spring+SpringMVC+MyBatis（SSM）在我们项目中是经常用到的，这篇文章主要讲解使用Intellij IDEA整合SSM，具体环境如下：

数据库：MySQL5.7
依赖管理：Maven
IDE：Intellij IDEA
JDK：1.8
服务器：Tomcat 9

首先用Intellij IDEA创建Maven项目，如果还不知道怎么创建的朋友可以先去百度谷歌，网上很多这种教程，这里我主要讲解SSM整合的过程，项目目录结构如下：
这里写图片描述

1.创建表，插入数据

CREATE TABLE user (
  id       INTEGER PRIMARY KEY AUTO_INCREMENT,
  name     CHAR(20) NOT NULL,
  password CHAR(40) NOT NULL
)
  ENGINE = InnoDB
  AUTO_INCREMENT = 16
  DEFAULT CHARSET = utf8;

INSERT INTO user (id,name, password) VALUES (1,'A', '123');
INSERT INTO user (id,name, password) VALUES (2,'B', '456');

2.添加Maven依赖

<?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.demo</groupId>
    <artifactId>SSM</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>war</packaging>
    <name>SSM</name>
    <description/>

    <properties>
        <spring.version>4.3.4.RELEASE</spring.version>
        <mybatis.version>3.4.2</mybatis.version>
        <log4j.version>2.7</log4j.version>
        <junit.version>4.12</junit.version>
        <driver.version>5.1.40</driver.version>
    </properties>

    <dependencies>
        <!--Spring start-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>${spring.version}</version>
        </dependency>

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

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

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

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

        <!--绑定XML-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-oxm</artifactId>
            <version>${spring.version}</version>
        </dependency>

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

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

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-aspects</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <!--Spring end-->

        <!--AOP start-->
        <dependency>
            <groupId>aopalliance</groupId>
            <artifactId>aopalliance</artifactId>
            <version>1.0</version>
        </dependency>

        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjweaver</artifactId>
            <version>1.8.10</version>
        </dependency>
        <!--AOP end-->

        <!--文件上传start-->
        <dependency>
            <groupId>commons-fileupload</groupId>
            <artifactId>commons-fileupload</artifactId>
            <version>1.3.2</version>
        </dependency>
        <!--文件上传end-->

        <!--json start-->
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-core</artifactId>
            <version>2.8.4</version>
        </dependency>

        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.8.4</version>
        </dependency>
        <!--json end-->

        <!--mybatis start-->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.4.2</version>
        </dependency>

        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis-spring</artifactId>
            <version>1.3.1</version>
        </dependency>
        <!--mybatis end-->

        <!--log start-->
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-core</artifactId>
            <version>${log4j.version}</version>
        </dependency>
        <!--log end-->

        <!--单元测试start-->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>${junit.version}</version>
        </dependency>
        <!--单元测试end-->

        <!--数据库驱动start-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.40</version>
        </dependency>
        <!--数据库驱动end-->

        <!--druid start-->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.0.29</version>
        </dependency>
        <!--druid end-->
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.6.1</version>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>

            <!--MBG-->
            <plugin>
                <groupId>org.mybatis.generator</groupId>
                <artifactId>mybatis-generator-maven-plugin</artifactId>
                <version>1.3.5</version>
                <configuration>
                    <verbose>true</verbose>
                    <overwrite>true</overwrite>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>

代码都加了注释，很容易看懂。需要说一下的是MBG，全称是MyBatis Generator，是一个生成MyBatis代码的插件，后面会用到。具体可以看看 MyBatis Generator官方文档

3.配置文件

3.1 Mybatis配置文件mybatis-config.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>

</configuration>

3.2 数据库配置文件database.properties

db.driver=com.mysql.jdbc.Driver
db.url=jdbc:mysql://localhost:3306/mybatis?characterEncoding=UTF-8
db.user=root
db.password=123456
db.maxActive=10
db.initialSize=2
db.minIdle=2
db.maxWait=60000
db.timeBetweenEvictionRunsMillis=3000
db.minEvictableIdleTimeMillis=300000
db.validationQuery=SELECT 'x' FROM DUAL
db.testWhileIdle=true
db.testOnBorrow=false
db.testOnReturn=false

3.3 Spring配置文件application.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">

    <import resource="classpath:spring/spring-mybatis.xml"/>

</beans>

这里为了方便项目扩展，用import标签引入另一个配置文件spring-mybatis.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: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.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">

    <context:property-placeholder location="classpath:properties/database.properties"/>

    <!--数据源配置-->
    <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource" init-method="init" destroy-method="close">
        <!--驱动-->
        <property name="driverClassName" value="${db.driver}"/>
        <!-- 数据库地址 -->
        <property name="url" value="${db.url}"/>
        <!-- 用户名 -->
        <property name="username" value="${db.user}"/>
        <!-- 密码 -->
        <property name="password" value="${db.password}"/>
        <!-- 最大连接池数量 -->
        <property name="maxActive" value="${db.maxActive}"/>
        <!-- 初始化物理连接个数 -->
        <property name="initialSize" value="${db.initialSize}"/>
        <!-- 最小连接池数量 -->
        <property name="minIdle" value="${db.minIdle}"/>
        <!-- 最大等待时间 -->
        <property name="maxWait" value="${db.maxWait}"/>
        <property name="timeBetweenEvictionRunsMillis" value="${db.timeBetweenEvictionRunsMillis}"/>
        <property name="minEvictableIdleTimeMillis" value="${db.minEvictableIdleTimeMillis}"/>
        <!-- 检测连接是否有效的SQL -->
        <property name="validationQuery" value="${db.validationQuery}"/>
        <property name="testWhileIdle" value="${db.testWhileIdle}"/>
        <!-- 申请连接时是否执行validationQuery -->
        <property name="testOnBorrow" value="${db.testOnBorrow}"/>
        <!-- 归还连接时是否执行validationQuery -->
        <property name="testOnReturn" value="${db.testOnReturn}"/>
    </bean>

    <!-- 配置Mybatis的文件 ，mapperLocations配置**Mapper.xml文件位置，configLocation配置mybatis-config文件位置-->
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource"/>
        <property name="mapperLocations" value="classpath:mapper/*.xml"/>
        <property name="configLocation" value="classpath:mybatis/mybatis-config.xml"/>
    </bean>

    <!-- 自动扫描了所有的XxxxMapper.xml对应的mapper接口文件，这样就不用一个一个手动配置Mpper的映射了，
           只要Mapper接口类和Mapper映射文件对应起来就可以了 -->
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <property name="basePackage" value="com.demo.dao"/>
        <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"/>
    </bean>

    <!-- 事物管理器 -->
    <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <property name="dataSource" ref="dataSource"/>
    </bean>

    <tx:annotation-driven transaction-manager="transactionManager"/>
</beans>

3.4 SpringMVC配置文件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:mvc="http://www.springframework.org/schema/mvc"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">

    <!-- 注解的支持，可以将请求参数绑定到控制器参数-->
    <mvc:annotation-driven/>

    <!--注解扫描-->
    <context:component-scan base-package="com.demo.controller"/>
    <context:component-scan base-package="com.demo.serviceImpl"/>

    <!--静态资源处理，mapping：匹配URL，location：静态资源在WebApp中的位置-->
    <mvc:resources mapping="/common/**" location="/common/"/>
    <mvc:resources mapping="/css/**" location="/css/"/>
    <mvc:resources mapping="/image/**" location="/image/"/>
    <mvc:resources mapping="/js/**" location="/js/"/>

    <!-- 注解的映射器 -->
    <bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping"/>

    <!-- 注解的适配器 -->
    <bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter"/>

    <!-- 视图解析器 -->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="contentType" value="text/html"/>
        <property name="prefix" value="/jsp/"/>
        <property name="suffix" value=".jsp"/>
    </bean>

    <!--上传文件配置-->
    <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
        <!-- 默认编码 -->
        <property name="defaultEncoding" value="UTF-8"/>
        <!-- 启用是为了推迟文件解析，以便捕获文件大小异常 -->
        <property name="resolveLazily" value="true"/>
        <!-- 文件大小最大值 -->
        <property name="maxUploadSize" value="209715200"/>
        <!-- 内存中的最大值 -->
        <property name="maxInMemorySize" value="40960"/>
    </bean>

</beans>

3.5 log4j配置文件log4j.xml

<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="WARN">
    <Appenders>
        <Console name="Console" target="SYSTEM_OUT">
            <PatternLayout pattern="%d{HH:mm:ss.SSS} [%t] %-5level %logger{36} - %msg%n" />
        </Console>
    </Appenders>
    <Loggers>
        <Root level="debug">
            <AppenderRef ref="Console" />
        </Root>
    </Loggers>
</Configuration>

3.6 MyBatis Generator配置文件generatorConfig.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE generatorConfiguration
        PUBLIC "-//mybatis.org//DTD MyBatis Generator Configuration 1.0//EN"
        "http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd">

<generatorConfiguration>
    <!--数据库驱动-->
    <classPathEntry
            location="C:/Users/Administrator/.m2/repository/mysql/mysql-connector-java/5.1.40/mysql-connector-java-5.1.40.jar"/>

    <context id="mybatis" targetRuntime="MyBatis3">
        <!-- 防止生成的代码中有很多注释-->
        <commentGenerator>
            <property name="suppressAllComments" value="true"/>
            <property name="suppressDate" value="true"/>
        </commentGenerator>

        <jdbcConnection driverClass="com.mysql.jdbc.Driver"
                        connectionURL="jdbc:mysql://localhost:3306/mybatis"
                        userId="root"
                        password="199498xy">
        </jdbcConnection>

        <!--Java类型解析器不应该强制型对象字段BigDecimal的使用，此功能是为了使数据库DECIMAL和NUMERIC列容易处理-->
        <javaTypeResolver>
            <property name="forceBigDecimals" value="false"/>
        </javaTypeResolver>

        <!--生成Model类存放位置-->
        <javaModelGenerator targetPackage="com.demo.bean" targetProject="E:/workspace/java/project/SSM/src/main/java">
            <property name="enableSubPackages" value="true"/>
            <property name="trimStrings" value="true"/>
        </javaModelGenerator>

        <!--生成映射文件存放位置-->
        <sqlMapGenerator targetPackage="mapper" targetProject="E:/workspace/java/project/SSM/src/main/resources">
            <property name="enableSubPackages" value="true"/>
        </sqlMapGenerator>

        <!--生成Dao类存放位置-->
        <javaClientGenerator type="XMLMAPPER" targetPackage="com.demo.dao" targetProject="E:/workspace/java/project/SSM/src/main/java">
            <property name="enableSubPackages" value="true"/>
        </javaClientGenerator>

        <!--生成对应表及类名-->
        <table tableName="user" domainObjectName="User"/>

    </context>
</generatorConfiguration>

命令行运行maven命令

mvn mybatis-generator:generate

生成User表的Mapper.xml文件、bean和对应的接口，bean和接口下面会说到

<?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.demo.dao.UserMapper">
  <resultMap id="BaseResultMap" type="com.demo.bean.User">
    <id column="id" jdbcType="INTEGER" property="id" />
    <result column="name" jdbcType="CHAR" property="name" />
    <result column="password" jdbcType="CHAR" property="password" />
  </resultMap>
  <sql id="Example_Where_Clause">
    <where>
      <foreach collection="oredCriteria" item="criteria" separator="or">
        <if test="criteria.valid">
          <trim prefix="(" prefixOverrides="and" suffix=")">
            <foreach collection="criteria.criteria" item="criterion">
              <choose>
                <when test="criterion.noValue">
                  and ${criterion.condition}
                </when>
                <when test="criterion.singleValue">
                  and ${criterion.condition} #{criterion.value}
                </when>
                <when test="criterion.betweenValue">
                  and ${criterion.condition} #{criterion.value} and #{criterion.secondValue}
                </when>
                <when test="criterion.listValue">
                  and ${criterion.condition}
                  <foreach close=")" collection="criterion.value" item="listItem" open="(" separator=",">
                    #{listItem}
                  </foreach>
                </when>
              </choose>
            </foreach>
          </trim>
        </if>
      </foreach>
    </where>
  </sql>
  <sql id="Update_By_Example_Where_Clause">
    <where>
      <foreach collection="example.oredCriteria" item="criteria" separator="or">
        <if test="criteria.valid">
          <trim prefix="(" prefixOverrides="and" suffix=")">
            <foreach collection="criteria.criteria" item="criterion">
              <choose>
                <when test="criterion.noValue">
                  and ${criterion.condition}
                </when>
                <when test="criterion.singleValue">
                  and ${criterion.condition} #{criterion.value}
                </when>
                <when test="criterion.betweenValue">
                  and ${criterion.condition} #{criterion.value} and #{criterion.secondValue}
                </when>
                <when test="criterion.listValue">
                  and ${criterion.condition}
                  <foreach close=")" collection="criterion.value" item="listItem" open="(" separator=",">
                    #{listItem}
                  </foreach>
                </when>
              </choose>
            </foreach>
          </trim>
        </if>
      </foreach>
    </where>
  </sql>
  <sql id="Base_Column_List">
    id, name, password
  </sql>
  <select id="selectByExample" parameterType="com.demo.bean.UserExample" resultMap="BaseResultMap">
    select
    <if test="distinct">
      distinct
    </if>
    <include refid="Base_Column_List" />
    from user
    <if test="_parameter != null">
      <include refid="Example_Where_Clause" />
    </if>
    <if test="orderByClause != null">
      order by ${orderByClause}
    </if>
  </select>
  <select id="selectByPrimaryKey" parameterType="java.lang.Integer" resultMap="BaseResultMap">
    select 
    <include refid="Base_Column_List" />
    from user
    where id = #{id,jdbcType=INTEGER}
  </select>
  <delete id="deleteByPrimaryKey" parameterType="java.lang.Integer">
    delete from user
    where id = #{id,jdbcType=INTEGER}
  </delete>
  <delete id="deleteByExample" parameterType="com.demo.bean.UserExample">
    delete from user
    <if test="_parameter != null">
      <include refid="Example_Where_Clause" />
    </if>
  </delete>
  <insert id="insert" parameterType="com.demo.bean.User">
    insert into user (id, name, password)
    values (#{id,jdbcType=INTEGER}, #{name,jdbcType=CHAR}, #{password,jdbcType=CHAR})
  </insert>
  <insert id="insertSelective" parameterType="com.demo.bean.User">
    insert into user
    <trim prefix="(" suffix=")" suffixOverrides=",">
      <if test="id != null">
        id,
      </if>
      <if test="name != null">
        name,
      </if>
      <if test="password != null">
        password,
      </if>
    </trim>
    <trim prefix="values (" suffix=")" suffixOverrides=",">
      <if test="id != null">
        #{id,jdbcType=INTEGER},
      </if>
      <if test="name != null">
        #{name,jdbcType=CHAR},
      </if>
      <if test="password != null">
        #{password,jdbcType=CHAR},
      </if>
    </trim>
  </insert>
  <select id="countByExample" parameterType="com.demo.bean.UserExample" resultType="java.lang.Long">
    select count(*) from user
    <if test="_parameter != null">
      <include refid="Example_Where_Clause" />
    </if>
  </select>
  <update id="updateByExampleSelective" parameterType="map">
    update user
    <set>
      <if test="record.id != null">
        id = #{record.id,jdbcType=INTEGER},
      </if>
      <if test="record.name != null">
        name = #{record.name,jdbcType=CHAR},
      </if>
      <if test="record.password != null">
        password = #{record.password,jdbcType=CHAR},
      </if>
    </set>
    <if test="_parameter != null">
      <include refid="Update_By_Example_Where_Clause" />
    </if>
  </update>
  <update id="updateByExample" parameterType="map">
    update user
    set id = #{record.id,jdbcType=INTEGER},
      name = #{record.name,jdbcType=CHAR},
      password = #{record.password,jdbcType=CHAR}
    <if test="_parameter != null">
      <include refid="Update_By_Example_Where_Clause" />
    </if>
  </update>
  <update id="updateByPrimaryKeySelective" parameterType="com.demo.bean.User">
    update user
    <set>
      <if test="name != null">
        name = #{name,jdbcType=CHAR},
      </if>
      <if test="password != null">
        password = #{password,jdbcType=CHAR},
      </if>
    </set>
    where id = #{id,jdbcType=INTEGER}
  </update>
  <update id="updateByPrimaryKey" parameterType="com.demo.bean.User">
    update user
    set name = #{name,jdbcType=CHAR},
      password = #{password,jdbcType=CHAR}
    where id = #{id,jdbcType=INTEGER}
  </update>
</mapper>

3.7 web配置文件web.xml

<?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">

    <!-- 起始欢迎界面 -->
    <welcome-file-list>
        <welcome-file>index.jsp</welcome-file>
    </welcome-file-list>

    <!-- 错误跳转页面 -->
    <error-page>
        <!-- 路径不正确 -->
        <error-code>404</error-code>
        <location>/error/404.jsp</location>
    </error-page>

    <error-page>
        <!-- 没有访问权限，访问被禁止 -->
        <error-code>405</error-code>
        <location>/error/405.jsp</location>
    </error-page>

    <error-page>
        <!-- 内部错误 -->
        <error-code>500</error-code>
        <location>/error/500.jsp</location>
    </error-page>

    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>classpath:application.xml</param-value>
    </context-param>

    <!-- Spring字符集过滤器 -->
    <filter>
        <filter-name>SpringEncodingFilter</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>SpringEncodingFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>

    <servlet>
        <servlet-name>dispatcher</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:spring/spring-mvc.xml</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>

    <servlet-mapping>
        <servlet-name>dispatcher</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>

</web-app>

4.接口和类

4.1 com.demo.bean下的User.java和UserExample.java

这两个类是由MBG生成的

package com.demo.bean;

public class User {
    private Integer id;

    private String name;

    private String password;

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name == null ? null : name.trim();
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password == null ? null : password.trim();
    }
}

Example类用于构造复杂的筛选条件

package com.demo.bean;

import java.util.ArrayList;
import java.util.List;

public class UserExample {
    protected String orderByClause;

    protected boolean distinct;

    protected List<Criteria> oredCriteria;

    public UserExample() {
        oredCriteria = new ArrayList<Criteria>();
    }

    public void setOrderByClause(String orderByClause) {
        this.orderByClause = orderByClause;
    }

    public String getOrderByClause() {
        return orderByClause;
    }

    public void setDistinct(boolean distinct) {
        this.distinct = distinct;
    }

    public boolean isDistinct() {
        return distinct;
    }

    public List<Criteria> getOredCriteria() {
        return oredCriteria;
    }

    public void or(Criteria criteria) {
        oredCriteria.add(criteria);
    }

    public Criteria or() {
        Criteria criteria = createCriteriaInternal();
        oredCriteria.add(criteria);
        return criteria;
    }

    public Criteria createCriteria() {
        Criteria criteria = createCriteriaInternal();
        if (oredCriteria.size() == 0) {
            oredCriteria.add(criteria);
        }
        return criteria;
    }

    protected Criteria createCriteriaInternal() {
        Criteria criteria = new Criteria();
        return criteria;
    }

    public void clear() {
        oredCriteria.clear();
        orderByClause = null;
        distinct = false;
    }

    protected abstract static class GeneratedCriteria {
        protected List<Criterion> criteria;

        protected GeneratedCriteria() {
            super();
            criteria = new ArrayList<Criterion>();
        }

        public boolean isValid() {
            return criteria.size() > 0;
        }

        public List<Criterion> getAllCriteria() {
            return criteria;
        }

        public List<Criterion> getCriteria() {
            return criteria;
        }

        protected void addCriterion(String condition) {
            if (condition == null) {
                throw new RuntimeException("Value for condition cannot be null");
            }
            criteria.add(new Criterion(condition));
        }

        protected void addCriterion(String condition, Object value, String property) {
            if (value == null) {
                throw new RuntimeException("Value for " + property + " cannot be null");
            }
            criteria.add(new Criterion(condition, value));
        }

        protected void addCriterion(String condition, Object value1, Object value2, String property) {
            if (value1 == null || value2 == null) {
                throw new RuntimeException("Between values for " + property + " cannot be null");
            }
            criteria.add(new Criterion(condition, value1, value2));
        }

        public Criteria andIdIsNull() {
            addCriterion("id is null");
            return (Criteria) this;
        }

        public Criteria andIdIsNotNull() {
            addCriterion("id is not null");
            return (Criteria) this;
        }

        public Criteria andIdEqualTo(Integer value) {
            addCriterion("id =", value, "id");
            return (Criteria) this;
        }

        public Criteria andIdNotEqualTo(Integer value) {
            addCriterion("id <>", value, "id");
            return (Criteria) this;
        }

        public Criteria andIdGreaterThan(Integer value) {
            addCriterion("id >", value, "id");
            return (Criteria) this;
        }

        public Criteria andIdGreaterThanOrEqualTo(Integer value) {
            addCriterion("id >=", value, "id");
            return (Criteria) this;
        }

        public Criteria andIdLessThan(Integer value) {
            addCriterion("id <", value, "id");
            return (Criteria) this;
        }

        public Criteria andIdLessThanOrEqualTo(Integer value) {
            addCriterion("id <=", value, "id");
            return (Criteria) this;
        }

        public Criteria andIdIn(List<Integer> values) {
            addCriterion("id in", values, "id");
            return (Criteria) this;
        }

        public Criteria andIdNotIn(List<Integer> values) {
            addCriterion("id not in", values, "id");
            return (Criteria) this;
        }

        public Criteria andIdBetween(Integer value1, Integer value2) {
            addCriterion("id between", value1, value2, "id");
            return (Criteria) this;
        }

        public Criteria andIdNotBetween(Integer value1, Integer value2) {
            addCriterion("id not between", value1, value2, "id");
            return (Criteria) this;
        }

        public Criteria andNameIsNull() {
            addCriterion("name is null");
            return (Criteria) this;
        }

        public Criteria andNameIsNotNull() {
            addCriterion("name is not null");
            return (Criteria) this;
        }

        public Criteria andNameEqualTo(String value) {
            addCriterion("name =", value, "name");
            return (Criteria) this;
        }

        public Criteria andNameNotEqualTo(String value) {
            addCriterion("name <>", value, "name");
            return (Criteria) this;
        }

        public Criteria andNameGreaterThan(String value) {
            addCriterion("name >", value, "name");
            return (Criteria) this;
        }

        public Criteria andNameGreaterThanOrEqualTo(String value) {
            addCriterion("name >=", value, "name");
            return (Criteria) this;
        }

        public Criteria andNameLessThan(String value) {
            addCriterion("name <", value, "name");
            return (Criteria) this;
        }

        public Criteria andNameLessThanOrEqualTo(String value) {
            addCriterion("name <=", value, "name");
            return (Criteria) this;
        }

        public Criteria andNameLike(String value) {
            addCriterion("name like", value, "name");
            return (Criteria) this;
        }

        public Criteria andNameNotLike(String value) {
            addCriterion("name not like", value, "name");
            return (Criteria) this;
        }

        public Criteria andNameIn(List<String> values) {
            addCriterion("name in", values, "name");
            return (Criteria) this;
        }

        public Criteria andNameNotIn(List<String> values) {
            addCriterion("name not in", values, "name");
            return (Criteria) this;
        }

        public Criteria andNameBetween(String value1, String value2) {
            addCriterion("name between", value1, value2, "name");
            return (Criteria) this;
        }

        public Criteria andNameNotBetween(String value1, String value2) {
            addCriterion("name not between", value1, value2, "name");
            return (Criteria) this;
        }

        public Criteria andPasswordIsNull() {
            addCriterion("password is null");
            return (Criteria) this;
        }

        public Criteria andPasswordIsNotNull() {
            addCriterion("password is not null");
            return (Criteria) this;
        }

        public Criteria andPasswordEqualTo(String value) {
            addCriterion("password =", value, "password");
            return (Criteria) this;
        }

        public Criteria andPasswordNotEqualTo(String value) {
            addCriterion("password <>", value, "password");
            return (Criteria) this;
        }

        public Criteria andPasswordGreaterThan(String value) {
            addCriterion("password >", value, "password");
            return (Criteria) this;
        }

        public Criteria andPasswordGreaterThanOrEqualTo(String value) {
            addCriterion("password >=", value, "password");
            return (Criteria) this;
        }

        public Criteria andPasswordLessThan(String value) {
            addCriterion("password <", value, "password");
            return (Criteria) this;
        }

        public Criteria andPasswordLessThanOrEqualTo(String value) {
            addCriterion("password <=", value, "password");
            return (Criteria) this;
        }

        public Criteria andPasswordLike(String value) {
            addCriterion("password like", value, "password");
            return (Criteria) this;
        }

        public Criteria andPasswordNotLike(String value) {
            addCriterion("password not like", value, "password");
            return (Criteria) this;
        }

        public Criteria andPasswordIn(List<String> values) {
            addCriterion("password in", values, "password");
            return (Criteria) this;
        }

        public Criteria andPasswordNotIn(List<String> values) {
            addCriterion("password not in", values, "password");
            return (Criteria) this;
        }

        public Criteria andPasswordBetween(String value1, String value2) {
            addCriterion("password between", value1, value2, "password");
            return (Criteria) this;
        }

        public Criteria andPasswordNotBetween(String value1, String value2) {
            addCriterion("password not between", value1, value2, "password");
            return (Criteria) this;
        }
    }

    public static class Criteria extends GeneratedCriteria {

        protected Criteria() {
            super();
        }
    }

    public static class Criterion {
        private String condition;

        private Object value;

        private Object secondValue;

        private boolean noValue;

        private boolean singleValue;

        private boolean betweenValue;

        private boolean listValue;

        private String typeHandler;

        public String getCondition() {
            return condition;
        }

        public Object getValue() {
            return value;
        }

        public Object getSecondValue() {
            return secondValue;
        }

        public boolean isNoValue() {
            return noValue;
        }

        public boolean isSingleValue() {
            return singleValue;
        }

        public boolean isBetweenValue() {
            return betweenValue;
        }

        public boolean isListValue() {
            return listValue;
        }

        public String getTypeHandler() {
            return typeHandler;
        }

        protected Criterion(String condition) {
            super();
            this.condition = condition;
            this.typeHandler = null;
            this.noValue = true;
        }

        protected Criterion(String condition, Object value, String typeHandler) {
            super();
            this.condition = condition;
            this.value = value;
            this.typeHandler = typeHandler;
            if (value instanceof List<?>) {
                this.listValue = true;
            } else {
                this.singleValue = true;
            }
        }

        protected Criterion(String condition, Object value) {
            this(condition, value, null);
        }

        protected Criterion(String condition, Object value, Object secondValue, String typeHandler) {
            super();
            this.condition = condition;
            this.value = value;
            this.secondValue = secondValue;
            this.typeHandler = typeHandler;
            this.betweenValue = true;
        }

        protected Criterion(String condition, Object value, Object secondValue) {
            this(condition, value, secondValue, null);
        }
    }
}

4.2 com.demo.dao下的UserMapper.java

这个DAO也是MBG生成的，这下体会到MBG的好处了吧，一下子帮你生成了这么多代码，年轻人可以少熬点夜了~

package com.demo.dao;

import com.demo.bean.User;
import com.demo.bean.UserExample;
import java.util.List;
import org.apache.ibatis.annotations.Param;

public interface UserMapper {
    long countByExample(UserExample example);

    int deleteByExample(UserExample example);

    int deleteByPrimaryKey(Integer id);

    int insert(User record);

    int insertSelective(User record);

    List<User> selectByExample(UserExample example);

    User selectByPrimaryKey(Integer id);

    int updateByExampleSelective(@Param("record") User record, @Param("example") UserExample example);

    int updateByExample(@Param("record") User record, @Param("example") UserExample example);

    int updateByPrimaryKeySelective(User record);

    int updateByPrimaryKey(User record);
}

4.3 com.demo.service下的UserService.java接口

这里只定义了简单的增删查改方法

package com.demo.service;

import com.demo.bean.User;

import java.util.List;

public interface UserService {

    void insertUser(User user);

    void deleteUser(int id);

    User findUserById(Integer id);

    List<User> findAllUsers();

    void updateUser(User user);
}

4.4 com.demo.serviceImpl下的UserServiceImpl.java

UserServiceImpl实现了UserService，通过注入UserMapper 对数据进行操作

package com.demo.serviceImpl;

import com.demo.bean.User;
import com.demo.bean.UserExample;
import com.demo.dao.UserMapper;
import com.demo.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

@Service
public class UserServiceImpl implements UserService {

    @Autowired
    private UserMapper userMapper;

    @Override
    public void insertUser(User user) {
        userMapper.insert(user);
    }

    @Override
    public void deleteUser(int id) {
        UserExample userExample = new UserExample();
        userExample.createCriteria().andIdEqualTo(id);
        userMapper.deleteByExample(userExample);
    }

    @Override
    public User findUserById(Integer id) {
        return userMapper.selectByPrimaryKey(id);
    }

    @Override
    public List<User> findAllUsers() {
        return userMapper.selectByExample(null);
    }

    @Override
    public void updateUser(User user) {
        userMapper.updateByPrimaryKey(user);
    }

}

4.5 com.demo.controller下的UserController.java

MVC模式下的控制器，通过注入的UserService完成相关业务

package com.demo.controller;

import com.demo.bean.User;
import com.demo.service.UserService;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
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 org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;

@Controller
@RequestMapping(value = "/user")
public class UserController {

    private static Logger logger = LogManager.getLogger();

    @Autowired
    private UserService userService;

    @RequestMapping(value = "/{id}", method = RequestMethod.GET)
    @ResponseBody
    public User findUserById(@PathVariable("id") Integer id) {
        User user = userService.findUserById(id);
        logger.info(user.toString());
        return user;
    }
}

5.测试

将项目部署到本地的Tomcat上，打开你的chrome，访问：

http://localhost:8080/user/1

浏览器访问服务器，服务器成功返回一个json数据

这里写图片描述

ok，到这里我们整个SSM整合过程已经完成，后面只要在这个基础上开发就可以了。github项目地址，欢迎star和fork~