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：文件结构

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;@Overridepublic 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()); } } }