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SSM框架---SpringMVC

2021-04-03 21:36:22   25  举报

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springMVC

SSM

作者其他创作

大纲/内容

回顾servlet

1、创建父项目

2、导入maven依赖

3、创建子模块

4、添加框架支持

5、子模块导入maven依赖

6、web.xml配置servlet

7、编写servlet测试类

1、继承HttpServlet类

2、重写doGet和doPost方法

1、获取前端参数

String method = req.getParameter("method");

2、调用业务层

3、视图转发

req.getRequestDispatcher("/WEB-INF/jsp/test.jsp").forward(req,resp);

8、在web.xml中注册servlet

    <servlet>
        <servlet-name>hello</servlet-name>
        <servlet-class>com.learning.servlet.HelloServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>hello</servlet-name>
        <url-pattern>/hello</url-pattern>
    </servlet-mapping>

9、配置tomcat

配置一个SpringMVC

基础版

1、创建子模块，添加web支持

2、导入springmvc依赖

3、配置web.xml，注册DispatcherServlet

4、编写springmvc-servlet.xml

1、添加处理器映射器

BeanNameUrlHandlerMapping

2、添加处理器适配器

SimpleControllerHandlerAdapter

3、添加视图解析器

InternalResourceViewResolver

5、编写业务controller

6、把类交给SpringIOC容器，注册bean

7、编写需要跳转的页面

8、如果报错404，需要建立lib目录，添加jar包

9、如果报错500，去把lib中的老版本的jsp，servletjar包删除

注解版

1、创建子模块、添加web支持

2、在web.xml中注册springmvc

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

3、新建springmvc-servlet.xml文件

如果文件出错，打开setting、editor、file type、text、找到不对劲的名字，删除

<?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">

    <!--spring自动扫描-->
    <context:component-scan base-package="com.learning.controller"/>
    <!--让springmvc不处理静态资源-->
    <mvc:default-servlet-handler/>
    <!--springmvc注解驱动
        实现这个后不需要再手动注册handlerMapping和handlerAdapter
        annotation-driven会帮我们自动注入-->
    <mvc:annotation-driven/>

    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" id="internalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/jsp/"/>
        <property name="suffix" value=".jsp"/>
    </bean>

</beans>

4、创建controller

/**
 * @author 22944
 */
@Controller
@RequestMapping("/hello")
public class HelloAnnotationController {

    @RequestMapping("/h1")
    public String h1(Model model){
        model.addAttribute("msg","你好啊");
        return "hello";
    }

}

一个请求的执行过程

1、前端发送请求

2、servlet通过路径映射进入springmvc

    <servlet>
        <servlet-name>springmvc</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:springmvc-servlet.xml</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>

    <servlet-mapping>
        <servlet-name>springmvc</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>

3、springmvc找到handleMapping

4、handleMapping找到对应的control返回给前端控制器，前端控制器再通过处理器适配器找到对应的controller

5、处理业务逻辑

6、返回一个ModelView给前端控制器

7、前端控制器转发给视图解析器，添加前缀后缀，找到对应的jsp页面，返回给前端控制器

8、前端控制器把返回的jsp返回给用户

SpringMVC的乱码过滤器

<filter>
        <filter-name>encoding</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>
    </filter>
    <filter-mapping>
        <filter-name>encoding</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

json交互

1、新建子模块、添加web支持

2、maven导入jackson-databind依赖

3、注册DispatcherServlet

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

4、编写springmvc-servlet

<!-- 自动扫描指定的包，下面所有注解类交给IOC容器管理 -->
        <context:component-scan base-package="com.learning.controller"/>

        <!-- 视图解析器 -->
        <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"
        id="internalResourceViewResolver">
        <!-- 前缀 -->
            <property name="prefix" value="/WEB-INF/jsp/" />
            <!-- 后缀 -->
            <property name="suffix" value=".jsp" />
        </bean>

5、注册过滤器

        <filter>
            <filter-name>encoding</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>
        </filter>
        <filter-mapping>
            <filter-name>encoding</filter-name>
            <url-pattern>/</url-pattern>
        </filter-mapping>

6、编写Controller

7、乱码统一解决

    <mvc:annotation-driven>
        <mvc:message-converters register-defaults="true">
            <bean class="org.springframework.http.converter.StringHttpMessageConverter">
                <constructor-arg value="UTF-8"/>
            </bean>
            <bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
                <property name="objectMapper">
                    <bean class="org.springframework.http.converter.json.Jackson2ObjectMapperFactoryBean">
                        <property name="failOnEmptyBeans" value="false"/>
                    </bean>
                </property>
            </bean>
        </mvc:message-converters>
    </mvc:annotation-driven>

SpringMVC拦截器

拦截器是aop思想的体现

1、编写web.xml

1、注册DispatcherServlet

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

2、配置过滤器

    <!--配置过滤器-->
    <filter>
        <filter-name>encoding</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>
    </filter>
    <filter-mapping>
        <filter-name>encoding</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

2、编写applicationContext.xml

1、添加注解支持

    <!--注解驱动-->
    <mvc:annotation-driven/>

2、自动扫描controller包

<!--配置自动扫描controller-->
<context:component-scan base-package="com.learning.controller"/>

3、配置静态资源过滤

<!--配置静态资源过滤-->
<mvc:default-servlet-handler/>

4、配置视图解析器

    <!--视图解析器-->
    <bean id="internalResourceViewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/jsp/"/>
        <property name="suffix" value=".jsp"/>
    </bean>

5、配置拦截器

    <mvc:interceptors>
        <mvc:interceptor>
            <mvc:mapping path="/**"/>
            <bean class="com.learning.config.MyInterceptor"/>
        </mvc:interceptor>
        
    </mvc:interceptors>

3、编写controller类

1、新建config包

2、编写拦截器类

实现HandlerInterceptor接口，实现方法

文件示例

package com.learning.config;

import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * @author 小也
 * @create 2021/4/2 22:11
 */
public class MyInterceptor implements HandlerInterceptor {
    /**
     * return true  放行，执行下一个拦截器
     * return false 拦截，不执行下一个拦截器
     */

    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        System.out.println("=========方法执行前=========");
        return false;
    }

    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        System.out.println("=========方法执行后=========");
    }

    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        System.out.println("=========清理=========");
    }
}