使用MyBatis集成阿里巴巴druid连接池（不使用spring）

• • 在工作中发现mybatis默认的连接池POOLED，运行时间长了会报莫名其妙的连接失败错误。因此采用阿里巴巴的Druid数据源（码云链接 ，中文文档链接）。 mybatis更多数据源参考博客链接 。

    1 环境

    eclipse mars2 + maven3.3.9 + mysql5.7

    2 开发过程

    项目码云地址链接

    文件目录结构如下： 

    2.0 建立数据表

    在本地mysql数据库中建立名为test的database，并建立user表：

    
    CREATE DATABASE test default charset=utf8;
    
    CREATE TABLE `user` (
      `name` varchar(64) DEFAULT NULL,
      `age` int(11) DEFAULT NULL
    ) ENGINE=InnoDB DEFAULT CHARSET=utf8;
    
    insert  into `user`(`name`,`age`) values ('叶莜落',27),('张三丰',128);
    

    2.1 建立一个maven工程，POM文件如下：

    <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/xsd/maven-4.0.0.xsd">
      <modelVersion>4.0.0</modelVersion>
      <groupId>com.yeyouluo.mybatis.druid</groupId>
      <artifactId>mybatis-druid</artifactId>
      <version>0.0.1-SNAPSHOT</version>
    
      <properties>
          <myabtis.version>3.4.1</myabtis.version>
      </properties>
    
      <dependencies>
           <dependency>
                <groupId>org.mybatis</groupId>
                <artifactId>mybatis</artifactId>
                <version>${myabtis.version}</version>
            </dependency>
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <version>5.1.30</version>
            </dependency>
            <dependency>
                <groupId>com.alibaba</groupId>
                <artifactId>druid</artifactId>
                <version>1.0.14</version>
            </dependency>
      </dependencies>
    </project>
    

    2.2 配置文件

    ①db.properties

    driver=com.mysql.jdbc.Driver
    url=jdbc:mysql://localhost:3306/test
    username=root
    password=root
    

    ②mybatis-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>
        <!-- 引用db.properties配置文件 -->
        <properties resource="db.properties" />
    
        <typeAliases>
            <typeAlias type="com.yeyouluo.mybatis.druid.utils.DruidDataSourceFactory"
                alias="DRUID" />
        </typeAliases>
    
        <!-- development : 开发模式 work : 工作模式 -->
        <environments default="work">
            <environment id="work">
                <transactionManager type="JDBC" />
                <!-- 配置数据库连接信息 -->
                <dataSource type="DRUID">
                    <!-- value属性值引用db.properties配置文件中配置的值 -->
                    <property name="driver" value="${driver}" />
                    <property name="url" value="${url}" />
                    <property name="username" value="${username}" />
                    <property name="password" value="${password}" />
                </dataSource>
            </environment>
        </environments>
    
        <!-- mybatis的mapper文件，每个xml配置文件对应一个接口 -->
        <mappers>
            <mapper resource="mapper/userMapper.xml" />
        </mappers>
    </configuration>
    

    ③在resources目录下建立userMapper.xml

    <?xml version="1.0" encoding="UTF-8" ?>
    <!DOCTYPE mapper PUBLIC "-//ibatis.apache.org//DTD Mapper 3.0//EN"
     "http://ibatis.apache.org/dtd/ibatis-3-mapper.dtd">
    <mapper namespace="com.yeyouluo.mybatis.druid.dao.userDao">
        <select id="findAllUsers" resultType="com.yeyouluo.mybatis.druid.pojo.User">
            select * from user
        </select>
    </mapper>
    

    2.3 实体类 User

    package com.yeyouluo.mybatis.druid.pojo;
    
    public class User {
    
        private String name;
        private int age;
    
        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;
        }
    
        @Override
        public String toString() {
            return "User [name=" + name + ", age=" + age + "]";
        }
    
    }
    

    2.4 工具类

    ①DruidDataSourceFactory.java

    package com.yeyouluo.mybatis.druid.utils;
    
    import java.sql.SQLException;
    import java.util.Properties;
    import javax.sql.DataSource;
    import org.apache.ibatis.datasource.DataSourceFactory;
    import com.alibaba.druid.pool.DruidDataSource;
    
    public class DruidDataSourceFactory implements DataSourceFactory {
        private Properties props;
    
        @Override
        public DataSource getDataSource() {
            DruidDataSource dds = new DruidDataSource();
            dds.setDriverClassName(this.props.getProperty("driver"));
            dds.setUrl(this.props.getProperty("url"));
            dds.setUsername(this.props.getProperty("username"));
            dds.setPassword(this.props.getProperty("password"));
            // 其他配置可以根据MyBatis主配置文件进行配置
            try {
                dds.init();
            } catch (SQLException e) {
                e.printStackTrace();
            }
            return dds;
        }
    
        @Override
        public void setProperties(Properties props) {
            this.props = props;
        }
    }
    

    ②MyBatisUtil.java

    package com.yeyouluo.mybatis.druid.utils;
    
    import java.io.InputStream;
    
    import org.apache.ibatis.io.Resources;
    import org.apache.ibatis.session.SqlSession;
    import org.apache.ibatis.session.SqlSessionFactory;
    import org.apache.ibatis.session.SqlSessionFactoryBuilder;
    
    public class MyBatisUtil {
        private static final String configFile = "mybatis-config.xml";
    
        /**
         * 创建连接
         */
        public static SqlSession getSession() {
            SqlSession session = null;
            try {
                InputStream is = Resources.getResourceAsStream(configFile);
                SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(is);
                session = factory.openSession();
            } catch (Exception e) {
                e.printStackTrace();
            }
            return session;
        }
    
        public static void closeSession(SqlSession session) {
            session.close();
        }
    
        public static void main(String[] args) {
            SqlSession session = MyBatisUtil.getSession();
            System.out.println(session);
            session.close();
        }
    }
    

    2.5 DAO

    ①接口IUserDao.java

    package com.yeyouluo.mybatis.druid.dao;
    
    import java.util.List;
    
    import com.yeyouluo.mybatis.druid.pojo.User;
    
    public interface IUserDao {
        public List<User> findAllUsers();
    }
    

    ②实现类UserDao.java

    package com.yeyouluo.mybatis.druid.dao.impl;
    
    import java.util.List;
    
    import org.apache.ibatis.session.SqlSession;
    
    import com.yeyouluo.mybatis.druid.dao.IUserDao;
    import com.yeyouluo.mybatis.druid.pojo.User;
    import com.yeyouluo.mybatis.druid.utils.MyBatisUtil;
    
    public class UserDao implements IUserDao {
    
        private static final String namespace = "com.yeyouluo.mybatis.druid.dao.userDao.";
    
        @Override
        public List<User> findAllUsers() {
            List<User> users = null;
            SqlSession session = MyBatisUtil.getSession();
            try {
                users = session.selectList(namespace + "findAllUsers", User.class);
                //注意：此处有陷阱，如果做了更新、插入或删除操作，必须使用：
                //session.commit();
            } catch (Exception e) {
                e.printStackTrace();
            }finally{
                MyBatisUtil.closeSession(session);
            }
            return users;
        }
    
    }
    

    2.6 测试类UserDaoTest.java

    package com.yeyouluo.mybatis.druid.dao.test;
    
    import java.util.List;
    
    import com.yeyouluo.mybatis.druid.dao.IUserDao;
    import com.yeyouluo.mybatis.druid.dao.impl.UserDao;
    import com.yeyouluo.mybatis.druid.pojo.User;
    
    public class UserDaoTest {
    
        public static void main(String[] args) {
            // TODO Auto-generated method stub
            IUserDao userDao = new UserDao();
            List<User> users= userDao.findAllUsers();
    
            for(User user : users){
                System.out.println(user.toString());
            }
        }
    
    }
    

    3 结果

    

    4 参考

    Jar程序使用MyBatis集成阿里巴巴druid连接池