SpringMVC基本工作(基于注解配置)

差不多文章

1、创建Maven工程，pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.wexiao.mvc</groupId>
    <artifactId>spring-annotation</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>war</packaging>
    <dependencies>
        <!-- SpringMVC -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>5.3.1</version>
        </dependency>
        <!-- 日志 -->
        <dependency>
            <groupId>ch.qos.logback</groupId>
            <artifactId>logback-classic</artifactId>
            <version>1.2.3</version>
        </dependency>
        <!-- ServletAPI -->
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>3.1.0</version>
            <scope>provided</scope>   <!-- provided -->
        </dependency>
        <!-- Spring5和Thymeleaf整合包 -->
        <dependency>
            <groupId>org.thymeleaf</groupId>
            <artifactId>thymeleaf-spring5</artifactId>
            <version>3.0.12.RELEASE</version>
        </dependency>
    </dependencies>
</project>

2、写一个WebInit类继承AbstractAnnotationConfigDispatcherServletInitializer，实现三个方法

//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
     */
    protected Class<?>[] getRootConfigClasses() {
        return new Class[0];
    }
    /**
     * 指定springMVC的配置类
     * @return
     */
    protected Class<?>[] getServletConfigClasses() {
        return new Class[0];
    }
    /**
     * 指定DispatcherServlet的映射规则，即url-pattern
     * @return
     */
    protected String[] getServletMappings() {
        return new String[0];
    }
}

3、创建SpringConfig、WebConfig类（使用@Configuration），修改上面方法的返回值

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

public class WebInit extends AbstractAnnotationConfigDispatcherServletInitializer {
    /**
     * 指定spring的配置类
     * @return
     */
    protected Class<?>[] getRootConfigClasses() {
        return new Class[]{SpringConfig.class};
    }
    /**
     * 指定springMVC的配置类
     * @return
     */
    protected Class<?>[] getServletConfigClasses() {
        return new Class[]{WebConfig.class};
    }
    /**
     * 指定DispatcherServlet的映射规则，即url-pattern
     * @return
     */
    protected String[] getServletMappings() {
        return new String[]{"/"};
    }
}

4、注册过滤器：在WebInit类中 按ctrl+o

/**
  * 注册过滤器
  * @return
  */
@Override
protected Filter[] getServletFilters() {
    CharacterEncodingFilter characterEncodingFilter = new CharacterEncodingFilter();
    characterEncodingFilter.setEncoding("UTF-8");
    characterEncodingFilter.setForceResponseEncoding(true);
    HiddenHttpMethodFilter hiddenHttpMethodFilter = new HiddenHttpMethodFilter();
    return new Filter[]{characterEncodingFilter,hiddenHttpMethodFilter};
}

5、编写WebConfig（SpringMVC.xml）

在WebConfig类实现WebMvcConfigurer接口，按Ctrl+o实现需要的方法

package com.wexiao.mvc.config;
import com.wexiao.mvc.interceptor.TestInterceptor;
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;
/**
 * Description: SpringMVC
 * Created by wexiao on 2022/3/25 19:56
 *
 * @version 1.0
 */
/**
 * 代替SpringMvc的配置文件
 * 1、扫描注解，2、视图解析器，3、view-controller，4、default-servlet-handler
 * 5、mvc注解驱动，6、文件上传解析器，7、异常处理，8、拦截器
 */
@Configuration  //将当前类标识为一个配置类
@ComponentScan("com.wexiao.mvc.controller")  //扫描注解
@EnableWebMvc   //开启MVC注解驱动
public class WebConfig implements WebMvcConfigurer {
    //default-servlet-handler
    public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) {
        configurer.enable();
    }
    //拦截器
    public void addInterceptors(InterceptorRegistry registry) {
        TestInterceptor testInterceptor = new TestInterceptor();
        registry.addInterceptor(testInterceptor).addPathPatterns("/**"); //添加拦截路径
        //.addInterceptor(testInterceptor).excludePathPatterns(); //添加排除路径
    }
    //view-controller
    public void addViewControllers(ViewControllerRegistry registry) {
        registry.addViewController("/hello").setViewName("hello");
    }
    //异常处理(也可以通过@Bean)
    public void configureHandlerExceptionResolvers(List<HandlerExceptionResolver> resolvers) {
        SimpleMappingExceptionResolver exceptionResolver = new SimpleMappingExceptionResolver();
        Properties prop = new Properties();
        prop.setProperty("java.long.ArithmeticException","error");
        exceptionResolver.setExceptionMappings(prop);
        exceptionResolver.setExceptionAttribute("exception");   //设置在请求域中信息的键，error.html
        resolvers.add(exceptionResolver);
    }
    //文件上传解析器        （运行时报错0.0）
    @Bean
    public MultipartResolver multipartResolver(){
        CommonsMultipartResolver commonsMultipartResolver = new CommonsMultipartResolver();
        return commonsMultipartResolver;
    }
    //Thymeleaf视图解析器
    /*<!--配置 thymeleaf 的视图解析器-->
    <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>
    下面三个方法 从里到外创建 bean,然后调用
    */
    //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;
    }
}