver;
import org.springframework.web.servlet.HandlerExceptionResolver;
import org.springframework.web.servlet.HandlerInterceptor;
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 java.util.List;
import java.util.Properties;
//1视图解析器 2扫描包的范围（组件扫描） 3view-controller（只返回视图的控制方法） 4defalut-servlet-handler 静态资源处理和
//5 mvc注解驱动 6文件上传解析器 7异常处理 8 *
//代替springmvc的配置文件
//扫描包的范围（组件扫描）
@ComponentScan("com.hxut.rj1192")
//开启MVC注解驱动
@EnableWebMvc
@Configuration
public class SpringMvcConfig implements WebMvcConfigurer {
//配置视图解析器
// 这个注解是将类放进ioc容器中因为web.xml中就是嵌套的,
@Bean
public ITemplateResolver templateResolver() {
WebApplicationContext webApplicationContext = ContextLoader.getCurrentWebApplicationContext();
// ServletContextTemplateResolver需要一个ServletContext作为构造参数，可通过WebApplicationContext 的方法获得
ServletContextTemplateResolver templateResolver = new ServletContextTemplateResolver(
webApplicationContext.getServletContext());
templateResolver.setPrefix("/WEB-INF/templates/");
templateResolver.setSuffix(".html");
templateResolver.setCharacterEncoding("UTF-8");
templateResolver.setTemplateMode(TemplateMode.HTML);
return templateResolver;
}
//生成模板引擎并为模板引擎注入模板解析器
@Bean
public SpringTemplateEngine templateEngine(ITemplateResolver templateResolver) {
SpringTemplateEngine templateEngine = new SpringTemplateEngine();
templateEngine.setTemplateResolver(templateResolver);
return templateEngine;
}
//生成视图解析器并未解析器注入模板引擎
@Bean
public ViewResolver viewResolver(SpringTemplateEngine templateEngine) {
ThymeleafViewResolver viewResolver = new ThymeleafViewResolver();
viewResolver.setCharacterEncoding("UTF-8");
viewResolver.setTemplateEngine(templateEngine);
return viewResolver;
}
//default-servlet configuure
@Override
public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) {
WebMvcConfigurer.super.configureDefaultServletHandling(configurer);
}
@Override
public void addInterceptors(InterceptorRegistry registry) {
InterceptorRegistry01 interceptorRegistry=new InterceptorRegistry01();
// addPathPatterns("/");是设置拦截的url
// excludePathPatterns(); 是设置不拦截的url
registry.addInterceptor(interceptorRegistry).addPathPatterns("/");
}
//视图控制器
@Override
public void addViewControllers(ViewControllerRegistry registry) {
registry.addViewController("/hello").setViewName("succes");
}
//配置文件上传解析器
@Bean
public CommonsMultipartResolver multipartResolver(){
CommonsMultipartResolver commonsMultipartResolver=new CommonsMultipartResolver();
return commonsMultipartResolver;
}
//配置异常映射
@Override
public void configureHandlerExceptionResolvers(List<HandlerExceptionResolver> resolvers) {
SimpleMappingExceptionResolver exceptionResolver = new SimpleMappingExceptionResolver();
Properties prop = new Properties();
prop.setProperty("java.lang.ArithmeticException", "error");
//设置异常映射
exceptionResolver.setExceptionMappings(prop);
//设置共享异常信息的键
exceptionResolver.setExceptionAttribute("ex");
resolvers.add(exceptionResolver);
}
}

全用xml写：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/mvc https://www.springframework.org/schema/mvc/spring-mvc.xsd">

<context:component-scan base-package="com.hxut.rj1192.zyk"/>

<bean id="viewResolver" class="org.thymeleaf.spring5.view.ThymeleafViewResolver">
<property name="order" value="1"/>
<property name="characterEncoding" value="UTF-8"/>
<property name="templateEngine">
<bean class="org.thymeleaf.spring5.SpringTemplateEngine">
<property name="templateResolver">
<bean class="org.thymeleaf.spring5.templateresolver.SpringResourceTemplateResolver">
<property name="prefix" value="/WEB-INF/templates/"/>
<property name="suffix" value=".html"/>
<property name="templateMode" value="HTML5"/>
<property name="characterEncoding" value="UTF-8"/>
</bean>
</property>
</bean>
</property>
</bean>

<mvc:default-servlet-handler/>

<mvc:annotation-driven/>
<mvc:interceptors>
<bean class="com.hxut.rj1192.zyk.interceptor.interceptor01"/>
</mvc:interceptors>
<bean class="org.springframework.web.servlet.handler.SimpleMappingExceptionResolver">
<property name="exceptionMappings">
<props>
<prop key="java.lang.ArithmeticException">error</prop>
</props>
</property>
<property name="exceptionAttribute" value="ex"></property>
</bean>
<! --3.view-controller-->
<mvc:view-controller path="/testView" view-name="success"></mvc:view-controller>
<! --4.文件上传解析器-->
<bean id="multipartResolver"
class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
</bean>
<! --7.异常处理-->
<bean class="org.springframework.web.servlet.handler.SimpleMappingExceptionResolver">
<property name="exceptionMappings">
<props>
<prop key="java.lang.ArithmeticException">error</prop>
</props>
</property>

<property name="exceptionAttribute" value="ex"></property>
</bean>
<! --8. * -->
<mvc:interceptors>
<ref bean="first"></ref>
<ref bean="second"></ref>
</mvc:interceptors>
</beans>

* 文件

package com.hxut.rj1192;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class InterceptorRegistry01 implements HandlerInterceptor {
@Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
System.out.println("prehandle 执行");
return true;
}
@Override
public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
System.out.println("posthandle 执行");
HandlerInterceptor.super.postHandle(request, response, handler, modelAndView);
}
@Override
public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
System.out.println("afterhandle 执行");
HandlerInterceptor.super.afterCompletion(request, response, handler, ex);
}
}

来源：https://blog.csdn.net/sharesb/article/details/124715584

投稿

分析讲解SpringMVC注解配置如何实现

简介

注解类代替web.xml

注解类代替Spring-mvc.xml

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