MyBatis入门程序（基于XML配置）

Posted 2021-01-12 HEAVEN_1

创建一个简单的MyBatis入门程序，实现对学生信息的增删改查功能（基于XML配置）

一、新建一个Java工程，导入MyBatis核心jar包、日志相关的jar包以及连接Oracle数据库所需驱动包，目录结构如下

二、创建MyBatis核心配置文件mybatis-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>
	<!-- 引入资源文件 -->
	<properties resource="db.properties"></properties>
	<environments default="development">
		<environment id="development">
			<!-- 配置事务管理方式 -->
			<transactionManager type="JDBC" />
			<!-- 配置数据源 -->
			<dataSource type="POOLED">
				<property name="driver" value="${driver}" />
				<property name="url" value="${url}" />
				<property name="username" value="${username}" />
				<property name="password" value="${password}" />
			</dataSource>
		</environment>
	</environments>
	<!-- 指定映射文件 -->
	<mappers>
		<mapper resource="com/heaven/dao/StudentMapper.xml"/>
	</mappers>
</configuration>

 三、创建POJO类Student.java

package com.heaven.bean;

import java.util.Date;

public class Student {
	private Integer studId;
	private String name;
	private String email;
	private Date dob;
	
	public Student() {
	}
	
	public Student(Integer studId, String name, String email, Date dob) {
		this.studId = studId;
		this.name = name;
		this.email = email;
		this.dob = dob;
	}

	public Integer getStudId() {
		return studId;
	}
	public void setStudId(Integer studId) {
		this.studId = studId;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public String getEmail() {
		return email;
	}
	public void setEmail(String email) {
		this.email = email;
	}
	public Date getDob() {
		return dob;
	}
	public void setDob(Date dob) {
		this.dob = dob;
	}
	@Override
	public String toString() {
		return "Student [studId=" + studId + ", name=" + name + ", email=" + email + ", dob=" + dob + "]";
	}
	
}

 四、创建StudentMapper.xml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="com.heaven.dao.StudentMapper">
	<!-- 保存学生信息 -->
	<insert id="saveStudent" parameterType="com.heaven.bean.Student">
		insert into students(stud_id,name,email,dob) values(#{studId},#{name},#{email},#{dob})
	</insert>
	<!-- 根据Id查询学生信息 -->
	<select id="selectById" parameterType="Integer" resultType="com.heaven.bean.Student">
		select stud_id studId,name,email,dob from students where stud_id = #{id}
	</select>
	<!-- 查询所有学生信息 -->
	<select id="findAll" resultType="com.heaven.bean.Student">
		select stud_id studId,name,email,dob from students
	</select>
	<!-- 更新学生信息 -->
	<update id="updateStudent" parameterType="com.heaven.bean.Student">
		update students set email = #{email} where stud_id = #{studId}
	</update>
	<!-- 根据Id删除学生信息 -->
	<delete id="deleteById" parameterType="Integer">
		delete from students where stud_id = #{id}
	</delete>
</mapper> 

 五、创建映射接口StudentMapper.java

package com.heaven.dao;

import java.util.List;

import com.heaven.bean.Student;

public interface StudentMapper {
    /**
     * 保存学生信息
     * @param stu 入参 ：Student对象
     */
    void saveStudent(Student stu);
    /**
     * 根据id查询学生信息
     * @param id 入参：id
     * @return 返回值：Student对象
     */
    Student selectById(Integer id);
    /**
     * 查询所有学生信息
     */
    List<Student> findAll();
    /**
     * 删除学生信息
     * @param id 入参：id
     */
    void deleteById(Integer id);
    /**
     * 更新学生信息：入参：Student对象
     * @param stu
     */
    void updateStudent(Student stu);
}

六、编写JUnit测试类Test.java

package com.heaven.test;

import java.io.IOException;
import java.util.Date;
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.junit.Before;
import org.junit.Test;

import com.heaven.bean.Student;
import com.heaven.dao.StudentMapper;

public class TestMapper {
    private SqlSessionFactory factory;
    private SqlSession sqlSession;
    private StudentMapper mapper;
    /**
     * 执行测试方法之前执行，用于创建SqlSessionFactory并获取SqlSession对象
     */
    @Before
    public void init() {
        try {
            //创建SqlSessionFactory，加载mybatis核心配置文件
            factory = new SqlSessionFactoryBuilder().build(Resources.getResourceAsStream("mybatis-config.xml"));
            //获取SqlSession接口对象
            sqlSession = factory.openSession();
            //使用动态代理方式创建mapper接口的代理对象
            mapper = sqlSession.getMapper(StudentMapper.class);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    @Test
    public void saveStudent() {
        Student stu = new Student(1001,"TOM","123456",new Date());
        mapper.saveStudent(stu);
        sqlSession.commit();
        sqlSession.close();
    }

    @Test
    public void selectById(){
        Student student = mapper.selectById(1001);
        System.out.println(student);
    }
    @Test
    public void findAll(){
        List<Student> list = mapper.findAll();
        System.out.println(list.toString());
    }
    
    @Test
    public void updateStudent(){
        Student stu = new Student(1001, "Tom", "123@", new Date());
        mapper.updateStudent(stu);
        sqlSession.commit();
    }
    
    @Test
    public void deleteById(){
        mapper.deleteById(1001);
        sqlSession.commit();
    }
}

七、其他相关文件

数据库连接配置db.properties

driver=oracle.jdbc.driver.OracleDriver
url=jdbc:oracle:thin:@127.0.0.1:1521:XE
username=heaven
password=heaven

log4j配置文件log4j.properties

#设置日志输出级别，输出方式
log4j.rootLogger=DEBUG, stdout 
log4j.appender.stdout=org.apache.log4j.ConsoleAppender 
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout 
log4j.appender.stdout.layout.ConversionPattern=%d [%-5p] %c - %m%n
#show sql
log4j.logger.java.sql.ResultSet=INFO  
log4j.logger.org.apache=INFO  
log4j.logger.java.sql.Connection=DEBUG  
log4j.logger.java.sql.Statement=DEBUG  
log4j.logger.java.sql.PreparedStatement=DEBUG