SpringMVC框架详解-优快云博客

本文链接：https://blog.youkuaiyun.com/weixin_43939301/article/details/102411844

目标
1、Springmvc简介及配置
2、Springmvc之helloword实现
3、Springmvc常用注解及返回值处理
4、Springmvc静态资源处理

Springmvc简介及配置

什么是springMVC?
Spring Web MVC是一种基于Java的实现了MVC设计模式的、请求驱动类型的、轻量级Web框架。
SpringMVC处理请求的流程
2.1 首先用户发送请求–>DispatherServlet
2.2 DispatcherServlet–>HandlerMapping
2.3 DispatcherServlet–>HandlerAdapter
2.4 HandlerAdapter–>处理器功能处理方法的调用
2.5 ModelAndView的逻辑视图名–>ViewRecolver
2.6 View–>渲染
2.7 返回控制权给DispatcherServlet，由DispatcherServlet返回呼应给用户，流程结束
SpringMVC核心开发步骤
3.1 DispatcherServlet在web.xml中的部署描述，从而拦截请求到springMVC
3.2 HandlerMapping的配置，从而将请求映射到处理器
3.3 HandlerAdapter的配置，从而支持多种类型的处理器
3.4 处理器(页面控制器)的配置，从而刊行功能处理
3.5 ViewResolver的配置，从而将逻辑视图名解析为具体的视图技术
SpringMVC的组件
4.1 前端控制器(DispatcherServlet)
4.2 请求到处理器映射(HandlerMapping)
4.3 处理器适配器(HandlerAdapter)
4.4 视图解析器(ViewResolver)
4.5 处理器或页面控制器(Controller)
4.6 验证器(Validator)
4.6 命令对象(Command 请求参数绑定到的对象就叫命令对象)
4.7 表单对象(Form Object提供给表单展示和提交到的对象就叫表单对象)
如何在项目中添加springmvc
5.1 添加相关依赖

 <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-webmvc</artifactId>
        <version>${spring.version}</version>
      </dependency>

– ********************** JSTL依赖 ********************** –
– 缺少下面的这两个jar包会报java.lang.NoClassDefFoundError: javax/servlet/jsp/jstl/core/Config–
– 原因：org.springframework.web.servlet.view.JstlView在视图解析时需要这二个jar包–

<dependency>
          <groupId>jstl</groupId>
          <artifactId>jstl</artifactId>
          <version>1.2</version>
      </dependency>
      <dependency>
          <groupId>taglibs</groupId>
          <artifactId>standard</artifactId>
          <version>1.1.2</version>
      </dependency>

5.2 在WEB-INF下添加springmvc-servlet.xml(spring-mvc.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" xmlns:aop="http://www.springframework.org/schema/aop"
       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-4.3.xsd http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd">
    <!-- 通过context:component-scan元素扫描指定包下的控制器-->
    <!--1) 扫描com.javaxl.zf及子子孙孙包下的控制器(扫描范围过大，耗时)-->
    <aop:aspectj-autoproxy/>
    <context:component-scan base-package="com.javaxl.ssm"/>

    <!--2) 此标签默认注册DefaultAnnotationHandlerMapping和AnnotationMethodHandlerAdapter -->
    <!--两个bean，这两个bean是spring MVC为@Controllers分发请求所必须的。并提供了数据绑定支持，-->
    <!--@NumberFormatannotation支持，@DateTimeFormat支持，@Valid支持，读写XML的支持（JAXB），读写JSON的支持（Jackson）-->
    <mvc:annotation-driven></mvc:annotation-driven>

    <!--3) ViewResolver -->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <!-- viewClass需要在pom中引入两个包：standard.jar and jstl.jar -->
        <property name="viewClass"
                  value="org.springframework.web.servlet.view.JstlView"></property>
        <property name="prefix" value="/"/>
        <property name="suffix" value=".jsp"/>
    </bean>

    <!--4) 单独处理图片、样式、js等资源 -->
    <!--<mvc:resources location="/css/" mapping="/css/**"/>-->
    <mvc:resources location="/images/" mapping="/images/**"/>
    <!--<mvc:resources location="/js/" mapping="/js/**"/>-->


</beans>

5.3 修改web.xml

<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_3_1.xsd"
         version="3.1">
  <display-name>Archetype Created Web Application</display-name>
  <context-param>
    <param-name>contextConfigLocation</param-name>
    <param-value>classpath:applicationContext.xml</param-value>
  </context-param>
  <!-- 读取Spring上下文的监听器 -->
  <listener>
    <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
  </listener>

  <!-- Spring MVC servlet -->
  <servlet>
    <servlet-name>SpringMVC</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <!--此参数可以不配置，默认值为：/WEB-INF/springmvc-servlet.xml-->
    <init-param>
      <param-name>contextConfigLocation</param-name>
      <param-value>/WEB-INF/spring-mvc.xml</param-value>
    </init-param>
    <load-on-startup>1</load-on-startup>
    <!--web.xml 3.0的新特性，是否支持异步-->
    <async-supported>true</async-supported>
  </servlet>
  <servlet-mapping>
    <servlet-name>SpringMVC</servlet-name>
    <url-pattern>/</url-pattern>
  </servlet-mapping>
</web-app>

Springmvc之helloword实现
6. 第一个springMVC程序：HelloWorld

package com.ly.controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

import javax.servlet.http.HttpServletRequest;

/**
 * @author 毅哥哥
 * @site
 * @company
 * @create 2019-09-28 11:44
 *
 * 关于结果集处理分五种情况
 * 1、转发到页面
 * 2、转发到action请求
 * 3、重定向到页面
 * 4、重定向到action
 */
@Controller
public class HelloController {
    @RequestMapping("hello")
    public String hello(HttpServletRequest request){
        request.setAttribute("msg","转发到页面的方式");
        return "hello";
    }

    /**
     * 重定向到action中
     * @param request
     * @return
     */
    @RequestMapping("hello2")
    public String redirectPage(HttpServletRequest request){
        request.setAttribute("msg","重定向到action的方式");
        return "redirect:hello";
    }

    /**
     * 重定向到页面
     * @param request
     * @return
     */
    @RequestMapping("hello3")
    public String redirectPage2(HttpServletRequest request){
        Object msg = request.getAttribute("msg");
        return "redirect:/hello.jsp";
    }

    @RequestMapping("hello4")
    public String forwardAction(HttpServletRequest request){
        request.setAttribute("msg","重定向到action的方式");
        return "forward:hello3";
    }

    @RequestMapping("hello5")
    public String forwardAction2(HttpServletRequest request){
        request.setAttribute("msg","转发访问安全页面");
        return "sb";
    }
}

Springmvc常用注解及返回值处理
通过crud进行讲解
Controller
Requestmapping
Requestparam
传参

package com.ly.controller;

import com.ly.model.Book;
import com.ly.service.BookService;
import com.ly.util.PageBean;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;

import javax.servlet.http.HttpServletRequest;
import java.util.List;
import java.util.Map;

/**
 * @author 毅哥哥
 * @site
 * @company
 * @create 2019-10-08 20:08
 */
@Controller
@RequestMapping("/book")
public class BookController {
    @Autowired
    private BookService bookService;

    @RequestMapping("/list")
    public String list(HttpServletRequest request, Book book){
        PageBean pageBean = new PageBean();
        pageBean.setRequest(request);
        List<Map> list = this.bookService.listPager(book, pageBean);
        System.out.println(pageBean.getRows());
        System.out.println(pageBean.getTotal());
        request.setAttribute("bookList",list);
        request.setAttribute("pageBean",pageBean);
        return "bookList";
    }

    @RequestMapping("/preSave")
    public String preSave(Book book,HttpServletRequest request){
        if(book.getBid() != null){
            Book b = this.bookService.selectByPrimaryKey(book.getBid());
            request.setAttribute("b",b);
        }

        return "bookEdit";
    }

    @RequestMapping("/add")
    public String add(Book book,HttpServletRequest request){
        this.bookService.insert(book);
        return "redirect:/book/list";
    }

    @RequestMapping("/del/{bid}")
    public String del(@PathVariable(value = "bid") Integer bid, HttpServletRequest request){
        this.bookService.deleteByPrimaryKey(bid);
        return "redirect:/book/list";
    }

    @RequestMapping("/edit")
    public String edit(Book book,HttpServletRequest request){
        this.bookService.updateByPrimaryKeySelective(book);
        return "redirect:/book/list";
    }
}