mybatis的示例代码

痛定思痛。 2023-09-23 16:35 133阅读 0赞

**目录**

前言：

一、示例代码图

二、代码例子

1.接口类--boyMapper

2.封装类--Boy

3.测试类---BoyTest

4.映射文件--boyMapper.xml

5.统一配置文件--mybatis-config.xml

6.依赖文件--pom.xml

7.数据库对应的表

## 前言： ##

[这是用来这篇文章的参考代码（超链接） ][Link 1]

## 一、示例代码图 ##

![a3a14827e00b4deea6763488f83965ea.png][]

## 二、代码例子 ##

### 1.接口类--boyMapper  ###

package com.project.Mapper;
    
    import com.project.pojo.Boy;
    
    import java.util.List;
    
    public interface boyMapper {
    
        //1.定义一个查询全部的方法
        //List<封装类> 查询全部的方法
       List<Boy>  selectAll();
    }

### 2.封装类--Boy ###

package com.project.pojo;
    
    public class Boy {
        private Integer id;
    
        private String name;
    
        private Integer age;
    
        public Integer getId() {
            return id;
        }
    
        public void setId(Integer id) {
            this.id = id;
        }
    
        public String getName() {
            return name;
        }
    
        public void setName(String name) {
            this.name = name;
        }
    
        public Integer getAge() {
            return age;
        }
    
        public void setAge(Integer age) {
            this.age = age;
        }
    
        public Boy(Integer id, String name, Integer age) {
            this.id = id;
            this.name = name;
            this.age = age;
        }
    
        public Boy() {
        }
    
        @Override
        public String toString() {
            return "boy{" +
                    "id=" + id +
                    ", name='" + name + '\'' +
                    ", age=" + age +
                    '}';
        }
    }

### 3.测试类---BoyTest ###

package com.project.pojo;
    
    import com.project.Mapper.boyMapper;
    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 BoyTest {
        public static void main(String[] args) throws IOException {
            //1.加载mybatis连接文件（核心配置文件）
            String resource = "mybatis-config.xml";//这是连接数据库的统一配置xml文件
            InputStream inputStream = Resources.getResourceAsStream(resource);//固定写法
            SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);//固定写法
    
            //2.获取SqlSessionFactory对象--固定写法
            SqlSession sqlSession = sqlSessionFactory.openSession();
    
            //3.执行sql语句
            //接口 自定义接口名 = sqlSession.getMapper(接口.class);
            boyMapper boyMapper = sqlSession.getMapper(boyMapper.class);
    
            //接口里面的方法
            List<Boy> boyAll = boyMapper.selectAll();
    
            //4.打印语句
            System.out.println(boyAll);
    
            //5.释放资源--固定写法
            sqlSession.close();
        }
    }

### 4.映射文件--boyMapper.xml ###

<?xml version="1.0" encoding="UTF-8" ?>
    <!DOCTYPE mapper
            PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
            "https://mybatis.org/dtd/mybatis-3-mapper.dtd">
    
    
    <mapper namespace="com.project.Mapper.boyMapper">
        <select id="selectAll" resultType="com.project.pojo.Boy">
            select * from boy;
        </select>
    </mapper>

### 5.统一配置文件--mybatis-config.xml ###

<?xml version="1.0" encoding="UTF-8" ?>
    <!DOCTYPE configuration
            PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
            "https://mybatis.org/dtd/mybatis-3-config.dtd">
    <configuration>
        <environments default="development">
            <environment id="development">
                <transactionManager type="JDBC"/>
                <dataSource type="POOLED">
                    
                    <property name="driver" value="com.mysql.cj.jdbc.Driver"/>
                    <property name="url" value="jdbc:mysql://localhost:3306/javafx"/>
                    <property name="username" value="root"/>
                    <property name="password" value="123456"/>
                </dataSource>
            </environment>
        </environments>
        <mappers>
            
            <mapper resource="com/project/Mapper/boyMapper.xml"/>
        </mappers>
    </configuration>

### 6.依赖文件--pom.xml ###

<?xml version="1.0" encoding="UTF-8"?>
    <project xmlns="http://maven.apache.org/POM/4.0.0"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
        <modelVersion>4.0.0</modelVersion>
        
        <groupId>org.example</groupId>
        <artifactId>maven-java</artifactId>
        <version>1.0-SNAPSHOT</version>
        <packaging>war</packaging>
    
        <properties>
            <maven.compiler.source>17</maven.compiler.source>
            <maven.compiler.target>17</maven.compiler.target>
        </properties>
        
    
        <dependencies>
            
            <dependency>
                <groupId>org.mybatis</groupId>
                <artifactId>mybatis</artifactId>
                <version>3.5.11</version>
            </dependency>
    
            
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <version>8.0.30</version>
            </dependency>
        </dependencies>
    
    </project>

### 7.数据库对应的表 ###

![854f4c881188445590ec1f51f0c93af9.png][]

[Link 1]: https://blog.csdn.net/m0_52861000/article/details/128039296?spm=1001.2014.3001.5502
[a3a14827e00b4deea6763488f83965ea.png]: https://img-blog.csdnimg.cn/a3a14827e00b4deea6763488f83965ea.png
[854f4c881188445590ec1f51f0c93af9.png]: https://img-blog.csdnimg.cn/854f4c881188445590ec1f51f0c93af9.png