优化配置
1.提取properties配置文件
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提取jdbc.properties配置文件 Mybatis-config.xml依然采用${driverName}的方式来引用
通过properties建立两者之间的联系
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直接上代码：
1.建个项目：
2.建包，建配置文件
3.con.qf.entity包中创建实体类User：
package com.qf.entity;
public class User {
private Integer id;
private String name;
private String password;
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
@Override
public String toString() {
return "User [id=" + id + ", name=" + name + ", password=" + password + "]";
}
}
4.con.qf.dao包中创建接口
package com.qf.dao;
import java.util.List;
import com.qf.entity.User;
public interface IUserDao {
public User getUserById(Integer id);
public void add(User user);
public void delete(Integer id);
public void update(User user);
public List<User> getUserList();
}
5.com.qf.mapper包创建接口的映射文件
<?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">
<!-- namespace指的就是接口的全类名 -->
<mapper namespace="com.qf.dao.IUserDao">
<!--
id:方法名称
resultType:返回类型
-->
<select id="getUserById" resultType="com.qf.entity.User">
select * from t_user where id = #{id}
</select>
<!-- parameterType:方法的参数类型 -->
<insert id="add" parameterType="com.qf.entity.User">
insert into t_user (name,password) values(#{name},#{password})
</insert>
<update id="update">
update t_user set name = #{name},password = #{password} where id = #{id}
</update>
<delete id="delete" parameterType="java.lang.Integer">
delete from t_user where id = #{id}
</delete>
<!--
方法返回集合的时候resultType要配置集合中的类型
-->
<select id="getUserList" resultType="com.qf.entity.User">
select * from t_user
</select>
</mapper>
6.com.qf.util工具类
package com.qf.utils;
import java.io.IOException;
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;
import org.xml.sax.InputSource;
public class MyBatisUtil {
private static SqlSessionFactory sqlSessionFactory;
public static SqlSessionFactory getSqlSessionFactory() {
if (sqlSessionFactory == null) {
initSqlSessionFactory(); // 为空再去参加
}
return sqlSessionFactory;
}
private static void initSqlSessionFactory() {
InputStream ips = null;
try {
// 1.指定配置文件
ips = Resources.getResourceAsStream("mybatis-config.xml");
// 2.赋值操作
synchronized (MyBatisUtil.class) {
if (sqlSessionFactory == null) {
sqlSessionFactory = new SqlSessionFactoryBuilder().build(ips);
}
}
} catch (IOException e) {
e.printStackTrace();
} finally {
if (ips != null) {
try {
ips.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
}
7.配置mybatis-config.xml配置文件
<?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> <!-- 指定使用哪个environment --> <environments default="development"> <environment id="development"> <!-- 事务管理器 --> <transactionManager type="JDBC" /> <!-- 连接池，POOLED是MyBatis提供的链接池 --> <dataSource type="POOLED"> <!-- 链接数据库的参数 --> <property name="driver" value="com.mysql.jdbc.Driver" /> <property name="url" value="jdbc:mysql://localhost:3306/1707_hibernate" /> <property name="username" value="root" /> <property name="password" value="root" /> </dataSource> </environment> </environments> <!-- Mapper文件 --> <mappers> <mapper resource="com/qf/mapper/IUserDao.xml" /> </mappers> </configuration>
8.配置jdbc.properties配置文件
jdbc.url =jdbc:mysql://localhost:3306/1707_hibernate jdbc.name=root jdbc.password=root jdbc.driver=com.mysql.jdbc.Driver
9.到mybatis-config.xml里面去配置读取jdbc.properties文件
<?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> <!-- 加载属性文件 resource:加载本地资源文件 url:远程的资源 如果调用远程的接口，返回的是key-value形式信息，通过key去取值 --> <properties resource="jdbc.properties"></properties> <environments default="development"> <environment id="development"> <transactionManager type="JDBC" /> <dataSource type="POOLED"> <property name="driver" value="${jdbc.driver}" /> <property name="url" value="${jdbc.url}" /> <property name="username" value="${jdbc.name}" /> <property name="password" value="${jdbc.password}" /> </dataSource> </environment> </environments> <!-- Mapper文件 --> <mappers> <mapper resource="com/qf/mapper/IUserDao.xml" /> </mappers> </configuration>
测试类：
package com.qf.dao;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.log4j.Logger;
import org.junit.Test;
import com.qf.entity.User;
import com.qf.utils.MyBatisUtil;
public class UserDaoTest {
private Logger logger = Logger.getLogger(UserDaoTest.class);
@Test
public void testGetUserById() {
SqlSession sqlSession = MyBatisUtil.getSqlSessionFactory().openSession();
IUserDao userDao = sqlSession.getMapper(IUserDao.class);
User user = userDao.getUserById(9);
sqlSession.close();
}
}
总结：
1.属性文件的读取
1)加载属性文件
a)<properties resource="jdbc.properties">
2)通过$(属性文件中的key)符号获取值
