Mybatis入门crud

╰+攻爆jí腚メ 2022-05-17 01:15 282阅读 0赞

学习参考自[NAYNEHC博客园][NAYNEHC]

该框架使用方法有很多，当前使用 \[javaBean\]Mapper.xml  简单映射接口实现增删改查的方法：

配置mybatis有---<configuration>

-------><properties>属性文件配置，如数据库，日记记录

-------><environments>配置环境（可多个，如各种数据库厂商）

-----------------------------><environment>其中一个

--------------------------------------------------><transactionManager>事务管理

--------------------------------------------------><dataSource>配置数据源

-------><mappers>映射注册配置（可多个）

----------------------><mapper>一个映射类位置

配置映射类 \[javaBean\]Mapper.xml，对数据库sql语句映射 如：

<insert id="insertStudent">  
        insert into student(sno,sname,score) values(\#\{sno\},\#\{sname\},\#\{score\})  
    </insert>

具体实现例子如下：

1、结构目录，需要导入mybatis、mysql的jar包

![70][]

2、mybatis.cfg.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>
    	
    	<properties resource="mysql.properties"/>
    	
    	<environments default="develpment">
    		<environment id="develpment">
    			<transactionManager type="JDBC"/>
    			
    			<dataSource type="POOLED">
    				<property name="driver" value="${driver}"/>
    				<property name="url" value="${url}"/>
    				<property name="username" value="${user}"/>
    				<property name="password" value="${password}"/>
    			</dataSource>
    		</environment>
    	
    	</environments>
    	
    	<mappers>
    		<mapper resource="com/crud/mapper/StudentMapper.xml"/>
    		
    	</mappers>
    	
    </configuration>

3、mysql.properties

![70 1][]

4、Student实体类

package com.crud.model;
    
    public class Student {
    
    	private int sno;
    	private String sname;
    	private double score;
    	
    	@Override
    	public String toString() {
    		return "Student [sno=" + sno + ", sname=" + sname + ", score=" + score + "]";
    	}
    	public Student() {
    		super();
    	}
    	public Student(int sno, String sname, double score) {
    		super();
    		this.sno = sno;
    		this.sname = sname;
    		this.score = score;
    	}
    	public int getSno() {
    		return sno;
    	}
    	public void setSno(int sno) {
    		this.sno = sno;
    	}
    	public String getSname() {
    		return sname;
    	}
    	public void setSname(String sname) {
    		this.sname = sname;
    	}
    	public double getScore() {
    		return score;
    	}
    	public void setScore(double score) {
    		this.score = score;
    	}
    }

5、mapper包下的crud方法接口类，实现类、对象的sql映射文件

package com.crud.mapper;
    
    import java.util.List;
    
    import com.crud.model.Student;
    
    public interface InterStudentMapper {
    
    	public int insertStudent(Student student);
    	
    	public int deleteStudent(int sno);
    	
    	public int updateStudent(Student student);
    	
    	public Student selectStudent(int sno);
    	
    	public List<Student> selectAllStudent();
    }

package com.crud.mapper;
    
    import java.util.List;
    
    import org.apache.ibatis.session.SqlSession;
    
    import com.crud.model.Student;
    import com.crud.tool.DBtool;
    
    public class StudentMapperImpl implements InterStudentMapper {
    
    	@Override
    	public int insertStudent(Student student) {
    		SqlSession sqlSession=DBtool.getSqlSession();
    		InterStudentMapper mapper=sqlSession.getMapper(InterStudentMapper.class);
    		try{	//线程不安全类型，放在方法体中。
    			mapper.insertStudent(student);
    			sqlSession.commit();
    			System.out.println("had inserted:"+student);
    		}catch(Exception e){
    			e.printStackTrace();
    			sqlSession.rollback();
    			return 1;
    		}finally{
    			sqlSession.close();
    		}
    		return 0;
    	}
    
    	@Override
    	public int deleteStudent(int sno) {
    		SqlSession sqlSession=DBtool.getSqlSession();
    		InterStudentMapper mapper=sqlSession.getMapper(InterStudentMapper.class);
    		try{
    			mapper.deleteStudent(sno);
    			sqlSession.commit();
    			System.out.println("had deleted:"+sno);
    		}catch(Exception e){
    			e.printStackTrace();
    			sqlSession.rollback();
    			return 1;
    		}finally{
    			sqlSession.close();
    		}
    		return 0;
    	}
    
    	@Override
    	public int updateStudent(Student student) {
    		SqlSession sqlSession=DBtool.getSqlSession();
    		InterStudentMapper mapper=sqlSession.getMapper(InterStudentMapper.class);
    		try{
    			Student before=mapper.selectStudent(student.getSno());
    			mapper.updateStudent(student);
    			sqlSession.commit();
    			Student after=mapper.selectStudent(student.getSno());
    			sqlSession.commit();
    			System.out.println(before+" had changed:"+after);
    		}catch(Exception e){
    			e.printStackTrace();
    			sqlSession.rollback();
    			return 1;
    		}finally{
    			sqlSession.close();
    		}
    		return 0;
    	}
    
    	@Override
    	public Student selectStudent(int sno) {
    		Student stu=null;
    		SqlSession sqlSession=DBtool.getSqlSession();
    		InterStudentMapper mapper=sqlSession.getMapper(InterStudentMapper.class);
    		try{
    			stu=mapper.selectStudent(sno);
    			sqlSession.commit();
    		}catch(Exception e){
    			e.printStackTrace();
    			sqlSession.rollback();
    			return null;
    		}finally{
    			sqlSession.close();
    		}
    		return stu;
    	}
    
    	@Override
    	public List<Student> selectAllStudent() {
    		List<Student> list=null;
    		SqlSession sqlSession=DBtool.getSqlSession();
    		InterStudentMapper mapper=sqlSession.getMapper(InterStudentMapper.class);
    		try{
    			list=mapper.selectAllStudent();
    			sqlSession.commit();
    		}catch(Exception e){
    			e.printStackTrace();
    			sqlSession.rollback();
    			return null;
    		}finally{
    			sqlSession.close();
    		}
    		return list;
    		
    	}
    
    }

<?xml version="1.0" encoding="UTF-8"?>
     <!DOCTYPE mapper PUBLIC "-//mybatis.org/DTD Mapper 3.0" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
    
    <mapper namespace="com.crud.mapper.InterStudentMapper">
    	
    	
    	<resultMap id="StudentMap" type="com.crud.model.Student">
    		<id property="sno" column="sno" javaType="java.lang.Integer"/>
    		<result property="sname" column="sname" javaType="java.lang.String"/>
    		<result property="score" column="score" javaType="java.lang.Double"/>
    	</resultMap>
    	
    	
    	<insert id="insertStudent">
    		                
    		insert into student(sno,sname,score) values(#{sno},#{sname},#{score})
    	</insert>
    			
    	<update id="updateStudent" parameterType="com.crud.model.Student">
    		update student set sname=#{sname},score=#{score} where sno=#{sno}
    	</update>
    			
    	<delete id="deleteStudent" parameterType="int">
    		delete from student where sno=#{sno}
    	</delete>
    			
    	<select id="selectStudent" resultType="com.crud.model.Student">
    		select * from student where sno=#{sno}
    	</select>
    	
    	<select id="selectAllStudent" resultMap="StudentMap">
    		select * from student
    	</select>
    
    </mapper>

6、数据库操作工具类

package com.crud.tool;
    
    import java.io.IOException;
    import java.io.Reader;
    
    import org.apache.ibatis.io.Resources;
    import org.apache.ibatis.session.SqlSession;
    import org.apache.ibatis.session.SqlSessionFactory;
    import org.apache.ibatis.session.SqlSessionFactoryBuilder;
    
    public class DBtool {
    
    	public static SqlSessionFactory sqlSessionFactory;
    	
    	static{
    		try {
    			Reader reader=Resources.getResourceAsReader("mybatis.cif.xml");
    			sqlSessionFactory=new SqlSessionFactoryBuilder().build(reader);
    		} catch (IOException e) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		}
    	}
    	
    	public static SqlSession getSqlSession(){
    		return sqlSessionFactory.openSession();
    	}
    }

7、增删改查服务测试

package com.crud.service;
    
    import java.util.List;
    
    import com.crud.mapper.InterStudentMapper;
    import com.crud.mapper.StudentMapperImpl;
    import com.crud.model.Student;
    
    public class StudentService{
    	public static void main(String[] args) {
    		
    		InterStudentMapper stuMapper=new StudentMapperImpl();
    		
    		stuMapper.insertStudent(new Student(1002,"gan",100));
    		
    		stuMapper.deleteStudent(1100);
    		
    		stuMapper.updateStudent(new Student(1000,"master",88));
    		
    		Student stu=stuMapper.selectStudent(1001);
    		System.out.println(stu);
    		
    		List<Student> list=stuMapper.selectAllStudent();
    		System.out.println(list);
    	}
    	 
    }

8、结果

![70 2][]

前

![70 3][]

后

![70 4][]

[NAYNEHC]: https://www.cnblogs.com/hellokitty1/p/5216025.html
[70]: /images/20220517/4f532b22a359482bbbb5802fa3081545.png
[70 1]: /images/20220517/9541b97e7a26425f9817b7428ed9ba74.png
[70 2]: /images/20220517/3e26847a2d894005a37b95de193ffbb6.png
[70 3]: /images/20220517/728f58ac423741bcb5c817bbd8d5185a.png
[70 4]: /images/20220517/ab3a70afbcf84702b8cfed98b8c2baf1.png