mybatis入门案例

最新推荐文章于 2025-05-16 19:47:17 发布

路人甲M

最新推荐文章于 2025-05-16 19:47:17 发布

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分类专栏： mybatis 文章标签：后端

本文链接：https://blog.youkuaiyun.com/m0_48483101/article/details/107966300

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1.概述
MyBatis 是一款优秀的持久层框架，它支持定制化 SQL、存储过程以及高级映射。MyBatis 避免了几乎所有的 JDBC
代码和手动设置参数以及获取结果集。MyBatis 可以使用简单的 XML 或注解来配置和映射原生信息，将接口和 Java
的 POJOs(Plain Ordinary Java Object,普通的 Java对象)映射成数据库中的记录。
2.获取mybatis
maven仓库
3.入门案例
思路：搭建环境—>导入mybatis—>编写代码–>测试
1.创建普通的maven工程
在这里插入图片描述

2.在pom.xml文件下引入依赖

<dependencies>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.5</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.38</version>
        </dependency>
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.12</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.11</version>
            <scope>test</scope>
        </dependency>
    </dependencies>

在这里插入图片描述
3.configuration核心配置文件
创建xml文件

<?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>
<!--别名-->
<typeAliases>
<package name="com.entiy"></package>
</typeAliases>
    <environments default="mysql">
        <environment id="mysql">
            <transactionManager type="JDBC"></transactionManager>
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://localhost:3306/schooldb?useSSL=false"/>
                <property name="username" value="root"/>
                <property name="password" value="123456"/>
            </dataSource>
        </environment>
    </environments>
     <!--每一个mapper.xml都需要在核心配置文件中注册  -->
    <mappers>
        <package name="com.dao"></package>
    </mappers>
</configuration>

3.引入实体类
Student:

package com.entiy;

public class Student {
    private int StudentID;
    private String StudentName;
    private String Gender;
    private int Age;

    public Student() {
    }

    public Student(int studentID, String studentName, String gender, int age) {
        StudentID = studentID;
        StudentName = studentName;
        Gender = gender;
        Age = age;
    }

    public int getStudentID() {
        return StudentID;
    }

    public void setStudentID(int studentID) {
        StudentID = studentID;
    }

    public String getStudentName() {
        return StudentName;
    }

    public void setStudentName(String studentName) {
        StudentName = studentName;
    }

    public String getGender() {
        return Gender;
    }

    public void setGender(String gender) {
        Gender = gender;
    }

    public int getAge() {
        return Age;
    }

    public void setAge(int age) {
        Age = age;
    }

    @Override
    public String toString() {
        return "Student{" +
                "StudentID=" + StudentID +
                ", StudentName='" + StudentName + '\'' +
                ", Gender='" + Gender + '\'' +
                ", Age=" + Age +
                '}';
    }
}

Cesi:

package com.entiy;

import java.io.Serializable;

public class Cesi implements Serializable {
    private int id;
    private String productname;
    private int parent_id;

    public Cesi() {
    }

    public Cesi(int id, String productname, int parent_id) {
        this.id = id;
        this.productname = productname;
        this.parent_id = parent_id;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getProductname() {
        return productname;
    }

    public void setProductname(String productname) {
        this.productname = productname;
    }

    public int getParent_id() {
        return parent_id;
    }

    public void setParent_id(int parent_id) {
        this.parent_id = parent_id;
    }

    @Override
    public String toString() {
        return "Cesi{" +
                "productname='" + productname + '\'' +
                ", parent_id=" + parent_id +
                '}';
    }
}

4.编写持久层StudentDao接口

package com.dao;

import com.entiy.Cesi;
import com.entiy.Student;

import java.util.List;

public interface IstudentDao {
    List<Student> selectStudent();
    Student selectStudentById(int id);
    int insertStudent(Student student);
    int updateStudent(Student student);
    int deleteStudentByid(int id);
    List<Student> selectStudentLike(String likeName);
    int insertStudentForId(Cesi cesi);
}

5.编写持久层配置文件StudentDao.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">
<!--namespace：绑定对应的dao/mapper接口-->
<mapper namespace="com.dao.IstudentDao" >
    <!--id对应dao层方法名    resultType:返回值,增删改不写   parameterType参数类型-->
    <select id="selectStudent" resultType="com.entiy.Student" parameterType="com.entiy.Student">
        select * from studentinfo
    </select>
    <insert id="insertStudent" parameterType="Student">
        insert into studentinfo(StudentID,StudentName,Gender,Age) values(#{StudentID},
        #{StudentName},#{Gender},#{Age})
    </insert>
    <select id="selectStudentById" resultType="Student" parameterType="int">
        select * from studentinfo where StudentID=#{id}
    </select>
    <update id="updateStudent" parameterType="Student" >
        update studentinfo set StudentName=#{StudentName},
        Gender=#{Gender},Age=#{Age} where StudentID=#{StudentID}
    </update>
    <delete id="deleteStudentByid" parameterType="int">
        delete from studentinfo where studentid=#{id}
    </delete>
    <select id="selectStudentLike" parameterType="String" resultType="Student">
        select  * from studentinfo where studentName like #{likeName}
    </select>
    <!--useGeneratedKeys设置为 true 时，表示如果插入的表id以自增列为主键，则允许 JDBC 支持自动生成主键，并可将自动生成的主键id返回。
useGeneratedKeys参数只针对 insert 语句生效，默认为 false；-->
    <insert id="insertStudentForId" parameterType="Cesi" useGeneratedKeys="true" keyColumn="id" keyProperty="id">
        insert into product(productname,parent_id) values(#{productname},#{parent_id})
    </insert>
</mapper>

在这里插入图片描述
6.创建测试类

package com;

import com.dao.IstudentDao;
import com.entiy.Cesi;
import com.entiy.Student;
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 java.io.InputStream;
import java.util.List;

public class myBatisTest {
    public static void main(String[] args) {
        try{
        //1.读取配置文件
        InputStream inputStream= Resources.getResourceAsStream("myBatisconfig.xml");
        SqlSessionFactoryBuilder builder=new SqlSessionFactoryBuilder();
        SqlSessionFactory sqlSessionFactory=builder.build(inputStream);
        SqlSession sqlSession=sqlSessionFactory.openSession();
        IstudentDao mapper = sqlSession.getMapper(IstudentDao.class);
        //查询
    /* List<Student> students = mapper.selectStudent();
        for (Student s:students) {
            System.out.println(s);
        }*/
      //新增
          /*  Student student=new Student();
            student.setStudentID(000);
            student.setStudentName("sss");
            student.setAge(20);
            student.setGender("男");
            int i = mapper.insertStudent(student);
            System.out.println(i);
            sqlSession.commit();*/
          //根据id获取对象
           /* Student student = mapper.selectStudentById(44);
            System.out.println(student);*/
           //修改
           /* Student student=new Student();
            student.setAge(200);
            student.setStudentName("df");
            student.setStudentID(44);
            student.setGender("女");
            int i = mapper.updateStudent(student);
            System.out.println(i);
            sqlSession.commit();*/
           //删除
            /*int i = mapper.deleteStudentByid(0);
            System.out.println(i);
            sqlSession.commit();*/
            //模糊查询
        /*    List<Student> students = mapper.selectStudentLike("%马%");
            System.out.println(students);*/
        //获取自增id
            Cesi cesi=new Cesi();
            cesi.setProductname("aaa");
            cesi.setParent_id(9);
            int i = mapper.insertStudentForId(cesi);
            System.out.println(cesi.getId());
            sqlSession.commit();
        }catch (Exception e){

            e.printStackTrace();
        }
}}

7.配置mybatis的日志，在resouces目录下创建log4j.properties

# Set root category priority to INFO and its only appender to CONSOLE.
#log4j.rootCategory=INFO, CONSOLE            debug   info   warn error fatal
log4j.rootCategory=debug, CONSOLE, LOGFILE

# Set the enterprise logger category to FATAL and its only appender to CONSOLE.
log4j.logger.org.apache.axis.enterprise=FATAL, CONSOLE

# CONSOLE is set to be a ConsoleAppender using a PatternLayout.
log4j.appender.CONSOLE=org.apache.log4j.ConsoleAppender
log4j.appender.CONSOLE.layout=org.apache.log4j.PatternLayout
log4j.appender.CONSOLE.layout.ConversionPattern=%d{ISO8601} %-6r [%15.15t] %-5p %30.30c %x - %m\n

# LOGFILE is set to be a File appender using a PatternLayout.
log4j.appender.LOGFILE=org.apache.log4j.FileAppender
log4j.appender.LOGFILE.File=mybatis.log
log4j.appender.LOGFILE.Append=true
log4j.appender.LOGFILE.layout=org.apache.log4j.PatternLayout
log4j.appender.LOGFILE.layout.ConversionPattern=%d{ISO8601} %-6r [%15.15t] %-5p %30.30c %x - %m\n