二、MyBaits入门

流程：搭建环境->导入MyBaits->编写代码->测试

 

一、搭建环境

新键数据库及user表，并插入几条数据

CREATE DATABASE MyBaits;

USE MyBaits;


CREATE TABLE `user`(
	`id` INT UNSIGNED AUTO_INCREMENT,
	`name` VARCHAR(20),
	`pwd` VARCHAR(20),
	PRIMARY KEY(`id`)
)ENGINE=INNODB DEFAULT CHARSET= UTF8;

INSERT INTO `user`(`name`,`pwd`) VALUES ('zs','123456');
INSERT INTO `user`(`name`,`pwd`) VALUES ('ls','123456');
INSERT INTO `user`(`name`,`pwd`) VALUES ('ww','123456');

 

二、导入MyBaits

新键maven项目，父工程pom.xml如下：

<?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.zx</groupId>
    <artifactId>MyBaits3</artifactId>
    <packaging>pom</packaging>
    <version>1.0-SNAPSHOT</version>
    <modules>
        <module>MyBaits01</module>
    </modules>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>


    <dependencies>
        <!--MySQL connector-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.47</version>
        </dependency>

        <!--mybaits-->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.7</version>
        </dependency>

        <!--单元测试-->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.13.1</version>
            <scope>test</scope>
        </dependency>
    </dependencies>


    <build>
        <resources>
            <!--java-->
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
                <filtering>true</filtering>
            </resource>

            <!--resources-->
            <resource>
                <directory>src/main/resources</directory>
                <includes>
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
                <filtering>true</filtering>
            </resource>
        </resources>
    </build>


</project>

 

三、编写代码

1. 实体类user

public class User {

  private long id;
  private String name;
  private String pwd;


  public User() {
  }

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


  public long getId() {
    return id;
  }

  public void setId(long id) {
    this.id = id;
  }


  public String getName() {
    return name;
  }

  public void setName(String name) {
    this.name = name;
  }


  public String getPwd() {
    return pwd;
  }

  public void setPwd(String pwd) {
    this.pwd = pwd;
  }


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

2.  UserMapper接口

public interface UserMapper {

    public List<User> getList();
}

3. 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="com.zx.mapper.UserMapper">
    <select id="getList" resultType="com.zx.pojo.User">
        select * from `user`
    </select>

</mapper>

 4. MyBaitsUtils

public class MyBaitsUtils {

    private static SqlSessionFactory sqlSessionFactory;

    static {
        String resource = "mybatis-config.xml";
        InputStream inputStream = null;
        try {
            inputStream = Resources.getResourceAsStream(resource);
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
        sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
    }

    public static SqlSession getSqlSession(){
        return sqlSessionFactory.openSession();
    }
}

5. mybatis-config.xml

<?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>
        <property name="driver" value="com.mysql.jdbc.Driver"/>
        <property name="url" value="jdbc:mysql://localhost:3306/MyBaits?useSSL=true&amp;characterEncoding=utf8"/>
        <property name="username" value="root"/>
        <property name="password" value="123456"/>
    </properties>

    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
                <property name="driver" value="${driver}"/>
                <property name="url" value="${url}"/>
                <property name="username" value="${username}"/>
                <property name="password" value="${password}"/>
            </dataSource>
        </environment>
    </environments>

    <mappers>
        <mapper resource="com/zx/mapper/UserMapper.xml"/>
    </mappers>
</configuration>

 

四、测试

public class UserTest {

    @Test
    public void getList(){
        SqlSession sqlSession = MyBaitsUtils.getSqlSession();
        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
        List<User> list = userMapper.getList();
        for (User user : list) {
            System.out.println(user);
        }
        sqlSession.close();
    }

}

结果：