Mybatis实现简单增删改查

朱雀 2023-01-13 10:44 250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][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][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3p6dmFy_size_16_color_FFFFFF_t_70]

## 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
            PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
            "http://mybatis.org/dtd/mybatis-3-config.dtd">
    <configuration>
        <properties resource="db.properties"/>
        
        <typeAliases>
            <package name="com.yy.homework.domain"/>
        </typeAliases>
    
        <environments default="dev">
            <environment id="dev">
                <transactionManager type="JDBC"/>
                <dataSource type="POOLED">
                    <property name="driver" value="${db.driverClassName}"/>
                    <property name="url" value="${db.url}"/>
                    <property name="username" value="${db.username}"/>
                    <property name="password" value="${db.password}"/>
                </dataSource>
            </environment>
        </environments>
    
        <mappers>
            <mapper resource="com/yy/homework/mapper/TeacherMapper.xml"/>
        </mappers>
    </configuration>

*  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 { 
    	// 增加
        void insert(Teacher t);
    	// 删除
        void delete(int id);
    	// 更新
        void update(Teacher t);
    	// 根据id查询一个教师信息
        Teacher select(int id);
    	// 查询所有教师信息
        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 { 
        SqlSession sqlSession = null;
    
        @Override
        public void insert(Teacher t) { 
            try { 
                sqlSession = MybatisUtil.getInstance().openSession();
                sqlSession.insert("com.yy.homework.mapper.TeacherMapper.insert", t);
                sqlSession.commit();
            } catch (Exception e) { 
                e.printStackTrace();
            } finally { 
                sqlSession.close();
            }
        }
    
        @Override
        public void delete(int id) { 
            try { 
                sqlSession = MybatisUtil.getInstance().openSession();
                sqlSession.delete("com.yy.homework.mapper.TeacherMapper.delete", id);
                sqlSession.commit();
            } catch (Exception e) { 
                e.printStackTrace();
            } finally { 
                sqlSession.close();
            }
        }
    
        @Override
        public void update(Teacher t) { 
            try { 
                sqlSession = MybatisUtil.getInstance().openSession();
                sqlSession.update("com.yy.homework.mapper.TeacherMapper.update", t);
                sqlSession.commit();
            } catch (Exception e) { 
                e.printStackTrace();
            } finally { 
                sqlSession.close();
            }
    
        }
    
        @Override
        public Teacher select(int id) { 
            Teacher teacher = null;
            try { 
                sqlSession = MybatisUtil.getInstance().openSession();
                teacher = sqlSession.selectOne("com.yy.homework.mapper.TeacherMapper.select", id);
            } catch (Exception e) { 
                e.printStackTrace();
            } finally { 
                sqlSession.close();
            }
            return teacher;
        }
    
        @Override
        public List<Teacher> selectAll() { 
            List<Teacher> list = new ArrayList<>();
            try { 
                sqlSession = MybatisUtil.getInstance().openSession();
                list = sqlSession.selectList("com.yy.homework.mapper.TeacherMapper.selectAll");
            } catch (Exception e) { 
                e.printStackTrace();
            } finally { 
                sqlSession.close();
            }
            return list;
        }
    }

*  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 { 
        private Integer userID;
        private String userName;
        private String sex;
        private Date birthYear;
        private String degree;
        private String title;
        private Date grade;
        private Integer collegeID;
    
        public Teacher() { 
        }
        public Teacher(Integer userID, String userName, String sex, Date birthYear, String degree, String title, Date grade, Integer collegeID) { 
            this.userID = userID;
            this.userName = userName;
            this.sex = sex;
            this.birthYear = birthYear;
            this.degree = degree;
            this.title = title;
            this.grade = grade;
            this.collegeID = collegeID;
        }
        @Override
        public String toString() { 
            return "Teacher{" +
                    "userID=" + userID +
                    ", userName='" + userName + '\'' +
                    ", sex='" + sex + '\'' +
                    ", birthYear=" + birthYear +
                    ", degree='" + degree + '\'' +
                    ", title='" + title + '\'' +
                    ", grade=" + grade +
                    ", collegeID=" + collegeID +
                    '}';
        }
        public Integer getUserID() { 
            return userID;
        }
        public void setUserID(Integer userID) { 
            this.userID = userID;
        }
        public String getUserName() { 
            return userName;
        }
        public void setUserName(String userName) { 
            this.userName = userName;
        }
        public String getSex() { 
            return sex;
        }
        public void setSex(String sex) { 
            this.sex = sex;
        }
        public Date getBirthYear() { 
            return birthYear;
        }
        public void setBirthYear(Date birthYear) { 
            this.birthYear = birthYear;
        }
        public String getDegree() { 
            return degree;
        }
        public void setDegree(String degree) { 
            this.degree = degree;
        }
        public String getTitle() { 
            return title;
        }
        public void setTitle(String title) { 
            this.title = title;
        }
        public Date getGrade() { 
            return grade;
        }
        public void setGrade(Date grade) { 
            this.grade = grade;
        }
        public Integer getCollegeID() { 
            return collegeID;
        }
        public void setCollegeID(Integer collegeID) { 
            this.collegeID = collegeID;
        }
    }

*  TeacherMapper.xml 文件

<?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="com.yy.homework.mapper.TeacherMapper">
        <insert id="insert">
            insert into Teacher (userName, sex, birthYear,degree, title, grade, collegeID) values (#{ userName},
            #{ sex}, #{ birthYear}, #{ degree}, #{ title}, #{ grade}, #{ collegeID})
        </insert>
    
        <delete id="delete">
            delete from Teacher where userID = #{ userID}
        </delete>
    
        <update id="update">
            update Teacher set userName = #{ userName}, sex = #{ sex}, birthYear = #{ birthYear}, degree = #{ degree},
            title = #{ title}, grade = #{ grade}, collegeID = #{ collegeID} where userID = #{ userID}
        </update>
    
        <select id="select" resultType="Teacher">
            select * from teacher where userID = #{ id}
        </select>
    
        <select id="selectAll" resultType="Teacher">
            select * from teacher
        </select>
    </mapper>

*  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 { 
    	/** * 单例模式 */
        private MybatisUtil() { }
        private static MybatisUtil mybatisUtil = new MybatisUtil();
    
        public static MybatisUtil getInstance() { 
            return mybatisUtil;
        }
    
        private static SqlSessionFactory factory = null;
        static { 
            try { 
           		// 获取 SqlSession 的工厂类
                InputStream in = Resources.getResourceAsStream("mybatis-config.xml");
                factory = new SqlSessionFactoryBuilder().build(in);
            } catch (IOException e) { 
                e.printStackTrace();
            }
        }
    
        public SqlSession openSession() { 
        	// 获取 SqlSession 对象
            return factory.openSession();
        }
    
    }

*  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 { 
        ITeacherDAO td = new TeacherDAOImpl();
        @Test
        public void insert() { 
            Teacher tc = new Teacher(null, "熊大", "公", new Date(), "博士", "森林管理员" ,new Date(), 2);
            td.insert(tc);
        }
    
        @Test
        public void delete() { 
            td.delete(10017);
        }
    
        @Test
        public void update() { 
            Teacher tc = new Teacher(null, "熊大", "公", new Date(), "博士", "森林管理员" ,new Date(), 2);
            tc.setUserID(10012);
            td.update(tc);
        }
    
        @Test
        public void select() { 
            td.select(1001);
        }
    
        @Test
        public void selectAll() { 
            td.selectAll();
        }
    }

# 总结： #

以上就是使用 Mybatis 实现简单增删改查了

[https_blog.csdn.net_zzvar_article_details_115831533]: https://blog.csdn.net/zzvar/article/details/115831533
[3aa3d2090bb6b329fa23897922c8ec47.png]: /images/20221022/631b071262f345e98df8122ab0c3ddc3.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3p6dmFy_size_16_color_FFFFFF_t_70]: /images/20221022/3bbeb513f7894e63a7f463f06cd834ac.png