SpringMVC--注解配置SpringMVC_springmvc 注解配置-优快云博客

本文链接：https://blog.youkuaiyun.com/sdau_20171819/article/details/123234725

本文介绍了如何在Servlet 3.0环境中使用Java配置类和注解替代传统的web.xml和Spring MVC配置文件。首先，创建一个初始化类`WebInit`继承自`AbstractAnnotationConfigDispatcherServletInitializer`，用于配置Servlet容器。接着，定义`SpringConfig`和`webConfig`两个配置类，分别代替Spring应用上下文和Spring MVC的配置。在`webConfig`中，配置了视图解析器、拦截器、异常处理等。通过这种方式，可以实现更加灵活和模块化的配置管理。

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使用配置类和注解代替web.xml和SpringMVC配置文件的功能

1、创建初始化类，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。

package com.java.mvc.config;

import org.springframework.web.filter.CharacterEncodingFilter;
import org.springframework.web.filter.HiddenHttpMethodFilter;
import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;

import javax.servlet.Filter;

//web工程的初始化类  用来代替web.xml
public class WebInit  extends AbstractAnnotationConfigDispatcherServletInitializer {


    /**
     * 指定spring的配置类
     * @return
     */
    @Override
    protected Class<?>[] getRootConfigClasses() {
        return new Class[]{SpringConfig.class};
    }

    /**
     * 指定springMVC的配置类
     * @return
     */
    @Override
    protected Class<?>[] getServletConfigClasses() {
        return new Class[]{webConfig.class};
    }

    /**
     * 指定DispatcherServlet的映射规则  即url-pattern
     * @return
     */
    @Override
    protected String[] getServletMappings() {
        return new String[]{"/"};
    }

    /**
     * 注册过滤器
     * @return
     */
    @Override
    protected Filter[] getServletFilters() {
        //设置编码格式的过滤器
        CharacterEncodingFilter characterEncodingFilter = new CharacterEncodingFilter();
        characterEncodingFilter.setEncoding("UTF-8");
        characterEncodingFilter.setForceRequestEncoding(true);
        //设置put delete请求的过滤器
        HiddenHttpMethodFilter hiddenHttpMethodFilter = new HiddenHttpMethodFilter();
        //返回过滤器数组
        return new Filter[]{characterEncodingFilter,hiddenHttpMethodFilter};
    }
}

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">

    <!--
    过滤器执行顺序根据filter-mapping 顺序执行
    因此先设置编码的过滤器
  -->
    <!--配置编码格式-->
    <filter>
        <filter-name>CharacterEncodingFilter</filter-name>
        <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
        <init-param>
            <param-name>encoding</param-name>
            <param-value>UTF-8</param-value>
        </init-param>
        <init-param>
            <param-name>forceResponseEncoding</param-name>
            <param-value>true</param-value>
        </init-param>
    </filter>
    <filter-mapping>
        <filter-name>CharacterEncodingFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

    <!-- 配置put delete请求-->
    <filter>
        <filter-name>HiddenHttpMethodFilter</filter-name>
        <filter-class>org.springframework.web.filter.HiddenHttpMethodFilter</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>HiddenHttpMethodFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

    <!--配置MVC servlet-->
    <servlet>
        <servlet-name>DispatcherServlet</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:springMVC.xml</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>DispatcherServlet</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>

</web-app>

2、创建SpringConfig配置类，代替spring的配置文件

@Configuration
public class SpringConfig {
	//ssm整合之后，spring的配置信息写在此类中
}

3、创建WebConfig配置类，代替SpringMVC的配置文件

package com.java.mvc.config;

import com.java.mvc.interceptor.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.multipart.MultipartResolver;
import org.springframework.web.multipart.commons.CommonsMultipartResolver;
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 java.util.List;
import java.util.Properties;

//代替springmvc的配置文件
/**
 * 1. 扫描组件
 * 2.视图解析器
 * 3.view-controller
 * 4.静态资源访问  default-servlet-handler
 * 5.MVC注解驱动 annotation-driven
 * 6.文件上传解析器
 * 7.异常处理
 * 8.拦截器
 */
@Configuration
@ComponentScan("com.java.mvc.controller")
@EnableWebMvc  // 开启MVC注解驱动
public class webConfig implements WebMvcConfigurer {
    //视图解析器
    //配置生成模板解析器
    @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;
    }

    //4.静态资源访问  default-servlet-handler
    @Override
    public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) {
        configurer.enable();
    }

    //配置拦截器
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        FirstInterceptor firstInterceptor = new FirstInterceptor();
        registry.addInterceptor(firstInterceptor).addPathPatterns("/**");
    }

    //view-controller 实现跳转页面
    @Override
    public void addViewControllers(ViewControllerRegistry registry) {
        registry.addViewController("/hello").setViewName("hello");
    }

    //文件上传解析器
    @Bean
    public MultipartResolver multipartResolver(){
        CommonsMultipartResolver commonsMultipartResolver = new CommonsMultipartResolver();
        return commonsMultipartResolver;
    }

    //异常处理
    @Override
    public void configureHandlerExceptionResolvers(List<HandlerExceptionResolver> resolvers) {
        //创建异常处理 将异常处理放在list集合中
        SimpleMappingExceptionResolver exceptionResolver = new SimpleMappingExceptionResolver();
        Properties prop = new Properties();
        //添加异常   跳转页面
        prop.setProperty("java.lang.ArithmeticException","error");
        exceptionResolver.setExceptionMappings(prop);
        //获取异常信息
        exceptionResolver.setExceptionAttribute("exception");
        resolvers.add(exceptionResolver);
    }
}

springmvc.xml

<?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 http://www.springframework.org/schema/context/spring-context.xsd
                          http://www.springframework.org/schema/mvc https://www.springframework.org/schema/mvc/spring-mvc.xsd">

    <!--配置扫描组件-->
    <context:component-scan base-package="com.java"></context:component-scan>
    <!--视图组件-->
    <!-- 配置Thymeleaf视图解析器 -->
    <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">
                        <!-- 视图前缀 -->
                        <property name="prefix" value="/WEB-INF/templates/"/>
                        <!-- 视图后缀 -->
                        <property name="suffix" value=".html"/>
                        <property name="templateMode" value="HTML5"/>
                        <property name="characterEncoding" value="UTF-8" />
                    </bean>
                </property>
            </bean>
        </property>
    </bean>

    <!--
    如果controller类中的方法仅仅是用来实现页面跳转，则可以通过mvc:view-controller实现功能
     path： 设置处理请求路径  @RequestMapping里面的内容
     view-name： 设置请求地址所对应的视图名称
     但是这样写以后，页面内的MVC跳转功能不能使用，需要打开mvc注解驱动
    -->
    <mvc:view-controller path="/" view-name="index"></mvc:view-controller>


    <!--开放对静态资源的访问-->
    <mvc:default-servlet-handler></mvc:default-servlet-handler>
    <!-- 开启mvc注解驱动-->
    <mvc:annotation-driven/>

    <!--
    一个bean对象
    必须通过文件解析器的解析才能将文件转换为MultipartFile对象
    并且必须设置id,controller才能通过id来获取到这个对象
    -->
    <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver"></bean>

    <!-- 配置拦截器  全部拦截-->
    <mvc:interceptors>
        <!-- bean 和 ref 会对所有的请求都进行拦截-->
       <!--  <bean class="com.java.mvc.Interceptor.FirstInterceptor"></bean> -->
      <!--   <ref bean="firstInterceptor"></ref> -->
<!--        <mvc:interceptor>-->
<!--            <mvc:mapping path="/**"/>-->
<!--            <mvc:exclude-mapping path="/"/>-->
<!--            &lt;!&ndash; 指定拦截器&ndash;&gt;-->
<!--            <ref bean="firstInterceptor"></ref>-->
<!--        </mvc:interceptor>-->
        <bean class="com.java.mvc.Interceptor.FirstInterceptor"></bean>
        <bean class="com.java.mvc.Interceptor.SecondInterceptor"></bean>
    </mvc:interceptors>

</beans>

4、测试功能

 @RequestMapping("/")
    public String test(){
        return "index";
    }

    @RequestMapping("/testError")
    public String test2(){
        int a = 5/0;
        return "success";
    }