MyBatis-简单运行

MyBatis的简单运行

全局配置文件

配置文件与映射文件存在于根目录

<?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">
				<property name="driver" value="com.mysql.jdbc.Driver" />
				<property name="url" value="jdbc:mysql://localhost:3306/test" />
				<property name="username" value="root" />
				<property name="password" value="123456" />
			</dataSource>
		</environment>
	</environments>
	
	<!-- 将写好的sql映射文件（StudentMapper.xml）一定要注册到全局配置文件（mybatis-config.xml）中 -->
	<mappers>
		<mapper resource="StudentMapper.xml" />
	</mappers>
</configuration>

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">
<mapper namespace="Dao.StudentDao">
<!-- 
namespace:名称空间;这里指定为接口的全类名
id：唯一标识,使用接口的方法名称
resultType：返回值类型
#{id}：从传递过来的参数中取出id值
 -->
 
 	<!-- public Student getStudentId(Integer id); -->
	<select id="getStudentId" resultType="student.Student">
		select * from user where id = #{id}
	</select>
	
	<!-- public void updateStudent(Integer id,String Name,String sex); 
		 public void updateStudent(@Param("id")Integer id,@Param("name")String Name,@Param("sex")String sex);
	-->
	<update id="updateStudent">
		<!-- 当有多个参数时无法使用属性名来进行绑定,可以使用param1.....paramN 来进行绑定
		update user set name=#{param2},sex=#{param3} where id=#{param1}	-->
		<!-- 如要使用属性名绑定使用@param("")来进行绑定 -->
		update user set name=#{name},sex=#{sex} where id=#{id}
	</update>
	
	<!-- public void addStudent(Student student); -->
	<insert id="addStudent">
		insert into user(name,sex) values(#{name},#{sex})
	</insert>
	
	<!-- public void deleteStudent(Integer id); -->
	<delete id="deleteStudent">
		delete from user where id=#{id}
	</delete>
</mapper>

实体类

package student;

public class Student {
	private Integer Id;
	private String Name;
	private String Sex;
	
	public Integer getId() {
		return Id;
	}
	public void setId(Integer id) {
		Id = id;
	}
	public String getName() {
		return Name;
	}
	public void setName(String name) {
		Name = name;
	}
	public String getSex() {
		return Sex;
	}
	public void setSex(String sex) {
		Sex = sex;
	}
	@Override
	public String toString() {
		return "Student [Id=" + Id + ", Name=" + Name + ", Sex=" + Sex + "]";
	}
	public Student(String name, String sex) {
		super();
		Name = name;
		Sex = sex;
	}
	public Student() {
		super();
		// TODO Auto-generated constructor stub
	}
	
	
}

接口

package Dao;

import org.apache.ibatis.annotations.Param;

import student.Student;

public interface StudentDao {

	public Student getStudentId(Integer id);
	
	public void addStudent(Student student);
	
	public void updateStudent(@Param("id")Integer id,@Param("name")String Name,@Param("sex")String sex);
	
	public void deleteStudent(Integer id);
}

测试类

package student.mybatis;

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.junit.jupiter.api.Test;

import Dao.StudentDao;
import student.Student;

class MyBatis_Test {
	
	public SqlSessionFactory getSqlSessionFactory() throws IOException {
		String resource = "mybatis-config.xml";
		InputStream inputStream = Resources.getResourceAsStream(resource);
		return new SqlSessionFactoryBuilder().build(inputStream);
	}
	/**
	 * 1、根据xml配置文件（全局配置文件）创建一个SqlSessionFactory对象 有数据源一些运行环境信息
	 * 2、sql映射文件；配置了每一个sql，以及sql的封装规则等。 
	 * 3、将sql映射文件注册在全局配置文件中
	 * 4、写代码：
	 * 		1）、根据全局配置文件得到SqlSessionFactory；
	 * 		2）、使用sqlSession工厂，获取到sqlSession对象使用他来执行增删改查
	 * 			一个sqlSession就是代表和数据库的一次会话，用完关闭
	 * 		3）、使用sql的唯一标志来告诉MyBatis执行哪个sql。sql都是保存在sql映射文件中的。
	 * 
	 * @throws IOException
	 */
	//基础方式
	@Test
	public void test() throws Exception {
		// 2、获取sqlSession实例，能直接执行已经映射的sql语句
				// sql的唯一标识：statement Unique identifier matching the statement to use.
				// 执行sql要用的参数：parameter A parameter object to pass to the statement.
				SqlSessionFactory sqlSessionFactory = getSqlSessionFactory();

				SqlSession openSession = sqlSessionFactory.openSession();
				try {
						//命名空间+id,这里没使用接口绑定,StudentMapper 随便起的命名空间，getStudentById id名称
					Student student = openSession.selectOne("StudentMapper.getStudentById", 1);
					System.out.println(student);
				} finally {
					openSession.close();
				}
	}
	//推荐使用这种方法
	@Test
	public void test1() throws IOException {
		//1.获取SqlSessionFactory
		SqlSessionFactory sqlSessionFactory = getSqlSessionFactory();
		
		//2.获取sqlSession
		SqlSession openSession = sqlSessionFactory.openSession();
		//3.获取接口实现类对象
		//为接口自动创建一个代理对象，代理对象执行增删改查
		try {
		StudentDao studentDao = openSession.getMapper(StudentDao.class);
		//4.调用方法
		Student student =studentDao.getStudentId(1);
		System.out.println(student);
		}finally {
			openSession.close();
		}
	}
	
	@Test
	public void test3() throws IOException {
		SqlSessionFactory sqlSessionFactory = getSqlSessionFactory();
		SqlSession openSession = sqlSessionFactory.openSession();
		StudentDao studentDao = openSession.getMapper(StudentDao.class);
		//Student student = new Student("李四","男");
		try {
			//添加方法
			//studentDao.addStudent(student);
			//删除方法
			//studentDao.deleteStudent(6);
			//修改方法
			studentDao.updateStudent(7,"李四", "男");
			//手动提交 可以设置sqlSessionFactory.openSession(true)
			openSession.commit();
		}finally {
			openSession.close();
		}
	}

}