学习Mybatis中数据库操作的初次使用

一、下载mybatis.jar包，导入项目。

二、创建实体类：org.ruangong.entity。

package org.ruangong.entity;

import org.apache.ibatis.reflection.SystemMetaObject;

public class Person {
	
private int id;
public int getId() {
	return id;
}
public void setId(int id) {
	this.id = id;
}
public Person() {

}
public Person(int id, String name, int age) {
	super();
	this.id = id;
	this.name = name;
	this.age = 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;
}
private String name;
private int age;
@Override
public String toString() {
	return "Person [id=" + id + ", name=" + name + ", age=" + age + "]";
}


}

　　三、创建personMapper.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="org.ruangong.mapper.personMapper">

	 <select id="queryPersonById" resultType="org.ruangong.entity.Person" parameterType="int">
	 	select * from person where id = #{id}
	 </select>
	 
	 <insert id="add" parameterType="org.ruangong.entity.Person">
	 	insert into person(id,name,age) value(#{id},#{name},#{age})
	 </insert>
	  
	  <delete id="delete" parameterType="int">
	  	delete from person where id = #{id}
	  </delete>
	  
	  <select id="queryall" resultType="org.ruangong.entity.Person">
	  	select * from person
	  </select>
	  
	  <update id="updatePerson" parameterType="org.ruangong.entity.Person">
	  	update person set name=#{name},age=#{age} where id=#{id}
	  </update>
	  
</mapper>

　　四、创建配置文件conf.xml，配置数据库连接

<?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>
	 <environments default="development">
		 <environment id="development">
		 <transactionManager type="JDBC"/>
		 <dataSource type="POOLED">//连接池，提升性能
			 <property name="driver" value="${driver}"/>
			 <property name="url" value="${url}"/>
			 <property name="username" value="${username}"/>
			 <property name="password" value="${password}"/>
		 </dataSource>
		 </environment>
	 </environments>
	 <mappers>
		 <mapper resource="org/ruangong/mapper/personMapper.xml"/>
	 </mappers>
</configuration>

　　五、实现数据库操作：

package org.ruangong.test;


import java.io.IOException;
import java.io.Reader;
import java.util.List;

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.ruangong.entity.Person;
import org.ruangong.mapper.personMapper;

public class TestMybatis {
	public static void queryOnePerson() throws IOException{
		//加载配置文件
		Reader reader = Resources.getResourceAsReader("conf.xml");
		//SqlsessionFactory -- conection
		 SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(reader);
		 SqlSession session = sessionFactory.openSession();
		 String statement="org.ruangong.mapper.personMapper.queryPersonById";
		 Person person = session.selectOne(statement,1);
		 System.out.println(person.getAge()+","+person.getId()+","+person.getName());
		 session.close();
	}
	public static void addOnePerson() throws IOException{
		//加载配置文件
		Reader reader = Resources.getResourceAsReader("conf.xml");
		//SqlsessionFactory -- conection
		 SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(reader);
		 SqlSession session = sessionFactory.openSession();
		 String statement="org.ruangong.mapper.personMapper.add";
		 Person person=new Person(2,"疯狗伟",80);
		 int count = session.insert(statement,person);
		 System.out.println("增加行数："+count);
		 session.commit();
		 session.close();
	}
	public static void deleteOnePerson() throws IOException{
		//加载配置文件
		Reader reader = Resources.getResourceAsReader("conf.xml");
		//SqlsessionFactory -- conection
		 SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(reader);
		 SqlSession session = sessionFactory.openSession();
		 String statement="org.ruangong.mapper.personMapper.delete";
		 int count = session.delete(statement,2);
		 System.out.println("删除行数："+count);
		 session.commit();
		 session.close();
	}
	public static void queryAllPerson() throws IOException{
		//加载配置文件
		Reader reader = Resources.getResourceAsReader("conf.xml");
		//SqlsessionFactory -- conection
		 SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(reader);
		 SqlSession session = sessionFactory.openSession();
		 String statement="org.ruangong.mapper.personMapper.queryall";
		 List<Person> list = session.selectList(statement);
         System.out.println(list);
		 session.close();
	}
	public static void updatePerson() throws IOException{
		//加载配置文件
		Reader reader = Resources.getResourceAsReader("conf.xml");
		//SqlsessionFactory -- conection
		 SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(reader);
		 SqlSession session = sessionFactory.openSession();
		 String statement="org.ruangong.entity.personMapper.updatePerson";
		 Person person = new Person();
		 person.setId(1);
		 person.setName("疯狗伟");
		 person.setAge(30);
		 session.update(statement, person);
         session.commit();
		 session.close();
	}

	
public static void main(String[] args) throws IOException {
	//queryOnePerson();
	//addOnePerson();
	//deleteOnePerson();
//	queryAllPerson();
//	updatePerson();
	queryPerson2();
//	addPerson2();
}
}

　　收获：在传统连接数据库上，用到了连接池提高了数据库操作性能。