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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
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>${myabtis.version}</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.30</version>
</dependency>
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid</artifactId>
<version>1.0.14</version>
</dependency>
</dependencies>
</project>2.2 配置文件
①db.properties
driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/test
username=root
password=root②mybatis-config.xml
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
<!-- 引用db.properties配置文件 -->
<properties resource="db.properties" /> <typeAliases>
<typeAlias type="com.yeyouluo.mybatis.druid.utils.DruidDataSourceFactory"
alias="DRUID" />
</typeAliases> <!-- development : 开发模式 work : 工作模式 -->
<environments default="work">
<environment id="work">
<transactionManager type="JDBC" />
<!-- 配置数据库连接信息 -->
<dataSource type="DRUID">
<!-- value属性值引用db.properties配置文件中配置的值 -->
<property name="driver" value="${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
-
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