Spring-mvc-study

springmvc-首页访问

jar包依赖

<dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>5.3.16</version>
        </dependency>
        <dependency>
            <groupId>ch.qos.logback</groupId>
            <artifactId>logback-classic</artifactId>
            <version>1.2.3</version>
        </dependency>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>3.1.0</version>
        </dependency>
        <dependency>
            <groupId>org.thymeleaf</groupId>
            <artifactId>thymeleaf-spring5</artifactId>
            <version>3.0.12.RELEASE</version>
        </dependency>

web.xml

<!--    配置springmvc前端控制器，对浏览器发送的请求统一处理-->
    <servlet>
        <servlet-name>springmvcdemo</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<!--        配置springmvc的配置文件的 位置 和 名称-->
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:springMVC.xml</param-value>
        </init-param>
<!--       将前端控制器dispatcherServlet的初始化时间 提前到 服务器 启动时-->
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>springmvcdemo</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>

springMVC.xml配置

<!--    配置组件扫描-->
  <context:component-scan base-package="com.miao.controller"></context:component-scan>

    <!-- 配置Thymeleaf视图解析器 -->
    <bean id="viewResolver" class="org.thymeleaf.spring5.view.ThymeleafViewResolver">
<!--        优先级-->
        <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>

访问页面

web.xml

webapp

@requestmapping-value

alt + 7 查看 structure

@AliasFor("path")
String[] value() default {};

可以多个地址访问同一个页面

@requestmapping-method

多个请求方法方式

@requestmapping-params

请求路径携带参数

@PathVariable

原生servletapi 调用

@RequestParam

结果

域对象共享数据

servletAPI共享数据

modelandview共享数据

model

map

modelmap

model–modelmap–map关系

modelmap

model

map

实现

dispatcherServlet流程

对应

springMVC的视图

thymeleaf解析器

dispatcherservlet–processdispatchresult–render

forward转发–地址不变

执行

第一次请求

第二次请求

redirect重定向–两次请求

view-controller

mvc中用来制定首页

<!--    path:设置处理的 请求地址，view-name:请求地址对应的视图名称-->
    <mvc:view-controller path="/" view-name="index"></mvc:view-controller>
<!--    开启注解驱动-->
    <mvc:annotation-driven/>

restful中的请求方式

开放对静态资源的访问

对静态资源的访问

先是dispatcherservlet寻找–若找不到，交给默认的defaultservlet找

httpMessageConverter–报文信息转换

提供了两个注解和类型

• @requestbody———requestentity
• @responsebody———–responseentity

将请求报文转换为java对象

将java对象转换为响应报文

@responsebody

不走视图，返回字符-succes-

json–返回对象

拦截器的配置

springMVC中的拦截器用于dispatcherservlet

• prehandle:控制器方法执行之前执行，返回类型boolean，返回true放行，false表示拦截
• posthandle：控制器方法执行之后执行
• aftercomplation:处理完视图和模型视图，渲染视图后执行

拦截器配置

//配置拦截器
@Component
public class FirstInterceptor implements HandlerInterceptor {
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        System.out.println("prehandler");
        return HandlerInterceptor.super.preHandle(request, response, handler);
//        return false;
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        System.out.println("postHandle");
        HandlerInterceptor.super.postHandle(request, response, handler, modelAndView);
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        System.out.println("afterCompletion");
        HandlerInterceptor.super.afterCompletion(request, response, handler, ex);
    }
}

@Component
public class SecondInterceptor implements HandlerInterceptor {。。。。}

springmvc.xml配置

<!--    配置拦截器_三种方式-->
    <mvc:interceptors>
<!--        <bean class="com.miao.controller.interceptor.FirstInterceptor"></bean>-->
<!--        <ref bean="firstInterceptor"></ref>-->
        <mvc:interceptor>
            <mvc:mapping path="/**"/>
            <mvc:exclude-mapping path="/"/>
            <ref bean="firstInterceptor"></ref>
        </mvc:interceptor>
    </mvc:interceptors>

三个拦截方法

prehandle

控制器之前执行–按照遍历的顺序

posthandle

控制器之后执行–遍历–倒叙执行

aftercomplation

渲染视图之后执行–遍历–倒叙执行

基于配置异常处理

显示结果

xml中配置

基于注解配置异常处理

注解配置springmvc

用于替换springmvc.xml

/**
 * 组件扫描  thymeleaf视图解析器  首页跳转view-controller  静态资源访问default-servlet-handler
 * 注解驱动annotation-driven  SimpleMappingExceptionResolver异常处理
 */
//标识为配置类
@Configuration
//开启组件扫描
@ComponentScan("com.miao.mvc")
//开区注解驱动
@EnableWebMvc
public class Webconfig implements WebMvcConfigurer {

    //替换springmvc.xml中的视图解析
    //配置生成模板解析器
    @Bean
    public ITemplateResolver contextTemplateResolver(){
        WebApplicationContext webApplicationContext = ContextLoader.getCurrentWebApplicationContext();
        ServletContextTemplateResolver contextTemplateResolver = new ServletContextTemplateResolver(
                webApplicationContext.getServletContext()
        );
        contextTemplateResolver.setPrefix("/WEB-INF/templates/");
        contextTemplateResolver.setSuffix(".html");
        contextTemplateResolver.setCharacterEncoding("UTF-8");
        contextTemplateResolver.setTemplateMode(TemplateMode.HTML);
        return contextTemplateResolver;
    }
    //生成模板引擎 并为 模板引擎 注入模板解析器
    @Bean
    public SpringTemplateEngine templateEngine(ITemplateResolver contextTemplateResolver){
        SpringTemplateEngine templateEngine = new SpringTemplateEngine();
        templateEngine.setTemplateResolver(contextTemplateResolver);
        return templateEngine;
    }
    //生成视图解析器 并为 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;
    }

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

    //配置拦截器 /*:拦截一层  /**：拦截所有层
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        TestInterceptor testInterceptor = new TestInterceptor();
        registry.addInterceptor(testInterceptor).addPathPatterns("/**");
    }

    @Override
    public void addViewControllers(ViewControllerRegistry registry) {
        registry.addViewController("/hello").setViewName("hello");
    }
    //文件上传
//    @Bean
//    public MultipartResolver multipartResolver(){
//        CommonsMultipartResolver commonsMultipartResolver = new CommonsMultipartResolver();
//        return commonsMultipartResolver;
//    }
    //异常处理java.lang.ArithmeticException
    @Override
    public 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);
    }
}

用来替代web.xml

//web工程的初始化，用来代替web.xml
public class WebInit extends AbstractAnnotationConfigDispatcherServletInitializer {
    //spring的配置类
    @Override
    protected Class<?>[] getRootConfigClasses() {
        return new Class[]{SpringConfig.class};
    }
    //springmvc 的配置类
    @Override
    protected Class<?>[] getServletConfigClasses() {
        return new Class[]{Webconfig.class};
    }

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

    //配置过滤器
    @Override
    protected Filter[] getServletFilters() {
        CharacterEncodingFilter encodingFilter = new CharacterEncodingFilter();
        encodingFilter.setEncoding("UTF-8");
        encodingFilter.setForceResponseEncoding(true);
        HiddenHttpMethodFilter methodFilter = new HiddenHttpMethodFilter();
        return new Filter[]{encodingFilter,methodFilter};
    }
}

dispatcherservlet–关系