Mybatis实现简单增删改查

朱雀 2023-01-13 10:44 324阅读 0赞

Mybatis的简单应用

  • 学习内容：
    • 需求
    • 环境准备
    • 代码
  • 总结：

学习内容：

需求

使用Mybatis实现简单增删改查（以下是在IDEA中实现的，其他开发工具中，代码一样）

jar 包下载：https://blog.csdn.net/zzvar/article/details/115831533

环境准备

  • 添加项目需要的jar包（也可以通过配置maven，就不需要导入 jar 包了）
    1）mysql-connection-java-5.1.26-bin.jar（jar包可以根据自己需要更换）
    　　MySQL数据库的JDBC驱动包，访问MySQL必须导入的jar包
    2）mybatis-3.4.5.jar（jar包可以根据自己需要更换）
    　　MyBatis 框架的核心jar包

  • 创建 Teacher 表
    1）建表语句如下：

    DROP TABLE IF EXISTS teacher;
    CREATE TABLE teacher (
    userID int(11) NOT NULL AUTO_INCREMENT,
    userName varchar(200) CHARACTER SET utf8 COLLATE utf8_unicode_ci NOT NULL COMMENT ‘用户名’,
    sex varchar(20) CHARACTER SET utf8 COLLATE utf8_unicode_ci NULL DEFAULT NULL COMMENT ‘性别’,
    birthYear date NOT NULL COMMENT ‘生日’,
    degree varchar(20) CHARACTER SET utf8 COLLATE utf8_unicode_ci NULL DEFAULT NULL COMMENT ‘学历’,
    title varchar(255) CHARACTER SET utf8 COLLATE utf8_unicode_ci NULL DEFAULT NULL COMMENT ‘职称’,
    grade date NULL DEFAULT NULL COMMENT ‘入职时间’,
    collegeID int(11) NOT NULL COMMENT ‘院系’,
    PRIMARY KEY (userID) USING BTREE
    ) ENGINE = InnoDB AUTO_INCREMENT = 10012 CHARACTER SET = utf8 COLLATE = utf8_unicode_ci ROW_FORMAT = Dynamic;

　2）建表后结果如下图：
3aa3d2090bb6b329fa23897922c8ec47.png

　3）项目的目录结构如下（非Maven项目）：
在这里插入图片描述

代码

  • db.properties文件

    db.driverClassName=com.mysql.jdbc.Driver
    db.url=jdbc:mysql://localhost:3306/web_test02?characterEncoding=utf-8&serverTimezone=GMT%2b8:00&useSSL=false

    （这里是我的数据库名，你要用你的）

    db.username=root

    （这里是我的数据库密码，你要用你的）

    db.password=admin

  • log4j.properties 文件

    Global logging configuration

    log4j.rootLogger=ERROR, stdout

    MyBatis logging configuration…

    log4j.logger.com.yy.homework.mapper=TRACE

    Console output…

    log4j.appender.stdout=org.apache.log4j.ConsoleAppender
    log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
    log4j.appender.stdout.layout.ConversionPattern=%5p [%t] - %m%n

  • mybatis-config 文件

    <?xml version=”1.0” encoding=”UTF-8” ?>
    <!DOCTYPE configuration

    1.     PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
    2.     "http://mybatis.org/dtd/mybatis-3-config.dtd">

  • ITeacherDAO 文件

    package com.yy.homework.dao;

    import com.yy.homework.domain.Teacher;

    import java.util.List;

    / @program: Mybatis_test03 @ClassName ITeacher @description:定义实现 CRUD 的接口 @author: YanYang * @create: 2021-04-17 22:10 /
    public interface ITeacherDAO { 

    1. // 增加
    2. void insert(Teacher t);
    3. // 删除
    4. void delete(int id);
    5. // 更新
    6. void update(Teacher t);
    7. // 根据id查询一个教师信息
    8. Teacher select(int id);
    9. // 查询所有教师信息
    10. List<Teacher> selectAll();

    }

  • TeacherDAOImpl 文件

    package com.yy.homework.dao.impl;

    import com.yy.homework.dao.ITeacherDAO;
    import com.yy.homework.domain.Teacher;
    import com.yy.homework.util.MybatisUtil;
    import org.apache.ibatis.session.SqlSession;

    import java.util.ArrayList;
    import java.util.List;

    / @program: Mybatis_test03 @ClassName TeacherDAOImpl @description: 实现接口中的方法 @author: YanYang * @create: 2021-04-17 22:19 /
    public class TeacherDAOImpl implements ITeacherDAO { 

    1. SqlSession sqlSession = null;
    3. @Override
    4. public void insert(Teacher t) { 
    5.     try { 
    6.         sqlSession = MybatisUtil.getInstance().openSession();
    7.         sqlSession.insert("com.yy.homework.mapper.TeacherMapper.insert", t);
    8.         sqlSession.commit();
    9.     } catch (Exception e) { 
    10.         e.printStackTrace();
    11.     } finally { 
    12.         sqlSession.close();
    13.     }
    14. }
    16. @Override
    17. public void delete(int id) { 
    18.     try { 
    19.         sqlSession = MybatisUtil.getInstance().openSession();
    20.         sqlSession.delete("com.yy.homework.mapper.TeacherMapper.delete", id);
    21.         sqlSession.commit();
    22.     } catch (Exception e) { 
    23.         e.printStackTrace();
    24.     } finally { 
    25.         sqlSession.close();
    26.     }
    27. }
    29. @Override
    30. public void update(Teacher t) { 
    31.     try { 
    32.         sqlSession = MybatisUtil.getInstance().openSession();
    33.         sqlSession.update("com.yy.homework.mapper.TeacherMapper.update", t);
    34.         sqlSession.commit();
    35.     } catch (Exception e) { 
    36.         e.printStackTrace();
    37.     } finally { 
    38.         sqlSession.close();
    39.     }
    41. }
    43. @Override
    44. public Teacher select(int id) { 
    45.     Teacher teacher = null;
    46.     try { 
    47.         sqlSession = MybatisUtil.getInstance().openSession();
    48.         teacher = sqlSession.selectOne("com.yy.homework.mapper.TeacherMapper.select", id);
    49.     } catch (Exception e) { 
    50.         e.printStackTrace();
    51.     } finally { 
    52.         sqlSession.close();
    53.     }
    54.     return teacher;
    55. }
    57. @Override
    58. public List<Teacher> selectAll() { 
    59.     List<Teacher> list = new ArrayList<>();
    60.     try { 
    61.         sqlSession = MybatisUtil.getInstance().openSession();
    62.         list = sqlSession.selectList("com.yy.homework.mapper.TeacherMapper.selectAll");
    63.     } catch (Exception e) { 
    64.         e.printStackTrace();
    65.     } finally { 
    66.         sqlSession.close();
    67.     }
    68.     return list;
    69. }

    }

  • Teacher 文件

    package com.yy.homework.domain;

    import lombok.*;

    import java.util.Date;

    / @program: Mybatis_test03 @ClassName Teacher @description: 教师JavaBean @author: YanYang * @create: 2021-04-17 22:12 /
    // @Setter @Getter @AllArgsConstructor @NoArgsConstructor @ToString
    public class Teacher { 

    1. private Integer userID;
    2. private String userName;
    3. private String sex;
    4. private Date birthYear;
    5. private String degree;
    6. private String title;
    7. private Date grade;
    8. private Integer collegeID;
    10. public Teacher() { 
    11. }
    12. public Teacher(Integer userID, String userName, String sex, Date birthYear, String degree, String title, Date grade, Integer collegeID) { 
    13.     this.userID = userID;
    14.     this.userName = userName;
    15.     this.sex = sex;
    16.     this.birthYear = birthYear;
    17.     this.degree = degree;
    18.     this.title = title;
    19.     this.grade = grade;
    20.     this.collegeID = collegeID;
    21. }
    22. @Override
    23. public String toString() { 
    24.     return "Teacher{" +
    25.             "userID=" + userID +
    26.             ", userName='" + userName + '\'' +
    27.             ", sex='" + sex + '\'' +
    28.             ", birthYear=" + birthYear +
    29.             ", degree='" + degree + '\'' +
    30.             ", title='" + title + '\'' +
    31.             ", grade=" + grade +
    32.             ", collegeID=" + collegeID +
    33.             '}';
    34. }
    35. public Integer getUserID() { 
    36.     return userID;
    37. }
    38. public void setUserID(Integer userID) { 
    39.     this.userID = userID;
    40. }
    41. public String getUserName() { 
    42.     return userName;
    43. }
    44. public void setUserName(String userName) { 
    45.     this.userName = userName;
    46. }
    47. public String getSex() { 
    48.     return sex;
    49. }
    50. public void setSex(String sex) { 
    51.     this.sex = sex;
    52. }
    53. public Date getBirthYear() { 
    54.     return birthYear;
    55. }
    56. public void setBirthYear(Date birthYear) { 
    57.     this.birthYear = birthYear;
    58. }
    59. public String getDegree() { 
    60.     return degree;
    61. }
    62. public void setDegree(String degree) { 
    63.     this.degree = degree;
    64. }
    65. public String getTitle() { 
    66.     return title;
    67. }
    68. public void setTitle(String title) { 
    69.     this.title = title;
    70. }
    71. public Date getGrade() { 
    72.     return grade;
    73. }
    74. public void setGrade(Date grade) { 
    75.     this.grade = grade;
    76. }
    77. public Integer getCollegeID() { 
    78.     return collegeID;
    79. }
    80. public void setCollegeID(Integer collegeID) { 
    81.     this.collegeID = collegeID;
    82. }

    }

  • TeacherMapper.xml 文件

    <?xml version=”1.0” encoding=”UTF-8” ?>
    <!DOCTYPE mapper

    1.     PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
    2.     "http://mybatis.org/dtd/mybatis-3-mapper.dtd">


    insert into Teacher (userName, sex, birthYear,degree, title, grade, collegeID) values (#{ userName},
    #{ sex}, #{ birthYear}, #{ degree}, #{ title}, #{ grade}, #{ collegeID})



    delete from Teacher where userID = #{ userID}



    update Teacher set userName = #{ userName}, sex = #{ sex}, birthYear = #{ birthYear}, degree = #{ degree},
    title = #{ title}, grade = #{ grade}, collegeID = #{ collegeID} where userID = #{ userID}

  • MybatisUtil 文件

    package com.yy.homework.util;

    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;

    / @program: Mybatis_test03 @ClassName MybatisUtil @description: 工具类 @author: YanYang * @create: 2021-04-17 22:20 /
    public class MybatisUtil { 

    1. /** * 单例模式 */
    2. private MybatisUtil() { }
    3. private static MybatisUtil mybatisUtil = new MybatisUtil();
    5. public static MybatisUtil getInstance() { 
    6.     return mybatisUtil;
    7. }
    9. private static SqlSessionFactory factory = null;
    10. static { 
    11.     try { 
    12.            // 获取 SqlSession 的工厂类
    13.         InputStream in = Resources.getResourceAsStream("mybatis-config.xml");
    14.         factory = new SqlSessionFactoryBuilder().build(in);
    15.     } catch (IOException e) { 
    16.         e.printStackTrace();
    17.     }
    18. }
    20. public SqlSession openSession() { 
    21.     // 获取 SqlSession 对象
    22.     return factory.openSession();
    23. }

    }

  • 测试类 文件

    package com.yy.homework.dao.impl.test;

    import com.yy.homework.dao.ITeacherDAO;
    import com.yy.homework.dao.impl.TeacherDAOImpl;
    import com.yy.homework.domain.Teacher;
    import org.junit.Test;

    import java.util.Date;

    import static org.junit.Assert.*;

    / @program: Mybatis_test03 @ClassName TeacherDAOImplTest @description: @author: YanYang * @create: 2021-04-18 11:52 /
    public class TeacherDAOImplTest { 

    1. ITeacherDAO td = new TeacherDAOImpl();
    2. @Test
    3. public void insert() { 
    4.     Teacher tc = new Teacher(null, "熊大", "公", new Date(), "博士", "森林管理员" ,new Date(), 2);
    5.     td.insert(tc);
    6. }
    8. @Test
    9. public void delete() { 
    10.     td.delete(10017);
    11. }
    13. @Test
    14. public void update() { 
    15.     Teacher tc = new Teacher(null, "熊大", "公", new Date(), "博士", "森林管理员" ,new Date(), 2);
    16.     tc.setUserID(10012);
    17.     td.update(tc);
    18. }
    20. @Test
    21. public void select() { 
    22.     td.select(1001);
    23. }
    25. @Test
    26. public void selectAll() { 
    27.     td.selectAll();
    28. }

    }

总结：

以上就是使用 Mybatis 实现简单增删改查了

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