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!