在上已个Java Spring MVC项目基础上加MyBatis

代码目录：

/Users/baidu/Documents/Data/Work/Code/Self/HelloSpringMVC

1. 首先在resource目录加上jdbc.properties：

driverClasss=com.mysql.jdbc.Driver
jdbcUrl=jdbc:mysql://10.117.x.x:8306/springdemo?useUnicode=true&characterEncoding=utf-8&zeroDateTimeBehavior=convertToNull
username=x
password=x

#定义初始连接数
initialSize=0
#定义最大连接数
maxActive=20
#定义最大空闲
maxIdle=20
#定义最小空闲
minIdle=1
#定义最长等待时间
maxWait=60000

2. 在pom.xml里面添加如下依赖：

<properties>
    <spring.version>4.2.6.RELEASE</spring.version>
    <mybatis.version>3.2.8</mybatis.version>
    <mysql-driver.version>5.1.29</mysql-driver.version>
  </properties>

<!-- 添加mybatis依赖 -->  
    <dependency>  
      <groupId>org.mybatis</groupId>  
      <artifactId>mybatis</artifactId>  
      <version>${mybatis.version}</version>  
    </dependency>  
  
    <!-- 添加mybatis/spring整合包依赖 -->  
    <dependency>  
      <groupId>org.mybatis</groupId>  
      <artifactId>mybatis-spring</artifactId>  
      <version>1.2.2</version>  
    </dependency>  
  
    <!-- 添加mysql驱动依赖 -->  
    <dependency>  
      <groupId>mysql</groupId>  
      <artifactId>mysql-connector-java</artifactId>  
      <version>${mysql-driver.version}</version>  
    </dependency>  
    <!-- 添加数据库连接池依赖 -->  
    <dependency>  
      <groupId>commons-dbcp</groupId>  
      <artifactId>commons-dbcp</artifactId>  
      <version>1.2.2</version>  
    </dependency>  

3. 把之前的applicationContext.xml配置 refactor成 spring-mybatis.xml，用refactor菜单的时候，web.xml里面如下也会改：

 <context-param>
    <param-name>contextConfigLocation</param-name>
    <param-value>/WEB-INF/spring-mybatis.xml</param-value>
  </context-param>

4. 最终写成的spring-mybatis.xml如下：

<?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/cache"
       xmlns:contex="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/cache http://www.springframework.org/schema/cache/spring-cache.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">

    <contex:component-scan base-package="com.webapp.hello"/>

    <bean id="propertyConfigurer" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
        <property name="location" value="classpath:jdbc.properties"/>
    </bean>

    <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
        <property name="driverClassName" value="${driverClasss}"/>
        <property name="url" value="${jdbcUrl}"/>
        <property name="username" value="${username}"/>
        <property name="password" value="${password}"/>
        <property name="initialSize" value="${initialSize}"/>
        <property name="maxActive" value="${maxActive}"/>
        <property name="maxIdle" value="${maxIdle}"/>
        <property name="minIdle" value="${minIdle}"/>
        <property name="maxWait" value="${maxWait}"/>
    </bean>

    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" value="dataSource"/>
        <property name="mapperLocations" value="classpath:mapping/*.xml"/>
    </bean>

    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <property name="basePackage" value="com.webapp.hello.dao"/>
        <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"/>
    </bean>

</beans>

5. 几个代码文件如下：

HelloController

package com.webapp.hello;

import com.webapp.hello.dao.UserDao;
import com.webapp.hello.model.User;
import org.springframework.stereotype.Controller;
import org.springframework.ui.ModelMap;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

import javax.annotation.Resource;
import java.util.LinkedList;
import java.util.List;

/**
 * Created by baidu on 16/10/7.
 */
@Controller
public class HelloController {

    @Resource
    UserDao userDao;

    @RequestMapping(value="/", method= RequestMethod.GET)
    public String index(ModelMap modelMap) {
        /*List userList = new LinkedList();
        userList.add("张三");
        userList.add("李四");
        modelMap.addAttribute("userList", userList);*/

        List<User> userList = userDao.selectAllUser();
        modelMap.addAttribute("userList", userList);
        return "hello";
    }
}

model/User

package com.webapp.hello.model;

/**
 * Created by baidu on 16/10/8.
 */
public class User {
    private Long id;
    private String userName;

    public String getUserName() {
        return userName;
    }

}

dao/UserDao

package com.webapp.hello.dao;

import com.webapp.hello.model.User;
import org.springframework.stereotype.Repository;

import java.util.List;

/**
 * Created by baidu on 16/10/8.
 */
@Repository
public interface UserDao {
    List<User> selectAllUser();
}

mapping/UserMapper.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.webapp.hello.dao.UserDao">
    <resultMap id="UserMap" type="com.webapp.hello.model.User">
        <id column="id" property="id" jdbcType="BIGINT"/>
        <result column="user_name" property="userName" jdbcType="VARCHAR"/>
    </resultMap>

    <select id="selectAllUser" resultMap="UserMap">
        SELECT id, user_name FROM t_user
    </select>

</mapper>

Jsp文件，对user加上属性：

${user.userName}

运行之后，首先报的一个错，是针对sqlSessionFactory初始话，不能convert string to DataSource。对比排查后，在spring-mybatis.xml里面改了下面第二行的value变成 ref：

<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource"/>
        <property name="mapperLocations" value="classpath:mapping/*.xml"/>
    </bean>

然后再运行，报错找不到class，是commons/pool等，应该就是commons-pool的依赖，所以在pom.xml加上对commons-pool的依赖：

<!-- https://mvnrepository.com/artifact/commons-pool/commons-pool -->
    <dependency>
      <groupId>commons-pool</groupId>
      <artifactId>commons-pool</artifactId>
      <version>1.6</version>
    </dependency>

然后再运行，就可以成功显示了：