Spring系列教程1.1-Mybites--示例工程

一 创建工程

1.1 依赖项的配置

使用idea创建一个空的Maven工程，可以按照如下示例创建

image-20240918144533578

/pom.xml

在 <dependencies>节点下中添加如下依赖项，然后更新Maven依赖

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25

<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>8.0.28</version>
</dependency>
<!--mybatis-->
<dependency>
    <groupId>org.mybatis</groupId>
    <artifactId>mybatis</artifactId>
    <version>3.5.6</version>
</dependency>
<!--junit-->
<dependency>
    <groupId>junit</groupId>
    <artifactId>junit</artifactId>
    <version>4.13.1</version>
</dependency>
<dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
    <version>1.18.32</version>
    <scope>provided</scope>
</dependency>

1.2 测试数据库

本例使用MySQL80作为数据库，请在你的数据库使用如下SQL语句创建数据库和数据表

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
create database d_mybatislearn;
use d_mybatislearn;
create table t_users(
                        uid int primary key auto_increment,
                        uname varchar(20) not null,
                        uage int not null,
                        usex int not null
);
insert into t_users
(uid,uname,uage,usex)
values
    (10001,"张三",19,1),
    (10002,"李四",25,1),
    (10003,"王美",21,0),
    (10004,"张梅",19,0);

1.2 配置文件

Mybatis核心配置文件

src/main/resources/mybatis-config.xml

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
<configuration>
    <!--    引入外部配置文件-->
    <properties resource="db.dev.properties"/>
    <!--    默认环境为dev-->
    <environments default="dev">
        <environment id="dev">
            <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
                <property name="driver" value="${mysql.driver}"/>
                <property name="url" value="${mysql.url}"/>
                <property name="username" value="${mysql.username}"/>
                <property name="password" value="${mysql.password}"/>
            </dataSource>
        </environment>
    </environments>
</configuration>

数据源配置文件

src/main/resources/db.properies

1
2
3
4
5
6
7
8
# mysql驱动,版本>=80添加cj
mysql.driver=com.mysql.cj.jdbc.Driver
# 数据库连接地址，
mysql.url=jdbc:mysql://localhost:3306/d_mybiteslearnserverTimezone=UTC&characterEncoding=utf8&useUnicode=true&useSSL=false
# 数据库用户名
mysql.username=root
# 数据库密码
mysql.password=root

1.3 相关代码

DAO类

src/main/java/site/icefox/javaeelearn/Dao/UsersDao.java

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
package site.icefox.javaeelearn.Dao;

import org.apache.ibatis.session.SqlSession;
import site.icefox.javaeelearn.Entity.UsersEntity;
import site.icefox.javaeelearn.Mapper.UsersMapper;
import site.icefox.javaeelearn.Util.DBConn;

import java.util.List;
import java.util.logging.Logger;

public class UsersDao {
    static Logger logger = Logger.getLogger(UsersDao.class.getName());

    public static UsersEntity getUsersByUid(int uid) {
        UsersEntity result = null;

        try (SqlSession sqlSession = DBConn.getSqlSession()) {
            UsersMapper usersmapper = sqlSession.getMapper(UsersMapper.class);
            result = usersmapper.getUserByUid(uid);
        } catch (Exception e) {
            logger.severe(e.getMessage());
        }
        return result;
    }

    public static List<UsersEntity> getAllUsers() {
        List<UsersEntity> result = null;
        try (SqlSession sqlSession = DBConn.getSqlSession()) {
            UsersMapper usersmapper = sqlSession.getMapper(UsersMapper.class);
            result = usersmapper.getUsers();
        } catch (Exception e) {
            logger.severe(e.getMessage());
        }
        return result;
    }
}

实体类

src/main/java/site/icefox/javaeelearn/Entity/UsersEntity.java

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
package site.icefox.javaeelearn.Entity;

import lombok.Data;

// Lombok 是一个 Java 库，它通过使用注解来帮助消除 Java  boilerplate 代码。
// 你可以在实体类上使用@Data注解，就不需要自己写getter 、 setter 以及 toString 方法了
@Data
public class UsersEntity {
    private Integer uid;
    private String uname;
    private Integer uage;
    private Integer usex;


    //  getter 、 setter 以及 toString 方法
    //  如果不使用@Data注解，请取消注释下面的代码
//    public Integer uid() {
//        return uid;
//    }
//
//    public void setUid(Integer uid) {
//        this.uid = uid;
//    }
//
//    public String uname() {
//        return uname;
//    }
//
//    public void setUname(String uname) {
//        this.uname = uname;
//    }
//
//    public Integer uage() {
//        return uage;
//    }
//
//    public void setUage(Integer uage) {
//        this.uage = uage;
//    }
//
//    public Integer usex() {
//        return usex;
//    }
//
//    public void setUsex(Integer usex) {
//        this.usex = usex;
//    }
//
//    @Override
//    public String toString() {
//        return "UsersEntity{" +
//                "uid=" + uid +
//                ", uname='" + uname + '\'' +
//                ", uage=" + uage +
//                ", usex=" + usex +
//                '}';
//    }
}

Mapper接口

src/main/java/site/icefox/javaeelearn/Mapper/UsersMapper.java

1
2
3
4
5
6
7
8
9
10
11
package site.icefox.javaeelearn.Mapper;

import site.icefox.javaeelearn.Entity.UsersEntity;

import java.util.List;

public interface UsersMapper {
    UsersEntity getUserByUid(int uid);
    List<UsersEntity> getUsers();
}

数据连接池工具类

src/main/java/site/icefox/javaeelearn/Util/DBConn.java

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
package site.icefox.javaeelearn.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;

public class DBConn {
    private static SqlSessionFactory sqlSessionFactory;
    //使用mybatis第一步，获取sqlSessionFactory对象
    static {
        try {
            String resource = "mybatis-config.xml";
            InputStream inputStream = Resources.getResourceAsStream(resource);
            sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        } catch (IOException e) {
            System.out.println(e.getMessage());
        }
    }
    public static SqlSession getSqlSession(){
        return sqlSessionFactory.openSession();
    }
}

二 测试

测试类

src/test/java/FirstProjectTest.java

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;
import site.icefox.javaeelearn.Dao.UsersDao;
import site.icefox.javaeelearn.Entity.UsersEntity;
import site.icefox.javaeelearn.Mapper.UsersMapper;
import site.icefox.javaeelearn.Util.DBConn;

public class FirstProjectTest {

    @Test
    public void queryOneUserByUidTest() {
        System.out.println(UsersDao.getUsersByUid(10001));
    }

    @Test
    public void queryUserListTest() {
        System.out.println(UsersDao.getAllUsers());
    }
}

测试结果

理应如下

image-20240919130352984

image-20240919130423688

三 结语

此工程仅用来展示Mybites的工作流程，详细内容稍后介绍。