用idea和maven编写spring项目

2020-08-31

记录下用idea新建Spring项目

0x01 环境配置

Jdk
Tomcat
maven

0x02 简单的hello world

新建一个项目

给项目命名

选择maven，这里settings.xml必须要和repository在同一个目录，否则会出错，setting.xml可以添加阿里云的仓库

<?xml version="1.0" encoding="UTF-8"?>
<settings xmlns="http://maven.apache.org/SETTINGS/1.0.0" 
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
    xsi:schemaLocation="http://maven.apache.org/SETTINGS/1.0.0 http://maven.apache.org/xsd/settings-1.0.0.xsd">
    
    <pluginGroups />
    <proxies />
    <servers />
    
    <!-- maven自动下载的jar包，会存放到该目录下 -->
<localRepository>C:\Users\admin\software\Maven\repository</localRepository>    
    <mirrors>
        <mirror>
            <id>alimaven</id>
            <mirrorOf>central</mirrorOf>
            <name>aliyun maven</name>
            <url>http://maven.aliyun.com/nexus/content/repositories/central/</url>
        </mirror>
        <mirror>
            <id>alimaven</id>
            <name>aliyun maven</name>
            <url>http://maven.aliyun.com/nexus/content/groups/public/</url>
            <mirrorOf>central</mirrorOf>
        </mirror>
        <mirror>
            <id>central</id>
            <name>Maven Repository Switchboard</name>
            <url>http://repo1.maven.org/maven2/</url>
            <mirrorOf>central</mirrorOf>
        </mirror>
        <mirror>
            <id>repo2</id>
            <mirrorOf>central</mirrorOf>
            <name>Human Readable Name for this Mirror.</name>
            <url>http://repo2.maven.org/maven2/</url>
        </mirror>
        <mirror>
            <id>ibiblio</id>
            <mirrorOf>central</mirrorOf>
            <name>Human Readable Name for this Mirror.</name>
            <url>http://mirrors.ibiblio.org/pub/mirrors/maven2/</url>
        </mirror>
        <mirror>
            <id>jboss-public-repository-group</id>
            <mirrorOf>central</mirrorOf>
            <name>JBoss Public Repository Group</name>
            <url>http://repository.jboss.org/nexus/content/groups/public</url>
        </mirror>
        <mirror>
            <id>google-maven-central</id>
            <name>Google Maven Central</name>
            <url>https://maven-central.storage.googleapis.com
            </url>
            <mirrorOf>central</mirrorOf>
        </mirror>
        <!-- 中央仓库在中国的镜像 -->
        <mirror>
            <id>maven.net.cn</id>
            <name>oneof the central mirrors in china</name>
            <url>http://maven.net.cn/content/groups/public/</url>
            <mirrorOf>central</mirrorOf>
        </mirror>
    </mirrors>
    
</settings>

新建完项目的目录结构是这样的

然后添加java和resources文件夹

配置Tomcat，

点击运行。

可以修改应用上下文为/

即可以在htp://localhost:8081访问到hello world

0x03 导入Spring MVC

编辑pom.xml，添加spring

<!-- https://mvnrepository.com/artifact/org.springframework/spring-beans -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-beans</artifactId>
      <version>5.1.17.RELEASE</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/org.springframework/spring-context -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-context</artifactId>
      <version>5.1.17.RELEASE</version>
    </dependency>

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-context-support</artifactId>
      <version>5.1.17.RELEASE</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-core</artifactId>
      <version>5.1.17.RELEASE</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-expression</artifactId>
      <version>5.1.17.RELEASE</version>
    </dependency>

    <!-- 可选模块，按需添加 -->
    <!-- AOP -->
    <!-- 基于代理的AOP支持 -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-aop</artifactId>
      <version>5.1.17.RELEASE</version>
    </dependency>
    <!-- 提供与AspectJ的集成 -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-aspects</artifactId>
      <version>5.1.17.RELEASE</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/org.springframework/spring-web -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-web</artifactId>
      <version>5.1.17.RELEASE</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/org.springframework/spring-webmvc -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-webmvc</artifactId>
      <version>5.1.17.RELEASE</version>
    </dependency>
    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>jstl</artifactId>
      <version>1.2</version>
    </dependency>

在<dependencies>标签中添加上面的依赖，在选择包的时候可以利用https://mvnrepository.com/这个网站搜索复制指定版本的pom.xml文件内容。

添加框架支持，默认的web.xml是

<!DOCTYPE web-app PUBLIC
 "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
 "http://java.sun.com/dtd/web-app_2_3.dtd" >

<web-app>
  <display-name>Archetype Created Web Application</display-name>
</web-app>

当Add Frameworks Support之后，这里选择5.1.17.RELEASE版本的spring（如果没有Spring，在Project Structure中将Spring去掉就可以了）

会新生成applicationContext.xml、springMVC-servlet.xml两个文件。(不同的spring版本生成的servlet配置文件名不一定相同)

0x04 配置 springMVC 之 xml 配置

默认生成的两个xml文件如下：

applicationContext.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"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">

</beans>

springMVC-servlet.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"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">

</beans>

在web.xml中加入下面的标签配置springMVC-servlet.xml作为mvc的配置文件

<?xml version="1.0" encoding="UTF-8"?>
<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>/WEB-INF/applicationContext.xml</param-value>
  </context-param>
  <listener>
    <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
  </listener>
  <!--welcome pages-->
  <welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>

  <!--配置springmvc DispatcherServlet-->
  <servlet>
    <servlet-name>springMVC</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <init-param>
      <!--配置dispatcher.xml作为mvc的配置文件-->
      <param-name>contextConfigLocation</param-name>
      <param-value>/WEB-INF/springMVC-servlet.xml</param-value>
    </init-param>
    <load-on-startup>1</load-on-startup>
    <async-supported>true</async-supported>
  </servlet>

  <servlet-mapping>
    <servlet-name>springMVC</servlet-name>
    <url-pattern>/</url-pattern>
  </servlet-mapping>
</web-app>

编辑springMVC-servlet.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"
       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.xsd
       http://www.springframework.org/schema/mvc
       http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd">

    <!-- 扫描web相关的bean -->
    <context:component-scan base-package="com.mount4in"/>

    <!-- 开启SpringMVC注解模式 -->
    <mvc:annotation-driven/>

    <!-- 静态资源默认servlet配置 -->
    <mvc:default-servlet-handler/>

    <!-- 配置jsp 显示ViewResolver -->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="viewClass" value="org.springframework.web.servlet.view.JstlView"/>
        <property name="prefix" value="/WEB-INF/views/"/>
        <property name="suffix" value=".jsp"/>
    </bean>
</beans>

在java文件夹新建package:com.mount4in.controller，之后新建IndexController.java文件,如下所示：

运行程序：

0x05 配置springMVC之Java配置

新建com.mounti4n.config包，新建WebXml、ApplicationContextXml和DispatcherServletXml类分别代替web.xml、application-context.xml和dispather-servlet.xml，

//WebXml.java
package com.mount4in.config;

import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;

public class WebXml extends AbstractAnnotationConfigDispatcherServletInitializer{
    @Override
    protected Class<?>[] getRootConfigClasses() {
        return new Class<?>[] {ApplicationContextXml.class};
    }

    /*
        <!--配置springmvc DispatcherServlet-->
        <servlet>
            <servlet-name>springMVC</servlet-name>
            <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
            <init-param>
                <!--配置dispatcher.xml作为mvc的配置文件-->
                <param-name>contextConfigLocation</param-name>
                <param-value>/WEB-INF/dispatcher-servlet.xml</param-value>
            </init-param>
            <load-on-startup>1</load-on-startup>
            <async-supported>true</async-supported>
        </servlet>
     */
    @Override
    protected Class<?>[] getServletConfigClasses() {
        return new Class<?>[] {DispatcherServletXml.class};
    }

    /*
        <servlet-mapping>
            <servlet-name>springMVC</servlet-name>
            <url-pattern>/</url-pattern>
        </servlet-mapping>
     */
    @Override
    protected String[] getServletMappings() {
        return new String[] {"/"};
    }
}

//ApplicationContextXml.java
package com.mount4in.config;

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.FilterType;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;

@Configuration
/*
    <context:component-scan base-package="com.mount4in"/>
*/
@ComponentScan(basePackages = {"com.mount4in"},
        excludeFilters = {
                @ComponentScan.Filter(type = FilterType.ANNOTATION, value = EnableWebMvc.class)
        })

public class ApplicationContextXml {
}

//DispatcherServletXml.java
package com.mount4in.config;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.ViewResolver;
import org.springframework.web.servlet.config.annotation.*;
import org.springframework.web.servlet.view.InternalResourceViewResolver;

@Configuration
@EnableWebMvc
/*
    <!-- 自动扫描装配 -->
    <context:component-scan base-package="com.mount4in.controller"/>
*/
@ComponentScan("com.mount4in.controller")

    public class DispatcherServletXml implements WebMvcConfigurer {
        /*
            <!-- 对模型视图名称的解析，即在模型视图名称添加前后缀(如果最后一个还是表示文件夹,则最后的斜杠不要漏了) 使用JSP-->
            <!-- 默认的视图解析器 在上边的解析错误时使用 (默认使用html)- -->
            <bean id="defaultViewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
                <property name="viewClass" value="org.springframework.web.servlet.view.JstlView"/>
                <property name="prefix" value="/WEB-INF/views/"/><!--设置JSP文件的目录位置-->
                <property name="suffix" value=".jsp"/>
                <property name="exposeContextBeansAsAttributes" value="true"/>
            </bean>
         */
        @Bean
        public ViewResolver viewResolver() {
            InternalResourceViewResolver resolver = new InternalResourceViewResolver();
            resolver.setViewClass(org.springframework.web.servlet.view.JstlView.class);
            resolver.setPrefix("/WEB-INF/views/");
            resolver.setSuffix(".jsp");
            resolver.setExposeContextBeansAsAttributes(true);
            return resolver;
        }

        @Override
        public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) {
            configurer.enable();
        }
        // 静态资源配置
    /*
        <mvc:resources mapping="css/**" location="/WEB-INF/views/css/"/>
        <mvc:resources mapping="/js/**" location="/WEB-INF/views/js/"/>
        <mvc:resources mapping="/images/**" location="/WEB-INF/views/images/"/>
     */
        @Override
        public void addResourceHandlers(ResourceHandlerRegistry registry) {
            registry.addResourceHandler("/css/**").addResourceLocations("/WEB-INF/views/css/");
            registry.addResourceHandler("/js/**").addResourceLocations("/WEB-INF/views/js/");
            registry.addResourceHandler("/images/**").addResourceLocations("/WEB-INF/views/images/");
        }
    }

运行，

坑点：

tomcat控制台乱码问题：修改tomcat的/conf目录的logging.properties下图中指示位置为GBK。
报错严重 [RMI TCP Connection(3)-127.0.0.1] org.apache.tomcat.util.modeler.BaseModelMBean.invoke Exception
1. 地址忘了加“/”
- 你的业务处理层Servlet注解
- 你使用web.xml写的url-pattern
1. 你编译过项目后生成了target文件夹（存放你的项目字节码文件），你又修改了项目某文件名或类名，重启Tomcat就会发生这种情况。删除target文件夹，在重启Tomcat即可。
  （我的情况，自己修改了个实体类名称，导致类加载无法找到）
参考

参考：

IntelliJ IDEA 搭建SpringMVC并用MAVEN配置

IntelliJ IDEA上创建Maven Spring MVC项目

【从无到有】IDEA + maven + java web + springMVC + Tomcat 项目搭建

作者: Mount4in
文章链接: http://mount4in.github.io/2020/08/31/用idea和maven编写spring项目/
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