Mybatis使用注解完成CRUD操作

Mybatis使用注解完成CRUD操作

使用注解比xml文件方便简单许多

这里完成最简单的CRUD操作

如果读者想使用的话，只需要修改数据库名就可以直接使用。

详细的解释大家可以看上一篇博文。

首先看实体类

package hym.bean;

public class student {
    private int id;
    private String name;
    private int age;
    private float score;
    private int tid;   //这是teacherID
    public student() {

    }
    public student(int id, String name, int age, float score, int tid) {
        this.id = id;
        this.name = name;
        this.age = age;
        this.score = score;
        this.tid = tid;
    }

    public int getId() {
        return id;
    }

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

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public float getScore() {
        return score;
    }

    public void setScore(float score) {
        this.score = score;
    }

    public int getTid() {
        return tid;
    }

    public void setTid(int tid) {
        this.tid = tid;
    }

    @Override
    public String toString() {
        return "student{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", age=" + age +
                ", score=" + score +
                ", tid=" + tid +
                '}';
    }
}

再来看看mapper

就是在mapper接口中使用注解来完成CRUD

package hym.mapper;

import hym.bean.student;
import org.apache.ibatis.annotations.Delete;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Select;
import org.apache.ibatis.annotations.Update;

import java.util.List;

public interface StudentMapper {
    @Select("select * from student")
    List<student> SeletALL();
    @Delete("delete from student where id = #{id}")
    int DeleteStudent(int id);
    @Insert("insert into student values(#{id},#{name},#{age},#{score},#{tid})")
    int InsertStudent(student student);
    @Update("update student set score = #{score} where id = #{id}")
    int UpdateStudent(student student);

}

最后看看主要的实现方法

package hym;


import hym.bean.student;
import hym.mapper.StudentMapper;
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.IOException;
import java.io.InputStream;
import java.util.List;

public class main {
    public static void main(String[] args) {
        InputStream inputStream = null;
        SqlSessionFactory sqlSessionFactory = null;
        try {
            inputStream = Resources.getResourceAsStream("mybatis-cfg.xml");
             sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        } catch (IOException e) {
            e.printStackTrace();
        }
        SqlSession sqlSession = sqlSessionFactory.openSession();
        //使用xml文件方法
        /*List<Teacher> objects = sqlSession.selectList("com.hym.SelectTeacherAll");
        for(Teacher s : objects){
            System.out.println(s.toString());
        }*/
        StudentMapper studentMapper = sqlSession.getMapper(StudentMapper.class);
        //查询全部
        /*List<student> students = studentMapper.SeletALL();
        for (student s : students){
            System.out.println(s.toString());
        }*/
        //增加学生
        /*student student = new student(8,"小勇",23,67,1);
        int i = studentMapper.InsertStudent(student);
        System.out.println(i);*/
        //删除学生
        /*int i = studentMapper.DeleteStudent(8);
        System.out.println(i);*/
        //修改学生信息，此处修改学生分数
        student student = new student();
        student.setId(1);
        student.setScore(100);
        int i = studentMapper.UpdateStudent(student);
        System.out.println(i);
        sqlSession.commit();
        sqlSession.close();
    }
}

配置文件

<?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>
    <!--配置数据库 别名等-->
    <!--配置别名-->
    <!--<typeAliases>
        &lt;!&ndash;<typeAlias type="com.hym.bean.Student" alias="stu"/>&ndash;&gt;
        <package name="hym.bean"/>
    </typeAliases>-->
    <!--environments 中可放置多个数据库连接方式， default后接的值 表示选择的是哪一个数据库  -->
    <environments default ="mysql">
        <!-- 声明当前是用的数据库环境 -->
        <environment id = "mysql">
            <!-- 是用原生JDBC事务 -->
            <transactionManager type="JDBC"></transactionManager>
            <!-- 使用数据库连接词 -->
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://localhost:3306/edu"/>
                <property name="username" value="root"/>
                <property name="password" value="root"/>
            </dataSource>
        </environment>
    </environments>
    <mappers>
       <package name="hym.mapper"/>
    </mappers>
</configuration>