MyBatis入门配置及简单应用

痛定思痛。 2022-06-11 02:16 164阅读 0赞

**MyBatis:**支持普通 SQL查询，[存储过程][Link 1]和高级映射的优秀[持久层][Link 2]框架。MyBatis 消除了几乎所有的[JDBC][]代码和参数的手工设置以及[结果集][Link 3]的检索。MyBatis 使用简单的 XML或注解用于配置和原始映射，将接口和 Java 的POJOs（Plain Ordinary Java Objects，普通的 Java对象）映射成数据库中的记录。

在这里简单的创建一个java web项目MyBatis:

![Center][]

在这里，StudentMapper.java相当于dao层，而StudentMapper.xml相当于dao的impl。

实体类**Student.java:**

package cn.hbue.entity;
    
    public class Student {
    
     private Integer id;
     private String name;
     private String sex;
     private String birth;
     private String department;
     private String address;
    
     public Student(){
    	 super();
     }
    
    public Integer getId() {
    	return id;
    }
    
    public void setId(Integer id) {
    	this.id = id;
    }
    
    public String getName() {
    	return name;
    }
    
    public void setName(String name) {
    	this.name = name;
    }
    
    public String getSex() {
    	return sex;
    }
    
    public void setSex(String sex) {
    	this.sex = sex;
    }
    
    public String getBirth() {
    	return birth;
    }
    
    public void setBirth(String birth) {
    	this.birth = birth;
    }
    
    public String getDepartment() {
    	return department;
    }
    
    public void setDepartment(String department) {
    	this.department = department;
    }
    
    public String getAddress() {
    	return address;
    }
    
    public void setAddress(String address) {
    	this.address = address;
    }
    
    @Override
    public String toString() {
    	return "Student [id=" + id + ", name=" + name + ", sex=" + sex + ", birth="
    			+ birth + ", department=" + department + ", address=" + address
    			+ "]";
    }
     
    public Student(Integer id,String name,String sex,String birth,String department,String address){
    	super();
    	this.id=id;
    	this.name=name;
    	this.sex=sex;
    	this.birth=birth;
    	this.department=department;
    	this.address=address;
    	
    	
    }
     
    
     
    }

数据的简单操作StudentMapper.java:

package cn.hbue.mapper;
    
    import java.util.List;
    
    import cn.hbue.entity.Student;
    
    
    /**接口类型  相当于StuedntDao **/
    public interface StudentMapper {
    	
    	public Student getStudentById(Integer id);  //通过id查询
    	public int saveStudent(Student stu);  //插入数据
    	public void updateStudent(Student stu);  //更新数据
    	public void deleteStudentById(Integer id);  //删除数据
    	
    	
    	//批量操作
    	public List<Student> getAllStudent();  
    
    }

StudentMapper.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="cn.hbue.mapper.StudentMapper">
      
    
    
      <select id="getStudentById" resultType="cn.hbue.entity.Student">
        select * from student where id = #{id}
      </select>
      <insert id="saveStudent" parameterType="cn.hbue.entity.Student">
        insert into student values(#{id},#{name},#{sex},#{birth},#{department},#{address})
      </insert>
      <update id="updateStudent" parameterType="cn.hbue.entity.Student" >
         update student set id=#{id}, name=#{name},sex=#{sex},birth=#{birth},department=#{department},address=#{address} where id=#{id}
      </update>
      <delete id="deleteStudentById" parameterType="Integer">
        delete from student where id=#{id}
      </delete>
      
      
      <resultMap type="cn.hbue.entity.Student" id="StudentList"> 
       
        <id property="idCard" column="stu_id_card"/> 
        <result property="id" column="id"/>
        <result property="name" column="name"/>
        <result property="sex" column="sex"/>
        <result property="birth" column="birth"/>
        <result property="department" column="department"/>
        <result property="address" column="address"/>
      </resultMap> 
      <select id="getAllStudent" resultMap="StudentList">
        select * from student;
      </select>
     
    
    </mapper>

mybatis的映射文件mybatis-configure.xml，处理数据库连接资源

<?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/lanou?useUnicode=true&characterEncoding=UTF8"/>
            <property name="username" value="root"/>
            <property name="password" value="123456"/>
          </dataSource>
        </environment>
      </environments>
      
      
      <mappers>
        <mapper resource="cn/hbue/mapper/StudentMapper.xml"/>
      </mappers>
    
    </configuration>

在这里，针对数据表student做了简单的增删改查以及批量的查询操作：

package cn.hbue.test;
    
    import java.io.IOException;
    import java.io.InputStream;
    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.Test;
    
    import cn.hbue.entity.Student;
    import cn.hbue.mapper.StudentMapper;
    
    public class MybatisTest {
    
    	@Test
    	public static void main(String[] args) throws IOException{
    		String resource ="mybatis-configure.xml";
    		InputStream inputStream = Resources.getResourceAsStream(resource);
            SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
    		
    		SqlSession session = sqlSessionFactory.openSession();
    		try {
    		StudentMapper mapper = session.getMapper(StudentMapper.class);
    //		Student stu_select = mapper.getStudentById(907); //查询id=907
    //		Student stu_insert = new Student(909,"幺妹儿","女","1992","舞蹈系","鄂州市鄂城区");
    //	    mapper.saveStudent(stu_insert);  //将数据插入数据库
    //    	System.out.println("查询907："+stu_select.toString()); 
    //		Student stu = mapper.getStudentById(909); //查询刚插入的数据   id=908 
    //		System.out.println("查询908："+stu.toString()); 
    //	    System.out.println("更新之后查询908："+stu.toString());
    //		Student stu_update = new Student(909,"哈哈","女","1999","舞蹈系","鄂州市鄂城区");
    //		mapper.updateStudent(stu_update);
    //		System.out.println("更新之后查询909: "+stu_update.toString());
    //	    mapper.deleteStudentById(908);  //删除成功
    //	    System.out.println("删除成功-----");
    		
    		
    	
    		List<Student> list=mapper.getAllStudent();
    		for(Student student: list){
    			System.out.println("学生信息："+student.toString());
    		}
    		System.out.println("查询所有student信息成功-----");	
    		
    		
    		session.commit();
    		}
    	   finally {
    		  session.close();
    		}
    
    	}
    
    }

[Link 1]: https://baike.baidu.com/item/%E5%AD%98%E5%82%A8%E8%BF%87%E7%A8%8B
[Link 2]: https://baike.baidu.com/item/%E6%8C%81%E4%B9%85%E5%B1%82
[JDBC]: https://baike.baidu.com/item/JDBC
[Link 3]: https://baike.baidu.com/item/%E7%BB%93%E6%9E%9C%E9%9B%86
[Center]: /images/20220611/74bf2109c83543e79584dbf8e466a9cb.png