MyBatis连接MySql数据库及使用教程(XML配置法)

以你之姓@ 2022-12-24 05:51 180阅读 0赞

### **MyBatis连接MySql数据库及使用教程(XML配置法)****还有一个注解开发法这里先不说** ###

**(推荐一个SSM框架不错的视频，B站狂神)**

**1.创建一个空白的maven项目**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM1NTAyMjA2_size_16_color_FFFFFF_t_70][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM1NTAyMjA2_size_16_color_FFFFFF_t_70 1][]

**2.打开项目的pom.xml文件(将下面代码粘贴进去，不用修改)**

<dependencies>
        
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <version>5.1.37</version>
            </dependency>
    
    
    
        
    
                <dependency>
                    <groupId>org.mybatis</groupId>
                    <artifactId>mybatis</artifactId>
                    <version>3.4.6</version>
                </dependency>
    
    
    
            
            <dependency>
                <groupId>junit</groupId>
                <artifactId>junit</artifactId>
                <version>4.13</version>
                <scope>test</scope>
            </dependency>
    
    
    
        </dependencies>
        
            <build>
                <resources>
                    <resource>
                        <directory>src/main/resources</directory>
                        <includes>
                            <include>**/*.properties</include>
                            <include>**/*.xml</include>
                        </includes>
                        <filtering>true</filtering>
                    </resource>
                    <resource>
                        <directory>src/main/java</directory>
                        <includes>
                            <include>**/*.properties</include>
                            <include>**/*.xml</include>
                        </includes>
                        <filtering>true</filtering>
                    </resource>
                </resources>
            </build>
    
        <properties>
            <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        </properties>

**3.创建一个名为mybatis-config空白的XML文件(在src/main/resources目录下创建)**

**需要修改：**

**url（url里面有一个test   这个是你要调用的那个数据库的名称）**

**username（ mysql登录账号）**

**password（mysql登录密码）**

<?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>
    
         <environments default="development">
           <environment id="development">
              <transactionManager type="JDBC"/>
              <dataSource type="POOLED">
                    <property name="driver" value="com.mysql.jdbc.Driver"/>
                    <property name="url" value="jdbc:mysql://localhost:3306/test?"/>
                    <property name="username" value="root"/>
                    <property name="password" value="Zjh520.1314."/>
              </dataSource>
              </environment>
    
             
          </environments>
    
    
    
        
    
        </configuration>

**4.创建MyBatisUtils工具类(在cn/utils 目录下创建)**

**先在src/main/java下创建一个包，取名叫cn，然后再cn下再创建三个包，名为 dao、pojo、utils   (创建包是为了更好的区分代码，使得自己更容易理解，不会乱)**

**如图：**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM1NTAyMjA2_size_16_color_FFFFFF_t_70 2][]

public class MyBatisUtils {
    
       private static SqlSessionFactory sqlSessionFactory;
    
        static {
    
    
    
            try {
                //使用 MyBatis获取SqlSessionFactory对象
                String resource = "mybatis-config.xml";
    
    
                InputStream   inputStream = Resources.getResourceAsStream(resource);
    
                 sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
    
            } catch (IOException e) {
                e.printStackTrace();
            }
    
        }
    
        //既然有了 SqlSessionFactory，顾名思义，我们就可以从中获得 SqlSession 的实例了。
        // SqlSession 完全包 含了面向数据库执行 SQL 命令所需的所有方法。
    
        public static SqlSession getSqlSession(){
           SqlSession sqlSession= sqlSessionFactory.openSession();
    
           return sqlSessionFactory.openSession();
        }
    
    }

**5.创建名为User的实体类（在cn/pojo 目录下创建）**

**首先我们打开mysql数据库，然后创一个名为test的数据库，再创建一张名为user的表，表里创建三个属性，id、name、password  (id为主键) ，在表里写下几条数据留着等下查询使用！**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM1NTAyMjA2_size_16_color_FFFFFF_t_70 3][]

//实体类
    public class User {
    
        private int id;
        private String name;
        private String password;
    
        public User(){}
    
        public User(int id,String name ,String password){
    
            this.id=id;
            this.name=name;
            this.password=password;
        }
    
        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 String getPassword() {
            return password;
        }
    
        public void setPassword(String password) {
            this.password = password;
        }
    
    
        @Override
        public String toString() {
            return "User{" +
                    "id=" + id +
                    ", name='" + name + '\'' +
                    ", password='" + password + '\'' +
                    '}';
        }
    }

**6.创建名为UserMapper的接口(在cn/dao 目录下创建**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM1NTAyMjA2_size_16_color_FFFFFF_t_70 4][]

public interface UserMapper {
    
        //获取全部用户
        List<User> getUserList();
    
    }

**7.创建名为UserMapper的XML文件(在cn/dao 目录下创建，我们的sql语句都是在这个文件里面完成的，将这段代码粘贴进UserMapper.xml）**

<?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="cn.dao.UserMapper">
    
    
        
        
        
    
        <select id="getUserList"  resultType="cn.pojo.User" >
         select * from test.user
        </select>
    
      
    </mapper>

** 注意：UserMapper.xml搞定之后，我们要去mybatis-config.xml里将以下代码粘贴进去(将UserMapper.xml的路径配置进mybatis-config.xml)**

**8.测试sql（在src/test下创建一个名为UserMapperTest测试类）**

public class UserMapperTest {
    
    
        @Test
        public void testAll(){
            //第一步   获取sqlsession对象
            SqlSession sqlSession=MyBatisUtils.getSqlSession();
            try {
    
                //第二步  执行sql
                UserMapper userMapper=sqlSession.getMapper(UserMapper.class);
                List<User> userList=userMapper.getUserList();
                for (User user:userList){
    
                    System.out.println("查询全部:"+user);
                }
    
            }catch (Exception e){
                e.printStackTrace();
            }finally {
                //第三步  关闭sqlSession
                sqlSession.close();
            }
    
    
    
    }
    
    
    
    
    }

**测试结果图：**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM1NTAyMjA2_size_16_color_FFFFFF_t_70 5][]

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