ssm之spring+springmvc+mybatis整合初探

1、基本目录如下

 

 2、首先是向lib中加入相应的jar包

 3、然后在web.xml中加入配置，使spring和springmvc配置文件起作用。

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
    <!-- needed for ContextLoaderListener -->
    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>classpath:spring.xml</param-value>
    </context-param>

    <!-- Bootstraps the root web application context before servlet initialization -->
    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>
    
    <!-- The front controller of this Spring Web application, responsible for handling all application requests -->
    <servlet>
        <servlet-name>springDispatcherServlet</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:springmvc.xml</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>

    <!-- Map all requests to the DispatcherServlet for handling -->
    <servlet-mapping>
        <servlet-name>springDispatcherServlet</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>

</web-app>

4、新建一个conf源文件，相关配置在里面编写，即spring配置文件spring.xml，springmvc配置文件springmvc.xml，mybatis全局配置文件mybatis-conf.xml。连接数据库所需的外部引用文件dbconfig.properties。

首先我们来看mybatis-conf.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>
    <settings>
        <setting name="mapUnderscoreToCamelCase" value="true"/>
        <setting name="jdbcTypeForNull" value="NULL"/>
        
        <!--显式的指定每个我们需要更改的配置的值，即使他是默认的。防止版本更新带来的问题  -->
        <setting name="cacheEnabled" value="true"/>
        <setting name="lazyLoadingEnabled" value="true"/>
        <setting name="aggressiveLazyLoading" value="false"/>
    </settings>
    
    <databaseIdProvider type="DB_VENDOR">
        <property name="MySQL" value="mysql"/>
        <property name="Oracle" value="oracle"/>
        <property name="SQL Server" value="sqlserver"/>
    </databaseIdProvider>
    
</configuration>

在这里主要的就是一些设置<setting>，像驼峰命名、开启二级缓存、延迟加载等等。以及标识各种数据库，像mysql、oracle等等。

然后再来看看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:context="http://www.springframework.org/schema/context"
    xmlns:mvc="http://www.springframework.org/schema/mvc"
    xsi:schemaLocation="http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.0.xsd
        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-4.0.xsd">

    <!--SpringMVC只是控制网站跳转逻辑  -->
    <!-- 只扫描控制器 -->
    <context:component-scan base-package="com.gong.mybatis" use-default-filters="false">
        <context:include-filter type="annotation" expression="org.springframework.stereotype.Controller"/>
    </context:component-scan>
    
    <!-- 视图解析器 -->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/pages/"></property>
        <property name="suffix" value=".jsp"></property>
    </bean>
    
    <mvc:annotation-driven></mvc:annotation-driven>
    <mvc:default-servlet-handler/>
</beans>

主要是四个方面：

• 让springmvc只处理标识了@Controller的IOC容器
• 视图解析器
• 配置默认的servletHandler
• 配置<mvc:annotation-driven></mvc:annotation-driven>

具体用法参考以前的学习笔记。

接着看看spring.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:mybatis-spring="http://mybatis.org/schema/mybatis-spring"
    xmlns:tx="http://www.springframework.org/schema/tx"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
        http://mybatis.org/schema/mybatis-spring http://mybatis.org/schema/mybatis-spring-1.2.xsd
        http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd">

    <!-- Spring希望管理所有的业务逻辑组件，等。。。 -->
    <context:component-scan base-package="com.gong.mybatis">
        <context:exclude-filter type="annotation"
            expression="org.springframework.stereotype.Controller" />
    </context:component-scan>

    <!-- 引入数据库的配置文件 -->
    <context:property-placeholder location="classpath:dbconfig.properties" />
    <!-- Spring用来控制业务逻辑。数据源、事务控制、aop -->
    <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <property name="jdbcUrl" value="${jdbc.url}"></property>
        <property name="driverClass" value="${jdbc.driver}"></property>
        <property name="user" value="${jdbc.username}"></property>
        <property name="password" value="${jdbc.password}"></property>
    </bean>
    <!-- spring事务管理 -->
    <bean id="dataSourceTransactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <property name="dataSource" ref="dataSource"></property>
    </bean>

    <!-- 开启基于注解的事务 -->
    <tx:annotation-driven transaction-manager="dataSourceTransactionManager"/>
    
    <!-- 
    整合mybatis 
        目的：1、spring管理所有组件。mapper的实现类。
                service==>Dao   @Autowired:自动注入mapper；
            2、spring用来管理事务，spring声明式事务
    -->
    <!--创建出SqlSessionFactory对象  -->
    <bean id="sqlSessionFactoryBean" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource"></property>
        <!-- configLocation指定全局配置文件的位置 -->
        <property name="configLocation" value="classpath:mybatis-config.xml"></property>
        <!--mapperLocations: 指定mapper文件的位置-->
        <property name="mapperLocations" value="classpath:mybatis/mapper/*.xml"></property>
    </bean>
    
    <!--配置一个可以进行批量执行的sqlSession  -->
    <bean id="sqlSession" class="org.mybatis.spring.SqlSessionTemplate">
        <constructor-arg name="sqlSessionFactory" ref="sqlSessionFactoryBean"></constructor-arg>
        <constructor-arg name="executorType" value="BATCH"></constructor-arg>
    </bean>
    
    <!-- 扫描所有的mapper接口的实现，让这些mapper能够自动注入；
    base-package：指定mapper接口的包名
     -->
    <mybatis-spring:scan base-package="com.gong.mybatis.dao"/>
    <!-- <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <property name="basePackage" value="com.gong.mybatis.dao"></property>
    </bean> -->
    
</beans>

我们一个个来看：

• 首先是配置除了@Controller其余的注解皆由spring来管理
• 引入外部的数据库的信息，并进行数据库连接配置
• 配置事务管理器
• 配置基于注解的事务，即可以使用@Transactional注解
• 配置SqlSessionFactoryBean，不用我们每次都要获取SqlSessionFactory和SqlSession实例，同时引用mybatis配置文件以及mapper.xml文件存在的位置。
• 配置一个可以进行批量执行的sqlSession。
• 配置mapper.xml对应的接口文件的位置

dbconfig.properties

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/mybatis?allowMultiQueries=true
jdbc.username=root
jdbc.password=123456

5、最后就是编写相应的文件进行测试了

具体流程：bean包里存放普通的实体类，controller包里面主要是后台和视图view之间进行交互，dao包主要是相关操作数据库的方法与mybatis.mapper中的xml相对应，service主要是存放着接口，serviceImpl主要是实现service中的方法，这些方法是可以是不同数据库方法的结合使用。首先是controller调用serviceImpl中的方法，serviceImpl中的方法调用dao里面的方法，dao里面的方法对应着mapper.xml文件中操作数据库的方法，最后controller将数据传给视图view或者view通过请求到controller。

Employee.java

package com.gong.mybatis.bean;

import java.io.Serializable;

public class Employee implements Serializable{
    
    /**
     * 
     */
    private static final long serialVersionUID = 1L;
    
    public Employee() {}
    
    public Employee(Integer id, String lastName, String gender, String email) {
        super();
        this.id = id;
        this.lastName = lastName;
        this.gender = gender;
        this.email = email;
    }
    private Integer id;
    private String lastName;
    private String gender;
    private String email;
    public Integer getId() {
        return id;
    }
    public void setId(Integer id) {
        this.id = id;
    }
    public String getLastName() {
        return lastName;
    }
    public void setLastName(String lastName) {
        this.lastName = lastName;
    }
    public String getGender() {
        return gender;
    }
    public void setGender(String gender) {
        this.gender = gender;
    }
    public String getEmail() {
        return email;
    }
    public void setEmail(String email) {
        this.email = email;
    }

    @Override
    public String toString() {
        return "Employee [id=" + id + ", lastName=" + lastName + ", gender=" + gender + ", email=" + email + "]";
    }
    
}

EmployeeController.java

package com.gong.mybatis.controller;

import java.util.List;
import java.util.Map;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

import com.gong.mybatis.bean.Employee;
import com.gong.mybatis.service.EmployeeService;

@Controller
public class EmployeeController {
    @Autowired
    private EmployeeService employeeService;
    
    @RequestMapping("/getemps")
    public String emps(Map<String,Object> map) {
        List<Employee> emps = employeeService.getEmps();
        map.put("emps", emps);
        return "list";
    }
}

EmployeeService.java

package com.gong.mybatis.service;

import java.util.List;
import com.gong.mybatis.bean.Employee;

public interface EmployeeService {

    public List<Employee> getEmps();
}

EmployeeServiceImpl.java

package com.gong.mybatis.serviceImpl;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import com.gong.mybatis.bean.Employee;
import com.gong.mybatis.dao.EmployeeMapper;
import com.gong.mybatis.service.EmployeeService;

@Service
public class EmployeeServiceImpl implements EmployeeService{
    @Autowired
    private EmployeeMapper employeeMapper;
    
    public List<Employee> getEmps(){
        return employeeMapper.getEmps();
    }
}

EmployeeMapper.java

package com.gong.mybatis.dao;

import java.util.List;

import com.gong.mybatis.bean.Employee;

public interface EmployeeMapper {
    
    public List<Employee> getEmps();

}

EmployeeMapper.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.gong.mybatis.dao.EmployeeMapper">
    <select id="getEmps" resultType="com.gong.mybatis.bean.Employee">
        select id,last_name lastName,email,gender from tbl_employee
    </select>
</mapper>

6、相关视图页面

index.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<a href="getemps">查询所有员工</a>
</body>
</html>

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 PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>员工列表</title>
</head>
<body>
    <table>
        <tr>
            <td>id</td>
            <td>lastName</td>
            <td>email</td>
            <td>gender</td>
        </tr>
        <c:forEach items="${emps}" var="emp">
            <tr>
                <td>${emp.id }</td>
                <td>${emp.lastName }</td>
                <td>${emp.email }</td>
                <td>${emp.gender }</td>
            </tr>
        </c:forEach>
    
    </table>

</body>
</html>

7、启动tomcat服务器

点击查询所有员工：

得到如图所示界面，说明spring+springmvc+mybatis整合基本完成。