用idea搭建SSM项目，原来这么简单

布满荆棘的人生 2021-09-19 14:06 481阅读 0赞

## **前言** ##

前阵子突发奇想，想学习下SpringMVC的源码，于是打算用idea搭建一个简易的maven版SSM案例，也就是SpringMVC+Spring+MyBatis+Maven，因为之前创建过一些Spring的小demo，相关的软件环境已经搭建完成，本以为搭建一个入门级的SSM项目应该不难，谁曾想这个过程中遇到了不少千奇百怪的问题，从开始创建到成功运行花了我整整一个下午的时间(我的午觉啊~~~·)，最后项目成功跑起来的时候我长出了一口气，为了以后不在类似的事情上折腾，特此写下这篇文章记录一下搭建过程。

## **软件环境** ##

先准备好搭建项目的基本环境

Intellij IDEA：2018.1.1

JDK：1.8

Maven：3.6.0

Tomcat：7.0及以上

下载安装好软件后，在idea软件设置里做好JDK、Maven和Tomcat的相关环境配置，这方面网上的资料很多，本文就不介绍了。

## **创建项目** ##

搭建好环境后，打开idea，点击New - Project

![1478697-20190125174000282-9497199.png][]

找到Maven一栏，因为要搭建的SpringMvc项目，所以选择webapp模板

![1478697-20190125174009844-1592708408.png][]

填写好GroupId和ArtifactId后，一步步next，最后finish完成

![1478697-20190125174016638-1922554552.png][]

创建成功后，可以看到项目是这样的目录结构

![1478697-20190125174024550-1188202458.png][]

除了配置相关依赖的pom.xml，目录中还有一个文件夹src，src的main目录提供了一个webapp文件夹，webapp文件夹下有一个WEB-INF文件夹，放置的是前端页面的文件，以及web.xml文件。

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除了模版提供的目录结构，为了后面项目能成功运行，我们还需要添加一些文件夹，让项目的目录结构变成这样：

![1478697-20190125174033046-1871917428.jpg][]

## **数据库文件** ##

首先，先准备好数据库文件，并初始化一条记录

DROP TABLE IF EXISTS `user`; CREATE TABLE `user` ( `id` int(11) NOT NULL AUTO_INCREMENT COMMENT '用户ID', `email` varchar(255) NOT NULL COMMENT '用户邮箱', `username` varchar(255) NOT NULL COMMENT '用户昵称', `role` varchar(255) NOT NULL COMMENT '用户身份', `mobile` varchar(50) DEFAULT '' COMMENT '手机号码', PRIMARY KEY (`id`) ) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf-8; -- ---------------------------- -- Records of user -- ---------------------------- INSERT INTO `user` VALUES ('1', '1589585621@qq.com', 'xjt', 'root', '15678635432');

## **配置文件** ##

### **pom.xml** ###

<?xml version="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>4.0.0</modelVersion> <groupId>com.xjt</groupId> <artifactId>mvcDemo</artifactId> <version>1.0-SNAPSHOT</version> <packaging>war</packaging> <name>mvcDemo Maven Webapp</name>  <properties> <srping.version>4.0.2.RELEASE</srping.version> <mybatis.version>3.2.8</mybatis.version> <slf4j.version>1.7.12</slf4j.version> <log4j.version>1.2.17</log4j.version> <druid.version>1.0.9</druid.version> </properties>  <dependencies>  <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>4.11</version>  <scope>test</scope> </dependency>  <dependency> <groupId>org.springframework</groupId> <artifactId>spring-test</artifactId> <version>${srping.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-core</artifactId> <version>${srping.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-oxm</artifactId> <version>${srping.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-tx</artifactId> <version>${srping.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-jdbc</artifactId> <version>${srping.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-aop</artifactId> <version>${srping.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-context</artifactId> <version>${srping.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-context-support</artifactId> <version>${srping.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-expression</artifactId> <version>${srping.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-orm</artifactId> <version>${srping.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-web</artifactId> <version>${srping.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-webmvc</artifactId> <version>${srping.version}</version> </dependency>   <dependency> <groupId>org.mybatis</groupId> <artifactId>mybatis</artifactId> <version>${mybatis.version}</version> </dependency> <dependency> <groupId>org.mybatis</groupId> <artifactId>mybatis-spring</artifactId> <version>1.2.2</version> </dependency>   <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>5.1.35</version> </dependency>  <dependency> <groupId>commons-dbcp</groupId> <artifactId>commons-dbcp</artifactId> <version>1.4</version> </dependency>  <dependency> <groupId>jstl</groupId> <artifactId>jstl</artifactId> <version>1.2</version> </dependency>  <dependency> <groupId>log4j</groupId> <artifactId>log4j</artifactId> <version>${log4j.version}</version> </dependency> <dependency> <groupId>org.slf4j</groupId> <artifactId>slf4j-api</artifactId> <version>${slf4j.version}</version> </dependency> <dependency> <groupId>org.slf4j</groupId> <artifactId>slf4j-log4j12</artifactId> <version>${slf4j.version}</version> </dependency>  <dependency> <groupId>com.alibaba</groupId> <artifactId>druid</artifactId> <version>${druid.version}</version> </dependency> </dependencies> <build>  <plugins> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-compiler-plugin</artifactId> <version>3.2</version> <configuration> <source>1.8</source> <target>1.8</target> <encoding>UTF-8</encoding> </configuration> </plugin> </plugins> </build> </project>

**注：以下四个配置文件都是放置在resources文件夹下**

### **log4j.properties** ###

#日志输出级别 log4j.rootLogger=debug,stdout,D,E #设置stdout的日志输出控制台 log4j.appender.stdout=org.apache.log4j.ConsoleAppender #输出日志到控制台的方式，默认为System.out log4j.appender.stdout.Target = System.out #设置使用灵活布局 log4j.appender.stdout.layout=org.apache.log4j.PatternLayout #灵活定义输出格式 log4j.appender.stdout.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss,SSS} -[%p] method:[%c (%rms)] - %m%n

### **jdbc.properties** ###

driver=com.mysql.jdbc.Driver url=jdbc:mysql://localhost:3306/test?characterEncoding=utf8&useSSL=false #数据库的用户名 username=root #数据库的密码，别像我一样不设置 password= #定义初始连接数 initialSize=0 #定义最大连接数 maxActive=20 #定义最大空闲 maxIdle=20 #定义最小空闲 minIdle=1 #定义最长等待时间 maxWait=60000

### **applicationContext.xml** ###

这是Spring的核心配置文件，包括Spring结合Mybatis和数据源的配置信息

<?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:tx="http://www.springframework.org/schema/tx" xmlns:context="http://www.springframework.org/schema/context" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.1.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">  <bean id="propertyConfigurer" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer"> <property name="location" value="classpath:jdbc.properties"/> </bean>  <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource"> <property name="driverClassName" value="${driver}"/> <property name="url" value="${url}"/> <property name="username" value="${username}"/> <property name="password" value="${password}"/> </bean>  <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean"> <property name="dataSource" ref="dataSource"/>  <property name="typeAliasesPackage" value="com.xjt.model"/>  <property name="mapperLocations" value="classpath:mapper/*.xml"/> </bean>  <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">  <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"/>  <property name="basePackage" value="com.xjt.dao"/> </bean>  <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">  <property name="dataSource" ref="dataSource"/> </bean>

### **spring-mvc.xml** ###

### **web.xml** ###

该文件不是放在resources，而是webapp的WEB-INF文件夹下，文件内容如下：

<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>mvcDemo</display-name>  <welcome-file-list> <welcome-file>index.jsp</welcome-file> </welcome-file-list>  <listener> <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class> </listener>  <context-param> <param-name>contextConfigLocation</param-name> <param-value>classpath:applicationContext.xml</param-value> </context-param>  <filter> <filter-name>CharacterEncodingFilter</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> <init-param> <param-name>forceEncoding</param-name> <param-value>true</param-value> </init-param> </filter> <filter-mapping> <filter-name>CharacterEncodingFilter</filter-name> <url-pattern>/*</url-pattern> </filter-mapping>  <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:spring-mvc.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>

## **运行项目** ##

上面的配置文件编写好之后，其实我们就可以尝试着启动项目了，**启动项目前先把applicationContext.xml的内容都注释了**，然后就可以创建运行环境了。

点击idea右上角的 Edit Configurations...

![1478697-20190125174056515-2131620806.png][]

选择Tomcat Server - Local，

![1478697-20190125174104250-875981092.png][]

编辑好项目的启动信息，包括项目名，jdk版本，tomcat以及端口

![1478697-20190125174111103-637103790.png][]

选择Deployment，添加Atifact，选择第二项，否则Tomcat运行会报错

![1478697-20190125174118500-1275540393.png][]

保存后，启动项目，成功后在浏览器输入[http://localhost:8080][http_localhost_8080]，返回结果如下：  
![1478697-20190125174126925-589621201.png][]

这是index.jsp文件中的内容，因为index.jsp是启动页，所以项目启动后返回的结果是启动页的内容

<html> <body> <h2>Hello World!</h2> </body> </html>

## **编写代码** ##

项目能跑起来，说明我们前端控制器的配置是成功的，接下来要做的是测试能否访问数据库。首先，把基本的类文件创建并编写好代码。

**实体类：User.java**

package com.xjt.model; public class User { private long id; private String email; private String mobile; private String username; private String role; public long getId() { return id; } public void setId(long id) { this.id = id; } public String getEmail() { return email; } public void setEmail(String email) { this.email = email; } public String getMobile() { return mobile; } public void setMobile(String mobile) { this.mobile = mobile; } public String getUsername() { return username; } public void setUsername(String username) { this.username = username; } public String getRole() { return role; } public void setRole(String role) { this.role = role; } }

**dao文件：IUserDao**

package com.xjt.dao; import com.xjt.model.User; public interface IUserDao { User selectUser(long id); }

**mapper文件：UserDao.xml**

位于resources - mapper文件夹下

<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">  <mapper namespace="com.xjt.dao.IUserDao"> <select id="selectUser" resultType="User" parameterType="long"> SELECT * FROM user WHERE id = #{id} </select> </mapper>

**service接口：IUserService**

package com.xjt.service; import com.xjt.model.User; public interface IUserService { public User selectUser(long userId); }

**UserServiceImpl**

package com.xjt.service.impl; import com.xjt.dao.IUserDao; import com.xjt.model.User; import com.xjt.service.IUserService; import org.springframework.stereotype.Service; import javax.annotation.Resource; @Service("userService") public class UserServiceImpl implements IUserService { @Resource private IUserDao userDao; public User selectUser(long userId) { return userDao.selectUser(userId); } }

**controller文件：UserController**

package com.xjt.controller; import com.xjt.model.User; import com.xjt.service.IUserService; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Controller; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.servlet.ModelAndView; @Controller @RequestMapping("/user") public class UserController { @Autowired private IUserService userService; @RequestMapping("/select") public ModelAndView selectUser() throws Exception { ModelAndView mv = new ModelAndView(); User user = userService.selectUser(1); mv.addObject("user", user); mv.setViewName("user"); return mv; } }

UserController定义了一个方法`selectUser`，读取id为1的User信息，并返回user.jsp页面，访问的路径是/user/select，user.jsp位于 WEB-INF 的 jsp 文件夹下，代码如下：

<%@ page contentType="text/html;charset=UTF-8" language="java" %> <html> <head> <title>user</title> </head> <body> id:${requestScope.user.id}<br/> email:${requestScope.user.email}<br/> username:${requestScope.user.username}<br/> role:${requestScope.user.role}<br/> mobile:${requestScope.user.mobile}<br/> </body> </html>

都编写完毕以后，撤销applicationContext.xml文件的注释符号，然后开启项目，成功后在浏览器输入[http://localhost:8080/user/select][http_localhost_8080_user_select]

![1478697-20190125174457654-1191439004.png][]

页面成功的返回了User信息，说明，我们成功访问到了数据库的内容。

至此，SSM项目的搭建大功告成，为了方便大家学习，我把源码放在了github上了，有需要的同学可以自行下载，地址：[https://github.com/Taoxj/mvcDemo][https_github.com_Taoxj_mvcDemo]

[1478697-20190125174000282-9497199.png]: /images/20210812/bd988242ca7a42ee970ac029eeb193b2.png
[1478697-20190125174009844-1592708408.png]: /images/20210812/8f81f706382f4aada41743cd3e97f4a3.png
[1478697-20190125174016638-1922554552.png]: /images/20210812/47a39f715ed748b7814b5b1c5f0a4106.png
[1478697-20190125174024550-1188202458.png]: /images/20210812/14f82736a1d94b019186be619698eddd.png
[1478697-20190125174033046-1871917428.jpg]: /images/20210812/26b3ecada4df4a8290e0052a86a4fd2f.png
[1478697-20190125174056515-2131620806.png]: /images/20210812/be59219dbc194b6196a0de468c3d7666.png
[1478697-20190125174104250-875981092.png]: /images/20210812/f572846f146e4f7d8d0c416bf973d483.png
[1478697-20190125174111103-637103790.png]: /images/20210812/58074d9b0aba433ca830740b9468360b.png
[1478697-20190125174118500-1275540393.png]: /images/20210812/3e33fa76f0f847ec928141085a4bec5b.png
[http_localhost_8080]: http://localhost:8080/
[1478697-20190125174126925-589621201.png]: /images/20210812/ec791c0896c947f88e5b612f2c5180e3.png
[http_localhost_8080_user_select]: http://localhost:8080/user/select
[1478697-20190125174457654-1191439004.png]: /images/20210812/cebd77d4d9e64708b6d120cd3f1d9874.png
[https_github.com_Taoxj_mvcDemo]: https://github.com/Taoxj/mvcDemo