用idea搭建SSM框架maven项目

打开idea，点击New - Project

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

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

创建成功后，可以看到项目是这样的目录结构

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。

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：

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 ('', '1589585621@qq.com', 'xjt', 'root', '');

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>

  <!-- 用来设置版本号 -->
  <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>
  <!-- 用到的jar包 -->
  <dependencies>
    <!-- 单元测试 -->
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.11</version>
      <!-- 表示开发的时候引入，发布的时候不会加载此包 -->
      <scope>test</scope>
    </dependency>

    <!-- spring框架包 -->
    <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>
    <!-- spring框架包 -->
    <!-- mybatis框架包 -->
    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis</artifactId>
      <version>${mybatis.version}</version>
    </dependency>
    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis-spring</artifactId>
      <version>1.2.2</version>
    </dependency>
    <!-- mybatis框架包 -->
    <!-- 数据库驱动 -->
    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>5.1.35</version>
    </dependency>
    <!-- 导入dbcp的jar包，用来在applicationContext.xml中配置数据库 -->
    <dependency>
      <groupId>commons-dbcp</groupId>
      <artifactId>commons-dbcp</artifactId>
      <version>1.4</version>
    </dependency>
    <!-- jstl标签类 -->
    <dependency>
      <groupId>jstl</groupId>
      <artifactId>jstl</artifactId>
      <version>1.2</version>
    </dependency>
    <!-- log -->
    <dependency>
      <groupId>log4j</groupId>
      <artifactId>log4j</artifactId>
      <version>${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>
    <!-- 连接池 -->
    <dependency>
      <groupId>com.alibaba</groupId>
      <artifactId>druid</artifactId>
      <version>${druid.version}</version>
    </dependency>
  </dependencies>

  <build>
    <finalName>mvcDemo</finalName>

    <!-- java编译插件,如果maven的设置里配置好jdk版本就不用 -->
    <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>

      <plugin>
        <groupId>org.apache.tomcat.maven</groupId>
        <artifactId>tomcat7-maven-plugin</artifactId>
        <version>2.2</version>
        <configuration>
          <port>8080</port>
          <path>/${build.finalName}</path>
          <uriEncoding>UTF-8</uriEncoding>
          <server>tomcat7</server>
        </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

延伸知识

idea+maven配置log4j详解    我在搭建log4j日志时特意看啦下  可略过

第一步，在pom.xml中加入相关依赖：

<!-- 添加log4j日志相关jar包:共3个jar-->
        <!-- https://mvnrepository.com/artifact/log4j/log4j -->
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.slf4j/slf4j-api -->
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
            <version>1.7.25</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.slf4j/slf4j-log4j12 -->
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-log4j12</artifactId>
            <version>1.7.25</version>
            <scope>test</scope>
        </dependency>

第二步，在项目的 src/test/resource目录下新建log4j.properties文件，文件内容为：

### set log levels ###
log4j.rootLogger = debug,stdout,R 

### console appender###
log4j.appender.stdout = org.apache.log4j.ConsoleAppender
log4j.appender.stdout.Target = System.out
log4j.appender.stdout.Threshold = Info
log4j.appender.stdout.layout = org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern = %d [%t] %p [%c] - %m%n

### output to files ###
log4j.appender.R = org.apache.log4j.DailyRollingFileAppender
log4j.appender.R.File = logs/log.txt
log4j.appender.R.Append = true
log4j.appender.R.Threshold = Info
log4j.appender.R.layout = org.apache.log4j.PatternLayout
#log4j.appender.R.layout.ConversionPattern = %-d{yyyy-MM-dd HH:mm:ss}-[%p]%m%n
log4j.appender.R.layout.ConversionPattern = %d [%t] %p [%c] - %m%n

第三步，编写测试代码

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class Log4jTest {
    public static void main(String[] args) {
        Logger LOG = LoggerFactory.getLogger(Log4jTest.class);
        LOG.info("开始记录日志...");
        LOG.info("循环打印0到10之间的整数");
        for(int i=0;i<;i++) {
            System.out.println(i);
        }
        LOG.info("结束日志!");
    }
}

以上关于log4j解说，请往下 看

jdbc.properties

driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/mvcDemo?characterEncoding=utf8&useSSL=false
#数据库的用户名
username=root
#数据库的密码
password=123456
#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">

    <!-- 加载properties文件 -->
    <bean id="propertyConfigurer" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
        <property name="location" value="classpath:jdbc.properties"/>
    </bean>

    <!-- 配置数据源 -->
    <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>

    <!-- mybatis和spring完美整合，不需要mybatis的配置映射文件 -->
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource"/>
        <!-- 扫描model包 -->
        <property name="typeAliasesPackage" value="com.xjt.model"/>
        <!-- 扫描sql配置文件:mapper需要的xml文件 -->
        <property name="mapperLocations" value="classpath:mapper/*.xml"/>
    </bean>

    <!-- Mapper动态代理开发，扫描dao接口包-->
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <!-- 注入sqlSessionFactory -->
        <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"/>
        <!-- 给出需要扫描Dao接口包 -->
        <property name="basePackage" value="com.xjt.dao"/>
    </bean>

    <!-- 事务管理 -->
    <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <!--数据库连接池-->
        <property name="dataSource" ref="dataSource"/>
    </bean>

</beans>

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"
       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">

    <!-- 扫描注解，这样com.xjt包下的文件都能被扫描 -->
    <context:component-scan base-package="com.xjt"/>

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

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

    <!-- 配置返回视图的路径，以及识别后缀是jsp文件 -->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="viewClass" value="org.springframework.web.servlet.view.JstlView"/>
        <property name="prefix" value="/WEB-INF/jsp/"/>
        <property name="suffix" value=".jsp"/>
    </bean>
</beans>

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>
  <!--项目的欢迎页，项目运行起来后访问的页面-->
  <welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>

  <!-- 注册ServletContext监听器，创建容器对象，并且将ApplicationContext对象放到Application域中 -->
  <listener>
    <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
  </listener>

  <!-- 指定spring核心配置文件 -->
  <context-param>
    <param-name>contextConfigLocation</param-name>
    <param-value>classpath:applicationContext.xml</param-value>
  </context-param>

  <!-- 解决乱码的过滤器 -->
  <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>

  <!-- 配置前端控制器 -->
  <servlet>
    <servlet-name>springmvc</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <!-- 指定配置文件位置和名称 如果不设置,默认找/WEB-INF/<servlet-name>-servlet.xml -->
    <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>

index.jsp文件

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

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">

<!-- 设置为IUserDao接口方法提供sql语句配置 -->
<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>

在浏览器输入http://localhost:8080，返回结果如下：

在浏览器输入http://localhost:8080/user/select

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。

中途遇到的错误

Tomcat启动Exception invoking method manageApp

<finalName>LXWSEM</finalName>

<plugin>
<groupId>org.apache.tomcat.maven</groupId>
<artifactId>tomcat7-maven-plugin</artifactId>
<version>2.2</version>
<configuration>
<port>8080</port>
<path>/${build.finalName}</path>
<uriEncoding>UTF-8</uriEncoding>
<server>tomcat7</server>
</configuration>
</plugin>

java.sql.SQLException: Access denied for user 'root     '@'localhost' (using password: YES)

url=jdbc:mysql://localhost:3306/mvcDemo?characterEncoding=utf8&useSSL=false

数据库是mvcDemo

启动内置tomcat

jar包35个

借鉴：https://www.cnblogs.com/yeya/p/10320885.html