ssm(spring、springmvc、mybatis)框架整合

第一次接触这3大框架，打算一个一个慢慢学，参照网上资料搭建了一个ssm项目，作为新手吃亏在jar包的导入上，比如jdbc DataSource配置的时候由于导入的jar包不兼容或者缺包导致项目无法正常运行，commons-dbcp-1.4.jar和commons-pool-1.6.jar导进来之后就解决了，但是这个问题就搞了一个晚上。

1.项目结构

 控制器依赖服务层的接口不依赖具体的实现，服务层依赖dao接口层不依赖具体数据访问层。数据持久层使用mybatis框架来完成CRUD操作。config文件下存放所以实体的映射XML文件，一个dao接口对于一个xml实现，sql语句都写在XML文件中。

之前写的项目基本都是这样的架构：分层、依赖抽象。spring框架在这里的作用就是一个容器，它管理着项目里的具体实现：服务层的具体实现，数据访问层的具体实现，当controller想要某个实现spring容器就会注入进具体的service。spring还有一个作用就是AOP编程，这块暂时还没学到先不管它。

springmvc框架在项目里作用就是处理用户请求，用户输入一个url（http://localhost:8080/ssm/employee/list）springmvc会根据url去找对应的controller方法，并返回一个view(jsp页面)给用户。

2.配置

2.1 web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"   version="3.1">
  <!--spirng 容器配置 -->
  <!--ContextLoaderListener监听器会在网站启动时初始化Spring容器 -->
  <context-param>
    <param-name>contextConfigLocation</param-name>
    <param-value>classpath:spring-mybatis.xml</param-value>
  </context-param>
  <listener>
    <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
  </listener>
 
  <servlet>
  <!--springmvc配置  加载前端控制器 -->
  <servlet-name>springmvc</servlet-name>
  <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
  <!-- 
       加载配置文件
       默认加载规范：
       * 文件命名：servlet-name-servlet.xml====springmvc-servlet.xml
       * 路径规范：必须在WEB-INF目录下面
       修改加载路径：
   -->
   <init-param>
   <param-name>contextConfigLocation</param-name>
   <param-value>classpath:springmvc.xml</param-value>   
   </init-param>
  </servlet>
  <servlet-mapping>
  <servlet-name>springmvc</servlet-name>
  <url-pattern>/</url-pattern>
  </servlet-mapping>
</web-app>

2.2 springmvc.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: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-4.0.xsd
        http://www.springframework.org/schema/mvc 
        http://www.springframework.org/schema/mvc/spring-mvc-4.0.xsd
        http://www.springframework.org/schema/context 
        http://www.springframework.org/schema/context/spring-context-4.0.xsd">
    <!-- springmvc只负责页面转发 -->
    <!-- 只扫描控制器 -->
    <context:component-scan base-package="com.ssmdemo.controller"></context:component-scan>


    <!-- 配置一个注解驱动，如果配置此标签，那么就可以不用配置处理器映射器和处理器适配器 -->
    <mvc:annotation-driven />
    <!-- 处理静态资源 -->
    <mvc:default-servlet-handler />
    <!-- 配置视图解析器 -->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/jsp/"></property>
        <property name="suffix" value=".jsp"></property>
    </bean>
</beans>

2.3 spring-mybatis.xml

<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:jdbc="http://www.springframework.org/schema/jdbc"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:mybatis="http://mybatis.org/schema/mybatis-spring"
    xsi:schemaLocation="http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd
     http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
     http://www.springframework.org/schema/jdbc http://www.springframework.org/schema/jdbc/spring-jdbc.xsd
     http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd
     http://mybatis.org/schema/mybatis-spring http://mybatis.org/schema/mybatis-spring.xsd">

    <!-- spring希望管理所有的逻辑组件。。等 -->
    <context:component-scan    base-package="com.ssmdemo">
        <context:exclude-filter type="annotation" expression="org.springframework.web.servlet.mvc.Controller" />
    </context:component-scan>
    <!-- 加载配置文件 -->
    <context:property-placeholder location="classpath:db.properties" />
    <!-- 数据库连接池 -->
    <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
        <property name="driverClassName" value="${jdbc.driver}" />
        <property name="url" value="${jdbc.url}" />
        <property name="username" value="${jdbc.username}" />
        <property name="password" value="${jdbc.password}" />
        <property name="maxActive" value="10" />
        <property name="maxIdle" value="5" />
    </bean>

    <!-- transaction manager, use DataSourceTransactionManager" for JDBC local tx -->
    <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <property name="dataSource" ref="dataSource" />
    </bean>
    <!-- 开启基于注解的事务 -->
    <tx:annotation-driven transaction-manager="transactionManager" />
    <!-- mapper配置 -->
    <!-- 让spring管理sqlsessionfactory 使用mybatis和spring整合包中的 -->
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <!-- 数据库连接池 -->
        <property name="dataSource" ref="dataSource" />
        <!-- 自动扫描mybatis配置文件,这里就配置控制台打印sql -->
          <property name="configLocation" value="classpath:mybatis-config.xml"></property>
        <!-- 制定mapper文件的位置 -->
         <property name="mapperLocations" value="classpath:mybatis/mapper/*.xml" />
    </bean>
    <!-- 配置Mapper扫描器 -->
    <!-- scan for mappers and let them be autowired -->
    <mybatis:scan base-package="com.ssmdemo.dao" />

</beans>

数据库连接字符串反正db.properties文件内

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost/mybatis
jdbc.username=root
jdbc.password=123456

下面是 mybatis-config.xml的配置，用来在控制台打印mybatis执行的sql语句

<?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>
    <settings>
        <!-- 打印查询语句 -->
        <setting name="logImpl" value="STDOUT_LOGGING" />
    </settings>
</configuration>

config下的EmployeeMapper.xml配置

<?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.ssmdemo.dao.EmployeeMapper">
    <select id="getEmployeeList" resultType="com.ssmdemo.model.Employee">
        select * from employee
    </select>
</mapper>

 3.项目代码

3.1 EmployeeController.java

@Controller
@RequestMapping("/employee")
public class EmployeeController {
    @Autowired
    private EmployeeService employeeService;
    @RequestMapping("/list")
    public ModelAndView list() {
        ModelAndView mv = new ModelAndView();
        
        List<Employee> emps = employeeService.getEmployees();
        mv.setViewName("employee/list");
        mv.addObject("employees", emps);
        return mv;
    }
}

 3.2 EmployeeService.java

public interface EmployeeService {
    List<Employee> getEmployees();
}

 3.3 EmployeeServiceImpl.java

@Service
public class EmployeeServiceImpl implements EmployeeService {

    @Autowired
    EmployeeMapper employeeMapper;

    @Override
    public List<Employee> getEmployees() {
        return employeeMapper.getEmployeeList();
    }

}

3.4 EmployeeMapper.java

public interface EmployeeMapper {
    List<Employee> getEmployeeList();
}

3.5 Employee.java

public class Employee {
    @Override
    public String toString() {
        return "Employee [employeeId=" + employeeId + ", name=" + name + ", age=" + age + ", birthday=" + birthday
                + "]";
    }
    private int employeeId;
    private String name;
    private int age;
    private Date birthday;
    public int getEmployeeId() {
        return employeeId;
    }
    public void setEmployeeId(int employeeId) {
        this.employeeId = employeeId;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    public Date getBirthday() {
        return birthday;
    }
    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }
}

3.6 list.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>ssm整合demo</title>
</head>
<body>
<c:forEach items="${employees}" var="item">
   姓名: <c:out value="${item.name}" /><br/>
</c:forEach>
</body>
</html>