JAVAEE架構技術之10-myBatis注解式開發

Mybatis注解開發

注解開發隻需要寫mapper接口即可，無需再書寫對應的xxMapper.xml映射檔案

對于單表操作還是比較友善的，但對多表操作就維護起來就比較麻煩了

資料庫準備

添加依賴

<!--lombok-->
<dependency>
  <groupId>org.projectlombok</groupId>
  <artifactId>lombok</artifactId>
  <version>1.18.12</version>
  <scope>provided</scope>
</dependency>

<!-- mybatis -->
<dependency>
  <groupId>org.mybatis</groupId>
  <artifactId>mybatis</artifactId>
  <version>3.5.6</version>
</dependency>
<!-- mysql驅動 -->
<dependency>
  <groupId>mysql</groupId>
  <artifactId>mysql-connector-java</artifactId>
  <version>5.1.16</version>
</dependency>
<!-- 測試用例 -->
<dependency>
  <groupId>junit</groupId>
  <artifactId>junit</artifactId>
  <version>4.12</version>
</dependency>
<!-- 日志 -->
<dependency>
  <groupId>org.slf4j</groupId>
  <artifactId>slf4j-log4j12</artifactId>
  <version>1.6.4</version>
</dependency>

核心配置檔案

<?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>
    <!-- 引入外部的配置檔案 -->
    <properties resource="jdbc.properties"/>
    <!-- 開啟駝峰比對 -->
    <settings>
        <setting name="mapUnderscoreToCamelCase" value="true"/>
    </settings>

    <!-- 連接配接資料庫相關的配置  後面不用寫，spring代替-->
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
                <property name="driver" value="${driverClass}"/>
                <property name="url" value="${url}"/>
                <property name="username" value="${jdbc.username}"/>
                <property name="password" value="${jdbc.password}"/>
            </dataSource>
        </environment>
    </environments>

    <mappers>
        <package name="cn.yanqi.mapper"/>
    </mappers>

</configuration>

jdbc.properties

driverClass=com.mysql.jdbc.Driver
url=jdbc:mysql:///mybatis
jdbc.username=root
jdbc.password=root

單表操作

實體類

@Data
public class User {
    private Long id;
    // 使用者名
    private String userName;
    // 密碼
    private String password;
    // 姓名
    private String name;
    // 年齡
    private Integer age;
    // 性别，1男性，2女性
    private Integer sex;
    // 出生日期
    private Date birthday;
    // 建立時間
    private Date created;
    // 更新時間
    private Date updated;
}

Mapper接口

/**
 * @Auther: yanqi
 * @Date:
 * @Dese:
 */
public interface UserMapper {

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

    @Select("select * from tb_user")
    List<User> selectAll();

    @Insert("INSERT INTO tb_user(id, user_name, password, name, age, sex, birthday, created, updated) VALUES (null,#{userName},#{password},#{name},#{age},#{sex},#{birthday},#{created},#{updated})")
    void adduser(User user);

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

    @Update("update tb_user set user_name =#{userName} ,  updated = #{updated} where id =#{id}")
    void updateuser(User user);
    
}

測試

/**
 * @Auther: yanqi
 * @Date:
 * @Dese:
 */
public class UserMapperTest {

    private UserMapper userMapper;
    private SqlSession sqlSession ;
    private SqlSessionFactory sqlSessionFactory ;


    @Before
    public void setUp() throws Exception {
        String resource = "mybatis-config.xml";
        InputStream inputStream = Resources.getResourceAsStream(resource);
        sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        sqlSession = sqlSessionFactory.openSession();
        userMapper = sqlSession.getMapper(UserMapper.class);
    }

    /**
     * 查詢單個
     */
    @Test
    public void select() {
        User user = this.userMapper.findById(1);
        System.out.println(user);

    }

    /**
     * 查詢所有
     */
    @Test
    public void selectAll() {
        List<User> users = this.userMapper.selectAll();
        for(User user : users){
            System.out.println(user);
        }
    }

    /**
     * 添加
     */
    @Test
    public void adduser() {
        User user = new User();
        user.setUserName("小江江");
        user.setPassword("123");
        user.setName("一燕");
        user.setAge(27);
        user.setSex(2);
        user.setBirthday(new Date());
        user.setCreated(new Date());
        user.setUpdated(new Date());

        this.userMapper.adduser(user);
        this.sqlSession.commit();
    }

    /**
     * 删除
     */
    @Test
    public void delete() {
        this.userMapper.delete(114);
        this.sqlSession.commit();
    }

    /**
     * 修改
     */
    @Test
    public void updateuser() {
        User user = new User();
        user.setId(118L);
        user.setUserName("哈哈2");
        user.setUpdated(new Date());

        this.userMapper.updateuser(user);
        this.sqlSession.commit();
    }
}

一對一

實體類

/**
 * 訂單表
 */
@Data
public class Order {
    private Integer id;
    private Long userId;
    private String orderNumber;

    private User user;
}

Mapper接口

/**
 * @Auther: yanqi
 * @Dese: OrderMapper接口 實作一對一
 */
public interface OrderMapper {

    /**
     * 查詢訂單，并且查詢出下單人的資訊
     * @param
     * @return
     */
    @Select("select * from tb_order where order_number = #{orderNum}")
    @Results({
            /*映射user
                column:   order表中user_id外鍵，傳遞給UserMapper.findById的id
                property: order實體類中的user字段
             */
            @Result(
                    column = "id",
                    property ="user",
                    javaType = User.class,
                    one = @One(select = "cn.yanqi.mapper.UserMapper.findById"))
            })
    List<Order> oneToOne(String orderNum);
}

public interface UserMapper {

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

測試

/**
 * @Auther: yanqi
 * @Date:
 * @Dese:
 */
public class UserMapperTest {

    private UserMapper userMapper;
    private OrderMapper orderMapper;
    private SqlSession sqlSession ;
    private SqlSessionFactory sqlSessionFactory ;


    @Before
    public void setUp() throws Exception {
        String resource = "mybatis-config.xml";
        InputStream inputStream = Resources.getResourceAsStream(resource);
        sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        sqlSession = sqlSessionFactory.openSession();
        userMapper = sqlSession.getMapper(UserMapper.class);
        orderMapper = sqlSession.getMapper(OrderMapper.class);

    }

    /**
     * 測試一對一
     */
    @Test
    public void oneToOne(){
        List<Order> orders = this.orderMapper.oneToOne("20200921002");
        for(Order order : orders){
            System.out.println(order);
        }
    }

一對多

實體類

/**
 * 訂單表
 * 
 */
@Data
public class Order {
    private Integer id;
    private Long userId;
    private String orderNumber;

    private User user;

    private List<Orderdetail> orderdetails;
}

@Data
public class Orderdetail {
    private Integer id;
    private Double totalPrice;
    private Integer status;
}

Mapper接口

/**
 * @Auther: yanqi
 * @Date:
 * @Dese:
 */
public interface OrderMapper {

 /**
     * 查詢訂單，查詢出下單人資訊并且查詢出訂單詳情。
     */
    @Select("select * from tb_order where order_number = #{orderNum}")
    @Results({
            /*映射user*/
            @Result(column = "id",
                    property ="user",
                    javaType = User.class,
                    one = @One(select = "cn.yanqi.mapper.UserMapper.findById")),
            /*映射orderdetails*/
            @Result(column = "id",
                    property = "orderdetails",
                    javaType =List.class,
                    many = @Many(select = "cn.yanqi.mapper.OrderDetailMapper.findById"))
    })
    List<Order> oneToMany(String orderNum);
}

/**
 * @Auther: yanqi
 */
public interface OrderDetailMapper {
    /**
     * 根據id查詢訂單詳情
     * @param id
     */
    @Select("select * from tb_orderdetail where id = #{id}")
    Orderdetail findById(int id);
}

測試

/**
 * @Auther: yanqi
 * @Date:
 * @Dese:
 */
public class UserMapperTest {

    private UserMapper userMapper;
    private OrderMapper orderMapper;
    private SqlSession sqlSession ;
    private SqlSessionFactory sqlSessionFactory ;


    @Before
    public void setUp() throws Exception {
        String resource = "mybatis-config.xml";
        InputStream inputStream = Resources.getResourceAsStream(resource);
        sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        sqlSession = sqlSessionFactory.openSession();
        userMapper = sqlSession.getMapper(UserMapper.class);
        orderMapper = sqlSession.getMapper(OrderMapper.class);

    }

    /**
     * 測試一對多
     */
    @Test
    public void oneToMany(){
        List<Order> orders = this.orderMapper.oneToMany("20200921002");
        for(Order order : orders){
            System.out.println(order);
    }

多對多

實體類

/**
 * 訂單詳情
 */
@Data
public class Orderdetail {
    private Integer id;
    private Double totalPrice;
    private Integer status;

    //商品資訊
    private Item item;
}

/**
 * 商品表
 */
@Data
public class Item {
    private Integer id;
    private String itemName;
    private Float itemPrice;
    private String itemDetail;
}

Mapper接口

public interface OrderMapper {
       /**
     * 查詢訂單，查詢出下單人資訊并且查詢出訂單詳情中的商品資料。
     */
    @Select("select * from tb_order where order_number = #{orderNum}")
    @Results({
            /*映射user*/
            @Result(column = "id",
                    property ="user",
                    javaType = User.class,
                    one = @One(select = "cn.yanqi.mapper.UserMapper.findById")),
            /*映射orderdetails*/
            @Result(column = "id",
                    property = "orderdetails",
                    javaType =List.class,
                    //查詢Item商品
                    many = @Many(select = "cn.yanqi.mapper.ItemMapper.findById"))
            })
    List<Order> manyToMany(String orderNum);
    
}

public interface ItemMapper {

    @Select("select * from tb_item where id = #{id}")
    List<Item> findById(Integer id);
    
}

測試

/**
     * 測試多對多
     */
    @Test
    public void manyToMany() {
        List<Order> orders = this.orderMapper.manyToMany("20200921002");
        for (Order order : orders) {
            System.out.println(order);
        }
    }

JAVAEE架構技術之10-myBatis注解式開發

Mybatis注解開發

資料庫準備

添加依賴

核心配置檔案

jdbc.properties

單表操作

實體類

Mapper接口

測試

一對一

實體類

Mapper接口

測試

一對多

實體類

Mapper接口

測試

多對多

實體類

Mapper接口

測試

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