分析講解SpringMVC注解配置如何實現(xiàn)

更新時間：2022年05月16日 08:38:18 作者：仰望星空的快樂

這篇文章主要介紹了本文要介紹用注解方式代替web.xml與SpringMVC的配置文件,對大家的學習或工作具有一定的參考借鑒價值,需要的朋友可以參考下

簡介

使用配置類和注解代替web.xml和SpringMVC配置文件的功能

在Servlet3.0環(huán)境中，容器會在類路徑中查找實現(xiàn)javax.servlet.ServletContainerInitializer接口的類，如果找到的話就用它來配置Servlet容器。 Spring提供了這個接口的實現(xiàn)，名為SpringServletContainerInitializer，這個類又會查找實現(xiàn)WebApplicationInitializer的類并將配置的任務(wù)交給它們來完成。Spring3.2引入了一個便利的WebApplicationInitializer基礎(chǔ)實現(xiàn)，名為AbstractAnnotationConfigDispatcherServletInitializer，當我們的類擴展了AbstractAnnotationConfigDispatcherServletInitializer并將其部署到Servlet3.0容器的時候，容器會自動發(fā)現(xiàn)它，并用它來配置Servlet上下文。

意思就是容器會自動發(fā)現(xiàn)繼承了AbstractAnnotationConfigDispatcherServletInitializer的子類，并用它來配置servlet上下文。（用來代替web.xml）

注解類代替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過濾器   spring  springmvc的配置類    dispracture的映射路徑
public class webXml extends AbstractAnnotationConfigDispatcherServletInitializer {
    //    指定spring配置類
    @Override
    protected Class<?>[] getRootConfigClasses() {
        return new Class[] {SpringConfig.class};
    }
    //    指定springmvc配置類
    @Override
    protected Class<?>[] getServletConfigClasses() {
        return new Class[]{SpringMvcConfig.class};
    }
    //    指定dispracture的映射路徑 即url-pattern
    @Override
    protected String[] getServletMappings() {
        return new String[]{"/"};
    }
//注冊編碼過濾器
    @Override
    protected Filter[] getServletFilters() {
        CharacterEncodingFilter encodingFilter = new CharacterEncodingFilter();
        encodingFilter.setEncoding("UTF-8");
        encodingFilter.setForceRequestEncoding(true);
        HiddenHttpMethodFilter hiddenHttpMethodFilter = new HiddenHttpMethodFilter();
        return new Filter[]{encodingFilter, hiddenHttpMethodFilter};
    }
}

注解類代替Spring-mvc.xml

Spring-mvc配置文件（不管是xml還是注解的類）有如下八個功能

視圖解析器
掃描包的范圍（組件掃描）
view-controller（只返回視圖的控制方法）
defalut-servlet-handler 靜態(tài)資源處理
mvc注解驅(qū)動
文件上傳解析器
異常處理
攔截器

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視圖解析器   2掃描包的范圍（組件掃描）  3view-controller（只返回視圖的控制方法）  4defalut-servlet-handler  靜態(tài)資源處理和
//5  mvc注解驅(qū)動  6文件上傳解析器   7異常處理   8攔截器
//代替springmvc的配置文件
//掃描包的范圍（組件掃描）
@ComponentScan("com.hxut.rj1192")
//開啟MVC注解驅(qū)動
@EnableWebMvc
@Configuration
public class SpringMvcConfig implements WebMvcConfigurer {
    //配置視圖解析器
//    這個注解是將類放進ioc容器中  因為web.xml中就是嵌套的,
    @Bean
    public ITemplateResolver templateResolver() {
        WebApplicationContext webApplicationContext = ContextLoader.getCurrentWebApplicationContext();
        // ServletContextTemplateResolver需要一個ServletContext作為構(gòu)造參數(shù)，可通過WebApplicationContext 的方法獲得
        ServletContextTemplateResolver templateResolver = new ServletContextTemplateResolver(
                webApplicationContext.getServletContext());
        templateResolver.setPrefix("/WEB-INF/templates/");
        templateResolver.setSuffix(".html");
        templateResolver.setCharacterEncoding("UTF-8");
        templateResolver.setTemplateMode(TemplateMode.HTML);
        return templateResolver;
    }
    //生成模板引擎并為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;
    }
    //生成視圖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("/");是設(shè)置攔截的url
//        excludePathPatterns(); 是設(shè)置不攔截的url
        registry.addInterceptor(interceptorRegistry).addPathPatterns("/");
    }
//視圖控制器
    @Override
    public void addViewControllers(ViewControllerRegistry registry) {
      registry.addViewController("/hello").setViewName("succes");
    }
    //配置文件上傳解析器
    @Bean
    public CommonsMultipartResolver multipartResolver(){
        CommonsMultipartResolver commonsMultipartResolver=new CommonsMultipartResolver();
        return commonsMultipartResolver;
    }
    //配置異常映射
    @Override
    public void configureHandlerExceptionResolvers(List<HandlerExceptionResolver> resolvers) {
        SimpleMappingExceptionResolver exceptionResolver = new SimpleMappingExceptionResolver();
        Properties prop = new Properties();
        prop.setProperty("java.lang.ArithmeticException", "error");
        //設(shè)置異常映射
        exceptionResolver.setExceptionMappings(prop);
        //設(shè)置共享異常信息的鍵
        exceptionResolver.setExceptionAttribute("ex");
        resolvers.add(exceptionResolver);
    }
}

全用xml寫：

<?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">
      <!--2.掃描包的范圍（組件掃描）-->
    <context:component-scan base-package="com.hxut.rj1192.zyk"/>
    <!-- 1.配置Thymeleaf視圖解析器 -->
    <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>
    <!--4.靜態(tài)資源處理-->
    <mvc:default-servlet-handler/>
    <!--5.mvc注解驅(qū)動-->
    <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.文件上傳解析器-->
    <bean id="multipartResolver"
          class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
    </bean>
<! --7.異常處理-->
    <bean class="org.springframework.web.servlet.handler.SimpleMappingExceptionResolver">
            <property name="exceptionMappings">
                <props>
                    <prop key="java.lang.ArithmeticException">error</prop>
                </props>
            </property>
            <!--        將錯誤信息放到ex這個變量中，并放進model中-->
            <property name="exceptionAttribute" value="ex"></property>
        </bean>
<! --8.攔截器-->
 <mvc:interceptors>
        <ref bean="first"></ref>
        <ref bean="second"></ref>
    </mvc:interceptors>
</beans>

攔截器文件

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 執(zhí)行");
        return true;
    }
    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        System.out.println("posthandle 執(zhí)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 執(zhí)行");
        HandlerInterceptor.super.afterCompletion(request, response, handler, ex);
    }
}

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