前言:

spring+springmvc+mybatis，称为ssm。ssm可以说是后端程序员必备技能，应该也是目前用得最多的，所以无论如何都要掌握！下面一起来看整合案例。点我下载源码。
开发环境:
1、开发工具:eclipse 4.7.3
2、maven 3.5.2
3、jdk 1.9
4、tomcat 8.5
5、mysql 5.7.21

一、项目环境搭建:

1、创建项目:
打开eclipse，file --> new --> maven project --> maven archetype webapp，然后填写好artifactId，点finish即可。若是创建maven项目失败，请参考eclipse创建maven项目失败解决方法
2、创建项目目录结构:
创建好项目以后，按照下图创建项目结构:

注意:项目刚创建出来可能只有src/main/java，自己创建其他的时候是 new source folder，而不是package。
3、添加依赖:
接下来就是添加依赖，本案例需要如下依赖:

<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/maven-v4_0_0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.zhu</groupId>
    <artifactId>ssm</artifactId>
    <packaging>war</packaging>
    <version>0.0.1-SNAPSHOT</version>
    <name>ssm Maven Webapp</name>
    <url>http://maven.apache.org</url>
    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
            <scope>test</scope>
        </dependency>


        <!-- https://mvnrepository.com/artifact/org.springframework/spring-core -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>4.3.14.RELEASE</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.springframework/spring-beans -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-beans</artifactId>
            <version>4.3.14.RELEASE</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.springframework/spring-context -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>4.3.14.RELEASE</version>
        </dependency>


        <!-- https://mvnrepository.com/artifact/org.springframework/spring-jdbc -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>4.3.14.RELEASE</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.springframework/spring-tx -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-tx</artifactId>
            <version>4.3.14.RELEASE</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.springframework/spring-web -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-web</artifactId>
            <version>4.3.14.RELEASE</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.springframework/spring-webmvc -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>4.3.14.RELEASE</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.springframework/spring-test -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-test</artifactId>
            <version>4.3.14.RELEASE</version>
            <scope>test</scope>
        </dependency>

        <!-- https://mvnrepository.com/artifact/javax.servlet/javax.servlet-api -->
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>3.1.0</version>
            <scope>provided</scope>
        </dependency>

        <!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-databind -->
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.8.7</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/commons-collections/commons-collections -->
        <dependency>
            <groupId>commons-collections</groupId>
            <artifactId>commons-collections</artifactId>
            <version>3.2</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.mybatis/mybatis -->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.4.2</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.mybatis/mybatis-spring -->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis-spring</artifactId>
            <version>1.3.1</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.37</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/com.mchange/c3p0 -->
        <dependency>
            <groupId>com.mchange</groupId>
            <artifactId>c3p0</artifactId>
            <version>0.9.5.2</version>
        </dependency>


>>  </dependencies>
    <build>
        <finalName>ssm</finalName>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <version>3.6.1</version>
            </plugin>
        </plugins>
    </build>
</project>

4、完成各项配置:
添加好依赖之后，就来完成jdbc数据源、mybatis和spring 的配置:

jdbc.properties

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql:///ssm?useUnicode=true&characterEncoding=utf8
jdbc.username=#
jdbc.password=#

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>
    <!-- 配置全局属性 -->
    <settings>
        <!-- 使用jdbc的getGeneratedKeys获取数据库自增主键值 -->
        <setting name="useGeneratedKeys" value="true" />

        <!-- 使用列别名替换列名 -->
        <!-- <setting name="useColumnLabel" value="true"/> -->

        <!-- 开启驼峰命名转换(userId === user_id) -->
        <setting name="mapUnderscoreToCamelCase" value="true" />
    </settings>

    <!-- 取别名，比如一个方法中返回值类型是User，
             配置了这个在 parameterType属性中就不用写User的全类名，
            直接写User即可，可以在这里配置，也可以再spring配置文件中配置 -->
    <!-- <typeAliases> <package name="com.zhu.smm.entity"/> </typeAliases> -->

</configuration>

src/main/resource/spring下有如下三个配置文件，分别配置dao层，service层，controller层:
spring-dao.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:p="http://www.springframework.org/schema/p"  
    xmlns:aop="http://www.springframework.org/schema/aop"   
    xmlns:context="http://www.springframework.org/schema/context"  
    xmlns:jee="http://www.springframework.org/schema/jee"  
    xmlns:tx="http://www.springframework.org/schema/tx"  
    xsi:schemaLocation="    
        http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.0.xsd  
        http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd  
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd  
        http://www.springframework.org/schema/jee http://www.springframework.org/schema/jee/spring-jee-4.0.xsd  
        http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd">    
        
    <!-- 配置整合mybatis过程 -->
    
    <!-- 1、配置数据库相关参数properties的属性：${url} -->
    <context:property-placeholder location="classpath:jdbc.properties" />
    
    <!-- 2、配置数据库连接池 -->
    <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <!-- 配置连接池属性 -->
        <property name="driverClass" value="${jdbc.driver}"/>
        <property name="jdbcUrl" value="${jdbc.url}"/>
        <property name="user" value="${jdbc.username}"/>
        <property name="password" value="${jdbc.password}"/>
        
        <!-- c3p0连接池的私有属性 -->
        <property name="maxPoolSize" value="30"/>
        <property name="minPoolSize" value="10"/>
        <!-- 关闭连接不自动commit -->
        <property name="autoCommitOnClose" value="false"/>
        <!-- 获取连接超时时间 -->
        <property name="checkoutTimeout" value="10000"/>
        <!-- 当获取连接失败时重试次数 -->
        <property name="acquireRetryAttempts" value="2"/>
    </bean>
    

    <!-- 3、配置mybatis的sqlSessionFactory -->
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource" />
        <!-- 自动扫描mappers.xml文件 -->
        <property name="mapperLocations" value="classpath:mapper/*.xml"/>
        <!-- 扫描mybatis-config文件 -->
        <property name="configLocation" value="classpath:mybatis-config.xml"/>
        <!-- 扫描entity包，使用别名,或者在mybatis-config中配置,二选一 -->
        <property name="typeAliasesPackage" value="com.zhu.ssm.entity"></property>
    </bean>

    <!-- 4、DAO接口所在包名，Spring会自动查找其下的类 -->
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <property name="basePackage" value="com.zhu.ssm.dao" />
        <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"></property>
    </bean>

</beans>

spring-service.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:p="http://www.springframework.org/schema/p"  
    xmlns:aop="http://www.springframework.org/schema/aop"   
    xmlns:context="http://www.springframework.org/schema/context"  
    xmlns:jee="http://www.springframework.org/schema/jee"  
    xmlns:tx="http://www.springframework.org/schema/tx"  
    xsi:schemaLocation="    
        http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.0.xsd  
        http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd  
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd  
        http://www.springframework.org/schema/jee http://www.springframework.org/schema/jee/spring-jee-4.0.xsd  
        http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd">    
        
    <!-- 扫描service包下所有使用注解的类型 -->
    <context:component-scan base-package="com.zhu.ssm.service"/>
    
    <!-- 事务管理 -->
    <bean id="transactionManager"
        class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <property name="dataSource" ref="dataSource" />
    </bean>
    
    <!-- 开启声明式事物 -->
    <tx:annotation-driven transaction-manager="transactionManager"/>
    
</beans>

spring-web.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:p="http://www.springframework.org/schema/p"
    xmlns:aop="http://www.springframework.org/schema/aop" xmlns:context="http://www.springframework.org/schema/context"
    xmlns:jee="http://www.springframework.org/schema/jee" xmlns:tx="http://www.springframework.org/schema/tx"
    xmlns:mvc="http://www.springframework.org/schema/mvc"
    xsi:schemaLocation="    
        http://www.springframework.org/schema/mvc
        http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd
        http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.0.xsd  
        http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd  
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd  
        http://www.springframework.org/schema/jee http://www.springframework.org/schema/jee/spring-jee-4.0.xsd  
        http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd">
    <!-- 配置springmvc -->
    <!-- 1、开启springMvc注解模式 -->
    <mvc:annotation-driven />
    <context:component-scan base-package="com.zhu.ssm.controller"/>

</beans>

注意:spring-web.xml中还可以配置视图解析器、文件上传器、静态资源的处理等，因为本案例未涉及这些内容，所以没有配置。
5、对web.xml进行配置
需要在web.xml中进行如下配置，让web容器能够加载到spring的配置文件:

<!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>
  <servlet>
        <servlet-name>spring-dispatcher</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:spring/spring-.xml</param-value>
        </init-param>
    </servlet>
    <servlet-mapping>
        <servlet-name>spring-dispatcher</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>
</web-app>

至此，就完成了环境的搭建了，接下来就可以进行代码的编写了！

二、分层编写代码:

1、entity层:
User.java

public class User {
    private Integer userId;
    private String userName;
    private Integer age;
    private Card card;//一个人一张身份证,1对1
    private List<MobilePhone> mobilePhone;//土豪,多个手机,1对多
}

Card.java

public class Card {
    private Integer cardId;
    private String cardNum;//身份证号
    private String address;//地址
}

MobilePhone.java

public class MobilePhone {
    private Integer mobilePhoneId;
    private String brand;//品牌
    private double price;//价格
    private User user;//主人
}

注意:以上实体类均省略了set和get方法。
2、数据库设计:
借助数据库客户端工具navicat进行数据库以及表的创建。

tb_mobile_phone中以user_id作为外键关联tu_user，tb_user中以card_id作为外键关联tb_card。

3、dao层:
UserDao.java

/**
     * 带条件分页查询：
     *     可输入的条件：名字(模糊)，cardId，age,
     * @param userCondition 把条件封装成一个user对象
     * @param rowIndex 表示从第几行开始取数据
     * @param pageSize 表示要返回多少行数据
     * @return 返回user列表
     */
    List<User> queryUserList(@Param("userCondition") User userCondition, @Param("rowIndex") int rowIndex,
            @Param("pageSize") int pageSize);

UserDao.xml

<?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.zhu.ssm.dao.UserDao">

    <resultMap type="User" id="userMap">
          <id property="userId" column="user_id"/>
          <result property="userName" column="user_name"/>
          <result property="age" column="age"/>
          <association property="card" column="card_id" javaType="Card">
            <id property="cardId" column="card_id"/>
            <result property="cardNum" column="card_num"/>
            <result property="address" column="address"/>
          </association>
          <collection property="mobilePhone" column="user_id" ofType="MobilePhone">
            <id column="mobile_phone_id" property="mobilePhoneId" />
            <result column="brand" property="brand" />
            <result column="price" property="price" />
          </collection>
    </resultMap>
    
    <!-- 带条件分页查询 -->
    <select id="queryUserList" resultMap="userMap">
        SELECT
        u.user_name,u.age,u.card_id,c.card_num,c.address,m.brand,m.price
        FROM
        tb_user u,tb_card c,tb_mobile_phone m
        <where>
            <if
                test="userCondition.card != null
                     and 
                    userCondition.card.cardId != null">
                and u.card_id =
                #{userCondition.card.cardId}
            </if>

            <if test="userCondition.userName != null">
                and u.user_name like '%${userCondition.userName}%'
            </if>
            <if test="userCondition.age != null">
                and u.age = #{userCondition.age}
            </if>
            AND
            u.card_id = c.card_id
            AND
            u.user_id = m.user_id
        </where>
        LIMIT #{rowIndex},#{pageSize}
    </select>
    
</mapper> 

dao层的带条件分页查询用到了mybatis的动态sql，对动态sql不熟悉的请参考:mybatis笔记整理
养成良好习惯，写完dao应该做个Junit测试:

BaseTest.java

/**
 * 初始化spring各项配置的
 * @author zhu
 *
 */
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration({"classpath:spring/spring-dao.xml","classpath:spring/spring-service.xml"})
public class BaseTest {
    

}

注意:BaseTest.java是用来加载spring配置文件的。
UserDaoTest.java

public class UserDaoTest extends BaseTest {
    @Autowired
    private UserDao userDao;
    
    
    @Test
    public void testQueryUserList() {
        User userCondition = new User();
        /*Card c = new Card();
        c.setCardId(2);
        userCondition.setCard(c);*/
        //userCondition.setAge(22);
        userCondition.setUserName("菲");
        List<User> ul = userDao.queryUserList(userCondition, 1, 99);
        for(User user : ul) {
            System.out.println(user.getUserName());
            /*List<MobilePhone> list = new ArrayList<>();
            list = user.getMobilePhone();
            for(MobilePhone mp : list) {
                System.out.println(mp.getBrand());
            }*/
        }
    }
    
}

userCondition设置了userName一个"菲"字，就是模糊查询名字中带"菲"字的用户。
先看数据库表中的数据:

数据表中名字带"菲"字的用户只有"刘亦菲"，正常运行的话应该输出"刘亦菲"。
再看运行结果:

在控制台输出了"刘亦菲"，符合预期，测试通过。

4、service层:
UserService.java

public interface UserService {
    
    
    /**
     * 带条件分页查询：
     *     可输入的条件：名字(模糊)，cardId，age,
     * @param userCondition 把条件封装成一个user对象
     * @param rowIndex 表示从第几行开始取数据
     * @param pageSize 表示要返回多少行数据
     * @return 返回user列表
     /
    List<User> queryUserList(@Param("userCondition") User userCondition, @Param("rowIndex") int rowIndex,
            @Param("pageSize") int pageSize);
    
    
}

UserServiceImpl.java

@Service
public class UserServiceImpl implements UserService {
    
    @Autowired
    private UserDao userDao;

    
    @Override
    public List<User> queryUserList(User userCondition, int rowIndex, int pageSize) {
        // TODO Auto-generated method stub
        return userDao.queryUserList(userCondition, rowIndex, pageSize);
    }

    
}

由于service层只是简单的调用了dao层，这里不再做Junit测试。

5、controller层:
UserController.java

@Controller
@RequestMapping("/user")
public class UserController {
    @Autowired
    private UserService userService;

    @RequestMapping(value = "/listusers", method = RequestMethod.GET)
    @ResponseBody
    public Map<String, Object> listUsers() {
        Map<String, Object> modelMap = new HashMap<>();
        User userCondition = new User();
        List<User> userList = userService.queryUserList(userCondition, 1, 99);
        modelMap.put("userList", userList);
        return modelMap;
    }

}

至此，已完成所有代码。接下来，在浏览器输入:
localhost:8080/ssm/user/listusers
在页面就可以看到访问结果了:

注意:
图片中有几个值为null，是因为查询UserDao.xml中写查询语句时并没有查这几个字段，自己加上就行了。

总结:

常见问题:
1、做测试的时候一定要在BaseTest中加载spring 配置文件，其他test在继承BaseTest。
2、一定不要忘记web.xml中的配置，且路径一定要写对，否则web容器加载不到spring 配置文件，访问controller时会报404错误。
3、由于tb_user中的card_id作为外键关联了tb_card，所以为user设置card时，cardId一定得是tb_card中存在的，否则会报错，user_id也是tb_mobile_phone的外键，同样的道理。

以上内容属于个人笔记整理，如果错误，欢迎大家批评指正!