SpringMVC入门

一，SpringMVC简介

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

也有人声称SpringMVC
是视图层框架：原因：SpringMVC部分功能是向用户渲染展示数据
是控制层框架原因：DispatherServlet:接受浏览器端的任意请求
然后寻找对应的子控制器（适配器*Adapter）处理浏览器请求

二者皆有所理

二，helloworld实现

我们使用框架首先第一步：搭建环境

1.导入pom依赖


"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>4.0.0modelVersion>
 
    <groupId>org.examplegroupId>
    <artifactId>ssmartifactId>
    <version>1.0-SNAPSHOTversion>
    <packaging>warpackaging>
 
    <name>ssm Maven Webappname>
    
    <url>http://www.example.comurl>
 
    <properties>
        <project.build.sourceEncoding>UTF-8project.build.sourceEncoding>
        <maven.compiler.source>1.8maven.compiler.source>
        <maven.compiler.target>1.8maven.compiler.target>
        <maven.compiler.plugin.version>3.7.0maven.compiler.plugin.version>
 
        
        
        <spring.version>5.0.2.RELEASEspring.version>
        
        <mybatis.version>3.4.5mybatis.version>
        
        <mysql.version>5.1.44mysql.version>
        
        <pagehelper.version>5.1.2pagehelper.version>
        
        <mybatis.spring.version>1.3.1mybatis.spring.version>
        
        <commons.dbcp2.version>2.1.1commons.dbcp2.version>
        <commons.pool2.version>2.4.3commons.pool2.version>
        
        <log4j2.version>2.9.1log4j2.version>
        
        <junit.version>4.12junit.version>
        <servlet.version>4.0.0servlet.version>
        <lombok.version>1.18.2lombok.version>
    properties>
 
    <dependencies>
        
        <dependency>
            <groupId>org.springframeworkgroupId>
            <artifactId>spring-contextartifactId>
            <version>${spring.version}version>
        dependency>
        <dependency>
            <groupId>org.springframeworkgroupId>
            <artifactId>spring-ormartifactId>
            <version>${spring.version}version>
        dependency>
        <dependency>
            <groupId>org.springframeworkgroupId>
            <artifactId>spring-txartifactId>
            <version>${spring.version}version>
        dependency>
        <dependency>
            <groupId>org.springframeworkgroupId>
            <artifactId>spring-aspectsartifactId>
            <version>${spring.version}version>
        dependency>
        <dependency>
            <groupId>org.springframeworkgroupId>
            <artifactId>spring-webartifactId>
            <version>${spring.version}version>
        dependency>
        <dependency>
            <groupId>org.springframeworkgroupId>
            <artifactId>spring-testartifactId>
            <version>${spring.version}version>
        dependency>
 
        
        <dependency>
            <groupId>org.mybatisgroupId>
            <artifactId>mybatisartifactId>
            <version>${mybatis.version}version>
        dependency>
        
        <dependency>
            <groupId>mysqlgroupId>
            <artifactId>mysql-connector-javaartifactId>
            <version>${mysql.version}version>
        dependency>
        
        <dependency>
            <groupId>com.github.pagehelpergroupId>
            <artifactId>pagehelperartifactId>
            <version>${pagehelper.version}version>
        dependency>
        
        <dependency>
            <groupId>org.mybatisgroupId>
            <artifactId>mybatis-springartifactId>
            <version>${mybatis.spring.version}version>
        dependency>
 
        
        <dependency>
            <groupId>org.apache.commonsgroupId>
            <artifactId>commons-dbcp2artifactId>
            <version>${commons.dbcp2.version}version>
            <exclusions>
                <exclusion>
                    <artifactId>commons-pool2artifactId>
                    <groupId>org.apache.commonsgroupId>
                exclusion>
            exclusions>
        dependency>
        <dependency>
            <groupId>org.apache.commonsgroupId>
            <artifactId>commons-pool2artifactId>
            <version>${commons.pool2.version}version>
        dependency>
 
        
        
        <dependency>
            <groupId>org.apache.logging.log4jgroupId>
            <artifactId>log4j-coreartifactId>
            <version>${log4j2.version}version>
        dependency>
        <dependency>
            <groupId>org.apache.logging.log4jgroupId>
            <artifactId>log4j-apiartifactId>
            <version>${log4j2.version}version>
        dependency>
        
        <dependency>
            <groupId>org.apache.logging.log4jgroupId>
            <artifactId>log4j-webartifactId>
            <version>${log4j2.version}version>
        dependency>
 
        
        <dependency>
            <groupId>junitgroupId>
            <artifactId>junitartifactId>
            <version>${junit.version}version>
            <scope>testscope>
        dependency>
        <dependency>
            <groupId>javax.servletgroupId>
            <artifactId>javax.servlet-apiartifactId>
            <version>${servlet.version}version>
            <scope>providedscope>
        dependency>
        <dependency>
            <groupId>org.projectlombokgroupId>
            <artifactId>lombokartifactId>
            <version>${lombok.version}version>
            <scope>providedscope>
        dependency>
 
        <dependency>
            <groupId>org.springframeworkgroupId>
            <artifactId>spring-webmvcartifactId>
            <version>${spring.version}version>
        dependency>
        
        <dependency>
            <groupId>jstlgroupId>
            <artifactId>jstlartifactId>
            <version>1.2version>
        dependency>
        <dependency>
            <groupId>taglibsgroupId>
            <artifactId>standardartifactId>
            <version>1.1.2version>
        dependency>
 
    dependencies>
 
    <build>
        <finalName>ssmfinalName>
        <resources>
            
            <resource>
                <directory>src/main/javadirectory>
                <includes>
                    <include>**/*.xmlinclude>
                includes>
            resource>
            
            <resource>
                <directory>src/main/resourcesdirectory>
                <includes>
                    <include>jdbc.propertiesinclude>
                    <include>*.xmlinclude>
                includes>
            resource>
        resources>
 
        <pluginManagement>
            <plugins>
 
                <plugin>
                    <groupId>org.apache.maven.pluginsgroupId>
                    <artifactId>maven-compiler-pluginartifactId>
                    <version>${maven.compiler.plugin.version}version>
                    <configuration>
                        <source>${maven.compiler.source}source>
                        <target>${maven.compiler.target}target>
                        <encoding>${project.build.sourceEncoding}encoding>
                    configuration>
                plugin>
                <plugin>
                    <groupId>org.mybatis.generatorgroupId>
                    <artifactId>mybatis-generator-maven-pluginartifactId>
                    <version>1.3.2version>
                    <dependencies>
                        
                        <dependency>
                            <groupId>mysqlgroupId>
                            <artifactId>mysql-connector-javaartifactId>
                            <version>${mysql.version}version>
                        dependency>
                    dependencies>
                    <configuration>
                        <overwrite>trueoverwrite>
                    configuration>
                plugin>
 
                <plugin>
                    <artifactId>maven-clean-pluginartifactId>
                    <version>3.1.0version>
                plugin>
                
                <plugin>
                    <artifactId>maven-resources-pluginartifactId>
                    <version>3.0.2version>
                plugin>
                <plugin>
                    <artifactId>maven-compiler-pluginartifactId>
                    <version>3.8.0version>
                plugin>
                <plugin>
                    <artifactId>maven-surefire-pluginartifactId>
                    <version>2.22.1version>
                plugin>
                <plugin>
                    <artifactId>maven-war-pluginartifactId>
                    <version>3.2.2version>
                plugin>
                <plugin>
                    <artifactId>maven-install-pluginartifactId>
                    <version>2.5.2version>
                plugin>
                <plugin>
                    <artifactId>maven-deploy-pluginartifactId>
                    <version>2.8.2version>
                plugin>
            plugins>
        pluginManagement>
    build>
project>

缺少最下面的这两个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

2.框架配置文件


"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">
    
    
    <aop:aspectj-autoproxy/>
    <context:component-scan base-package="com.ljj.ssm"/>
 
    
    
    
    <mvc:annotation-driven>mvc:annotation-driven>
 
    
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        
        <property name="viewClass"
                  value="org.springframework.web.servlet.view.JstlView">property>
        <property name="prefix" value="/"/>
        <property name="suffix" value=".jsp"/>
    bean>
 
    
    
    
 
 
beans>

注意：此依赖为设置访问路径

3.web.xml配置核心类


<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 Applicationdisplay-name>
  <context-param>
    <param-name>contextConfigLocationparam-name>
    <param-value>classpath:applicationContext.xmlparam-value>
  context-param>
  
  <listener>
    <listener-class>org.springframework.web.context.ContextLoaderListenerlistener-class>
  listener>
 
  
  <servlet>
    <servlet-name>SpringMVCservlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServletservlet-class>
    
    <init-param>
      <param-name>contextConfigLocationparam-name>
      <param-value>/WEB-INF/springmvc-servlet.xmlparam-value>
    init-param>
    <load-on-startup>1load-on-startup>
    
    <async-supported>trueasync-supported>
  servlet>
  <servlet-mapping>
    <servlet-name>SpringMVCservlet-name>
    <url-pattern>/url-pattern>
  servlet-mapping>
web-app>

放置框架配置文件的路径

二，helloworld实现

HelloController：


package com.ljj.ssm.controller;
 
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
 
/**
 * @author ljj
 * @site www.ljj.com
 * @create 2022-08-17 2:49
 */
/*
 被controller标记的类 会交给Spring 进行管理
@Controller
@Service
@Repository
@Component
以上四个都代表 当前类 交给Spring 容器进行管理
 */
@Controller
public class HelloController {
    //  自定义mvc：  浏览器发送请求 http://localhost:8080/hello.action?methodName=hello
    //  springmvc：  浏览器发送请求 http://localhost:8080/helloReq
    @RequestMapping("/helloReq")
    public String hello(){
        System.out.println("hello springmvc...");
        return "hello";
    }
}

Hello.jsp:


<%--
  Created by IntelliJ IDEA.
  User: Administrator
  Date: 2022/8/17
  Time: 8:23
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Titletitle>
head>
<body>
Spring Mvc...你好 oyang
body>
html>

运行效果：

输入网址：

http://localhost:8080/helloReq

三、SpringMVC的工作原理

1、浏览器发送请求到中央控制器Dispatcherservlet
2、中央控制器DispatcherServlet通过处理器映射器HandlerMapping找到处理器适配器HandlerAdapter
3、执行HandlerAdapter，返回值ModelAndView回传给DispatcherServlet
4、视图解析器viewResolver会对返回值ModelAndView进行渲染，得到view视图对象
5、最后DispatcherServlet会将view视图对象返回给用户

四，CRUD及常用注解及返回值

所用的注解

Controller

Requestmapping

Requestparam


package com.ljj.ssm.controller;
 
import com.ljj.ssm.biz.BookBiz;
import com.ljj.ssm.model.Book;
import com.ljj.ssm.util.PageBean;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.*;
 
import javax.servlet.http.HttpServletRequest;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
 
/**
 * @RequestMapping 加在 类上面，称窄化路径，其实相当于包的概念
 */
@Controller
@RequestMapping("/book")
public class BookController {
    @Autowired
    private BookBiz bookBiz;
 
//    http://localhost:8080/book/list
    @RequestMapping
//    @GetMapping=@RequestMapping(value = "/list",method = RequestMethod.GET)
//    @PostMapping
//    @DeleteMapping
//    @PutMapping
    public String hello(HttpServletRequest req){
        System.out.println("hello springmvc...");
        PageBean pageBean=new PageBean();
        pageBean.setRequest(req);
        Map map=new HashMap();
        String bname = req.getParameter("bname");
        map.put("bname",bname);
        List maps = this.bookBiz.listPager(map, pageBean);
        req.setAttribute("lst",maps);
        return "hello";
    }
 
    @RequestMapping("/add")
    public String add(Book book){
        this.bookBiz.insertSelective(book);
        return "redirect:/book/list";
    }
 
    @RequestMapping("/edit")
    public String edit(Book book){
        this.bookBiz.insertSelective(book);
        return "redirect:/book/list";
    }
 
    @RequestMapping("/del/{bid}")
    public String del(@PathVariable("bid") Integer bid){
        this.bookBiz.deleteByPrimaryKey(bid);
        return "redirect:/book/list";
    }
}

index.jsp:


<%--
  Created by IntelliJ IDEA.
  User: Administrator
  Date: 2022/8/16
  Time: 21:52
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Titletitle>
head>
<body>
    <a href="${pageContext.request.contextPath}/book/list?bname=圣墟">查询所有a>
    <a href="${pageContext.request.contextPath}/book/add?bid=2&bname=sb&price=9.9">增加a>
    <a href="${pageContext.request.contextPath}/book/edit?bid=2&bname=suibian&price=9.8">修改a>
    <a href="${pageContext.request.contextPath}/book/del/2">删除a>
body>
html>

hello.jsp


<%--
  Created by IntelliJ IDEA.
  User: Administrator
  Date: 2022/8/16
  Time: 17:26
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<html>
<head>
    <title>Titletitle>
head>
<body>
SpringMVC 你好
${msg}
<hr>
${lst}
<c:forEach items="${lst}" var="l">
    ${l.bid}:${l.bname}<hr>
c:forEach>
body>
html>

点击新增后：

补充：springMvc的工作原理

1、浏览器发送请求到中央控制器Dispatcherservlet

2、中央控制器DispatcherServlet通过处理器映射器HandlerMapping找到处理器适配器HandlerAdapter

3、执行HandlerAdapter，返回值ModelAndView回传给DispatcherServlet

4、视图解析器viewResolver会对返回值ModelAndView进行渲染，得到view视图对象

5、最后DispatcherServlet会将view视图对象返回给用户

转发与重定向的设置

"hello"转发到/hello.jsp

"forward:hello" 转发到/hello.jsp

"redirect:/hello" 重定向到.../项目名/hello book/list

四、静态资源的配置

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原文地址：https://blog.csdn.net/weixin_64313980/article/details/126376676