Mybatis入门第一个程序--->及注意事项

 1 <?xml version="1.0" encoding="UTF-8"?>
 2 <project xmlns="http://maven.apache.org/POM/4.0.0"
 3          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 4          xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
 5     <modelVersion>4.0.0</modelVersion>
 6 <!--    父工程-->
 7     <groupId>org.example</groupId>
 8     <artifactId>Maven04</artifactId>
 9     <packaging>pom</packaging>
10     <version>1.0-SNAPSHOT</version>
11     <modules>
12         <module>Maven4</module>
13     </modules>
14     <!--依赖-->
15     <dependencies>
16         <dependency>
17             <groupId>mysql</groupId>
18             <artifactId>mysql-connector-java</artifactId>
19             <version>8.0.18</version>
20         </dependency>
21         <dependency>
22             <groupId>junit</groupId>
23             <artifactId>junit</artifactId>
24             <version>4.9</version>
25         </dependency>
26         <dependency>
27             <groupId>org.mybatis</groupId>
28             <artifactId>mybatis</artifactId>
29             <version>3.5.5</version>
30         </dependency>
31     </dependencies>
32 
33     <build>
34         <resources>
35             <resource>
36                 <directory>src/main/java</directory>
37                 <includes>
38                     <include>**/*.properties</include>
39                     <include>**/*.xml</include>
40                 </includes>
41                 <filtering>true</filtering>
42             </resource>
43             <resource>
44                 <directory>src/main/resources</directory>
45                 <includes>
46                     <include>**/*.properties</include>
47                     <include>**/*.xml</include>
48                 </includes>
49                 <filtering>true</filtering>
50             </resource>
51         </resources>
52     </build>
53 
54 </project>

 1 <?xml version="1.0" encoding="UTF-8" ?>
 2 <!DOCTYPE configuration
 3         PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
 4         "http://mybatis.org/dtd/mybatis-3-config.dtd">
 5 <configuration>
 6     <environments default="development">
 7         <environment id="development">
 8             <transactionManager type="JDBC"/>
 9             <dataSource type="POOLED">
10                 <property name="driver" value="com.mysql.cj.jdbc.Driver"/>
11                 <property name="url" value="jdbc:mysql://localhost:3306/testdb?serverTimezone=UTC&amp;useSSL=true&amp;useUnicode=true&amp;characterEncoding=UTF-8"/>
12                 <property name="username" value="root"/>
13                 <property name="password" value="123456"/>
14             </dataSource>
15         </environment>
16     </environments>
17 
18     <mappers>
19         <mapper resource="com/xian/dao/UserMapper.xml"/>
20     </mappers>
21 </configuration>

 1 package com.xian.utils;
 2 
 3 import org.apache.ibatis.io.Resources;
 4 import org.apache.ibatis.session.SqlSession;
 5 import org.apache.ibatis.session.SqlSessionFactory;
 6 import org.apache.ibatis.session.SqlSessionFactoryBuilder;
 7 
 8 import java.io.IOException;
 9 import java.io.InputStream;
10 
11 public class MybatisUtils {
12     private  static SqlSessionFactory sqlSessionFactory;
13     static {
14 
15         try {
16             String resource = "mybatis-config.xml";
17             InputStream inputStream = Resources.getResourceAsStream(resource);
18             sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
19 
20         } catch (IOException e) {
21             e.printStackTrace();
22         }
23     }
24     public static SqlSession getSqlsession(){
25         return sqlSessionFactory.openSession();
26     }
27 }

package com.xian.pojo;

public class User {
    int id;
    String name;

    public User() {
    }

    public User(int id, String name) {
        this.id = id;
        this.name = name;
    }

    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;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", name=‘" + name + ‘\‘‘ +
                ‘}‘;
    }
}

package com.xian.dao;

import com.xian.pojo.User;

import java.util.List;

public interface UserMapper {
    List<User> getUserList();
}

1 <?xml version="1.0" encoding="UTF-8" ?>
2 <!DOCTYPE mapper
3         PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
4         "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
5 <mapper namespace="com.xian.dao.UserMapper">
6     <select id="getUserList" resultType="com.xian.pojo.User">
7     select * from testdb.test001
8   </select>
9 </mapper>

 1 package com.xian.dao;
 2 
 3 import com.xian.pojo.User;
 4 import com.xian.utils.MybatisUtils;
 5 import org.apache.ibatis.session.SqlSession;
 6 import org.junit.Test;
 7 
 8 import java.util.List;
 9 
10 public class test {
11     @Test
12     public void test001(){
13         SqlSession sqlsession = MybatisUtils.getSqlsession();
14         UserMapper mapper = sqlsession.getMapper(UserMapper.class);
15         List<User> userList = mapper.getUserList();
16         for (User user : userList) {
17             System.out.println(user);
18         }
19         sqlsession.close();
20     }
21 }