mybatis学习一：配置mybatis，使用SqlSession完成CURD

1、创建和数据库表相关的实体类：

public class User {

    private Integer id;
    private String name;
    private String username;
    private String password;
    private String gender;

    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 String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getGender() {
        return gender;
    }

    public void setGender(String gender) {
        this.gender = gender;
    }

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

2、pom.xml引入mybatis依赖：

<dependency>
    <groupId>org.mybatis</groupId>
    <artifactId>mybatis</artifactId>
    <version>3.4.6</version>
</dependency>

3、创建mybatis的配置文件：

注：mybatis配置文件里面的标签有顺序要求，不能胡乱写。

下面代码中，是所有标签的排列顺序，被注释掉的是一般用不到的标签。

<?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/>-->
    <settings>
        <!--用于配置sql运行时的日志输出，控制台可以输出当前执行的sql语句-->
        <setting name="logImpl" value="STDOUT_LOGGING"/>
    </settings>
    <!--用于给实体类配置别名-->
    <typeAliases>
        <typeAlias type="org.spring.teach.User" alias="User"/>
    </typeAliases>
    <!--<typeHandlers/>
    <objectFactory type=""/>
    <objectWrapperFactory type=""/>
    <reflectorFactory type=""/>-->
    <!--配置数据库环境，可以配置多个环境，尽管可以配置多个环境，每个 SqlSessionFactory 实例只能选择其一-->
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC" />
            <!-- 连接池的配置 -->
            <dataSource type="POOLED">
                <property name="driver" value="oracle.jdbc.OracleDriver" />
                <property name="url" value="jdbc:oracle:thin:@localhost:1521:orcl" />
                <property name="username" value="c##root" />
                <property name="password" value="c##root" />
            </dataSource>
        </environment>
    </environments>
    <!--<databaseIdProvider type=""/>-->
    <!-- 指定映射文件的位置 -->
    <mappers>
        <mapper resource="org/spring/teach/entity/UserMapper.xml" />
    </mappers>
</configuration>

4、创建映射文件：

<?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">
<!-- 映射文件 -->
<mapper namespace="test"></mapper>

5、书写sql：

<?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">
<!-- 映射文件 -->
<mapper namespace="test">
    <insert id="save" parameterType="User">
		insert into t_user values(t_user_seq.nextval,#{username},#{name},#{password},#{gender})
	</insert>

    <select id="findAll" resultType="User">
		select * from t_user
	</select>

    <select id="findById" parameterType="int" resultType="User">
        select * from t_user where id = #{id}<!-- 此处的id只是一个占位符，可随意 -->
    </select>
    <update id="update" parameterType="User">
        update t_user set username = #{username},name = #{name},password = #{password},gender = #{gender} where id = #{id}<!-- 此处的id只是一个占位符，可随意 -->
    </update>
    <delete id="delete" parameterType="int">
        delete from t_user where id = #{id1}<!-- 此处的id只是一个占位符，可随意 -->
    </delete>
</mapper>

6、测试：

public class TestCase {

    private SqlSession sqlSession;

    @Before
    public void before() {
        SqlSessionFactoryBuilder ssfb = new SqlSessionFactoryBuilder();
        SqlSessionFactory ssf = ssfb.build(TestCase.class.getClassLoader().getResourceAsStream("mybatisConfigure.xml"));
        sqlSession = ssf.openSession();
    }

    @After
    public void after() {
        sqlSession.commit();
        sqlSession.close();
    }

    @Test
    public void save() {
        User user = new User();
        user.setUsername("赵六");
        user.setName("赵六");
        user.setPassword("534634634");
        user.setGender("男");
        int row = sqlSession.insert("test.save", user);
        System.out.println(row);
    }

    @Test
    public void findAll() {
        List<User> list = sqlSession.selectList("test.findAll");
        System.out.println(list);
    }

    @Test
    public void findById() {
        User user = sqlSession.selectOne("test.findById", 1);
        System.out.println(user);
    }

    @Test
    public void update() {
        User user = new User();
        user.setId(62);
        user.setUsername("赵六");
        user.setName("赵六");
        user.setPassword("gfnvcvsdv");
        user.setGender("女");
        int row = sqlSession.update("test.update", user);
        System.out.println(row);
    }

    @Test
    public void delete() {
        int row = sqlSession.delete("test.delete", 64);
        System.out.println(row);
    }

}

[User{id=43, name='李四', username='lisi', password='123456', gender='女'}, User{id=1, name='张三', username='zhangsan', password='123456', gender='男'}, User{id=62, name='赵六', username='赵六', password='gfnvcvsdv', gender='女'}]

Process finished with exit code 0