[开发工具]Mybatis注解开发---实现增删改查

1. 新建maven项目

导入依赖

在porn.xml中写入依赖

<!--mybatis坐标-->
<dependency>
    <groupId>org.mybatis</groupId>
    <artifactId>mybatis</artifactId>
    <version>3.4.5</version>
</dependency>
<!--mysql驱动坐标-->
<dependency>    
    <groupId>mysql</groupId>   
    <artifactId>mysql-connector-java</artifactId>    
    <version>5.1.6</version>    
    <scope>runtime</scope>
</dependency>
<!--单元测试坐标-->
<dependency>    
    <groupId>junit</groupId>    
    <artifactId>junit</artifactId>    
    <version>4.12</version>    
    <scope>test</scope>
</dependency>

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2. 创建user数据表

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3. 编写User实体类

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?4. 编写UserMapper

public interface UserMapper {
    
    @Insert("insert into user values (#{id},#{username},#{password}")
    public void save(User user);

    @Update("update user set username=#{username},password=#{password} where id=#{id}")
    public void update(User user);

    @Delete("delete from user where id=#{id}")
    public void delete(int id);

    @Select("select * from user where id=#{id}")
    public User findById(int id);

    @Select("select * from user")
    public List<User> findAll();
}

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5. 编写核心文件SqlMapConfig.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>

    <!--通过properties便签加载外部的properties文件-->
    <properties resource="jdbc.properties"></properties>

    <!--数据源环境-->
    <environments default="developement">
        <environment id="developement">
            <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
                <property name="driver" value="${jdbc.driver}"/>
                <property name="url" value="${jdbc.url}"/>
                <property name="username" value="${jdbc.username}"/>
                <property name="password" value="${jdbc.password}"/>
            </dataSource>
        </environment>
    </environments>

    <!--加载映射关系-->
    <mappers>
        <!--指定接口所在的包-->
        <package name="com.demo.mapper"/>
    </mappers>

</configuration>

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6. 编写jdbc.properties

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7. 编写测试类

public class MybatisTest {

    private UserMapper mapper;
    @Before
    public void before() throws IOException {
        InputStream resourceAsStream = Resources.getResourceAsStream("sqlMapConfig.xml");
        SqlSessionFactory build = new SqlSessionFactoryBuilder().build(resourceAsStream);
        SqlSession sqlSession = build.openSession(true);
        mapper = sqlSession.getMapper(UserMapper.class);

    }

    @Test
    public void testSave(){
        User user = new User();
        user.setUsername("tom");
        user.setPassword("123");
        mapper.save(user);
    }

    @Test
    public void testUpdate(){
        User user = new User();
        user.setId(10);
        user.setUsername("tom123");
        user.setPassword("321");
        mapper.update(user);
    }

    @Test
    public void testDelete(){
        User user = new User();
        mapper.delete(10);
    }

    @Test
    public void testFindById(){
        User user = mapper.findById(2);
        System.out.println(user);
    }

    @Test
    public void testFindAll(){
        List<User> all = mapper.findAll();
        for (User user : all) {
            System.out.println(user);
        }
    }
}