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Mybatis的注解开发学习笔记

作者：繁依Fanyi0 | 2024-08-03 06:56:40

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Mybatis的注解开发学习笔记

学习视频:5001 @Select注解_哔哩哔哩_bilibili~5009 案例：基于MyBatis注解的学生管理程序_哔哩哔哩_bilibili

目录

1.基于注解的单表增删改查

        1.1@Select注解

1.2Insert注解

1.3Update注解

1.4Delete注解

1.5Param注解

2.基于注解的关联查询

        2.1一对一查询

2.2一对多查询

2.3多对多查询

3.基于MyBatis注解的学生管理程序

查询id为2的学生信息 

修改学生信息

一对多查询班级为二班的学生

1.基于注解的单表增删改查

        1.1@Select注解

数据准备

product表

  1. package com.it.pojo;
  2.  
  3. public class Product    {
  4.     private int id;
  5.     private String goodsname;
  6.     private int price;
  7.     private int typeid;
  8.  
  9.     @Override
  10.     public String toString() {
  11.         return "Product{" +
  12.                 "id=" + id +
  13.                 ", goodsname='" + goodsname + '\'' +
  14.                 ", price=" + price +
  15.                 ", typeid=" + typeid +
  16.                 '}';
  17.     }
  18.  
  19.     public int getId() {
  20.         return id;
  21.     }
  22.  
  23.     public void setId(int id) {
  24.         this.id = id;
  25.     }
  26.  
  27.     public String getGoodsname() {
  28.         return goodsname;
  29.     }
  30.  
  31.     public void setGoodsname(String goodsname) {
  32.         this.goodsname = goodsname;
  33.     }
  34.  
  35.     public int getPrice() {
  36.         return price;
  37.     }
  38.  
  39.     public void setPrice(int price) {
  40.         this.price = price;
  41.     }
  42.  
  43.     public int getTypeid() {
  44.         return typeid;
  45.     }
  46.  
  47.     public void setTypeid(int typeid) {
  48.         this.typeid = typeid;
  49.     }
  50. }
  1. package com.it.dao;
  2.  
  3. import com.it.pojo.Product;
  4. import org.apache.ibatis.annotations.Select;
  5.  
  6. public interface ProductMapper {
  7.     @Select("select  * from product where id=#{id}")
  8.     public Product findProductById(int id);
  9.  
  10. }

  1. package com.it.dao;
  2.  
  3. import com.it.pojo.Product;
  4. import com.it.utils.MyBatisUtils;
  5. import junit.framework.TestCase;
  6. import org.junit.Before;
  7.  
  8. import org.apache.ibatis.session.SqlSession;
  9. import org.junit.After;
  10. import org.junit.Test;
  11.  
  12. public class ProductMapperTest extends TestCase {
  13.     private ProductMapper productMapper;
  14.     private SqlSession session;
  15.  
  16.     @Before
  17.     public void setUp()
  18.     {
  19.         session= MyBatisUtils.getSession();
  20.        productMapper=session.getMapper(ProductMapper.class);
  21.     }
  22.     @Test
  23.     public void testFindProductById() {
  24.       Product product= productMapper.findProductById(1);
  25.         System.out.println(product);
  26.  
  27.     }
  28.  
  29.     @After
  30.     public void release()
  31.     {
  32.         session.close();
  33.     }
  34.  
  35.  
  36. }

1.2Insert注解

  1.  
  2.     @Insert("insert into product(goodsname,price,typeid) values (#{goodsname},#{price},#{typeid})")
  3.     public int insertProduct(Product product);
  1.  @Test
  2.     public void testinsertProduct()
  3.     {
  4.         Product product2=new Product();
  5.         product2.setGoodsname("风扇");
  6.         product2.setPrice(200);
  7.         product2.setTypeid(2);
  8.         int  i= productMapper.insertProduct(product2);
  9.         System.out.println(i);
  10.         session.commit();
  11.  
  12.     }

1.3Update注解

  1.    @Update("update product set goodsname=#{goodsname},price=#{price} where id=#{id}")
  2.     public int updateProduct(Product product);
  1.  @Test
  2.     public void  testupdateProduct()
  3.     {
  4.         Product product2=new Product();
  5.         product2.setGoodsname("大风扇");
  6.         product2.setId(5);
  7.         product2.setPrice(300);
  8.         int i=    productMapper.updateProduct(product2);
  9.         System.out.println(i);
  10.         session.commit();
  11.  
  12.  
  13.     }

1.4Delete注解

  1.  @Delete("delete from product where id=#{id}")
  2.     public int deleteProduct(int id);
  1.   @Test
  2.     public void testdeleteProduct()
  3.     {
  4.         int i= productMapper.deleteProduct(5);
  5.         if (i>0)
  6.         {
  7.             System.out.println("删除成功");
  8.         }
  9.         session.commit();
  10.  
  11.  
  12.     }

1.5Param注解

  1. @Select("select * from product where id=#{param01} and goodsname=#{param02}")
  2.     public Product selectProductByIdAndGoodsname(@Param("param01") int id,
  3.                                             @Param("param02") String goodsname);
  1.  @Test
  2.     public void testselectProductByIdAndGoodsname()
  3.     {
  4.         Product product=productMapper.selectProductByIdAndGoodsname(1,"电视机");
  5.         System.out.println(product);
  6.  
  7.     }

2.基于注解的关联查询

        2.1一对一查询

  1. package com.it.pojo;
  2.  
  3. public class IdCard {
  4.     private int id;
  5.     private String code;
  6.  
  7.     @Override
  8.     public String toString() {
  9.         return "IdCard{" +
  10.                 "id=" + id +
  11.                 ", code='" + code + '\'' +
  12.                 '}';
  13.     }
  14.  
  15.     public int getId() {
  16.         return id;
  17.     }
  18.  
  19.     public void setId(int id) {
  20.         this.id = id;
  21.     }
  22.  
  23.     public String getCode() {
  24.         return code;
  25.     }
  26.  
  27.     public void setCode(String code) {
  28.         this.code = code;
  29.     }
  30. }
  1. package com.it.pojo;
  2.  
  3. public class Person {
  4.     private int id;
  5.     private String name;
  6.     private int age;
  7.     private String sex;
  8.     private IdCard card;
  9.  
  10.     @Override
  11.     public String toString() {
  12.         return "Person{" +
  13.                 "id=" + id +
  14.                 ", name='" + name + '\'' +
  15.                 ", age=" + age +
  16.                 ", sex='" + sex + '\'' +
  17.                 ", card=" + card +
  18.                 '}';
  19.     }
  20.  
  21.     public int getId() {
  22.         return id;
  23.     }
  24.  
  25.     public void setId(int id) {
  26.         this.id = id;
  27.     }
  28.  
  29.     public String getName() {
  30.         return name;
  31.     }
  32.  
  33.     public void setName(String name) {
  34.         this.name = name;
  35.     }
  36.  
  37.     public int getAge() {
  38.         return age;
  39.     }
  40.  
  41.     public void setAge(int age) {
  42.         this.age = age;
  43.     }
  44.  
  45.     public String getSex() {
  46.         return sex;
  47.     }
  48.  
  49.     public void setSex(String sex) {
  50.         this.sex = sex;
  51.     }
  52.  
  53.     public IdCard getCard() {
  54.         return card;
  55.     }
  56.  
  57.     public void setCard(IdCard card) {
  58.         this.card = card;
  59.     }
  60. }
  1. package com.it.dao;
  2.  
  3. import com.it.pojo.IdCard;
  4. import org.apache.ibatis.annotations.Select;
  5.  
  6. public interface IdCardMapper {
  7.  
  8.     @Select("select * from tb_idcard where id=#{id}")
  9.      IdCard selectIdCardById(int id);
  10.  
  11. }
  1.  
  2. public interface PersonMapper {
  3.  
  4.     @Select("select * from tb_person where id=#{id}")
  5.     @Results({@Result(
  6.                     column = "card_id",
  7.                     property = "card",
  8.                     one=@One(select = "com.it.dao.IdCardMapper.selectIdCardById")
  9.     )})
  10.     Person selectPersonById(int id);
  11.  
  12. }
  1. public class PersonMapperTest extends TestCase  {
  2.  
  3.     private PersonMapper personMapper;
  4.     private SqlSession session;
  5.  
  6.     @Before
  7.     public void setUp()
  8.     {
  9.         session= MyBatisUtils.getSession();
  10.         personMapper=session.getMapper(PersonMapper.class);
  11.     }
  12.     @Test
  13.     public void testSelectPersonById() {
  14.        Person person=personMapper.selectPersonById(1);
  15.  
  16.  
  17.         System.out.println(person.toString());
  18.  
  19.  
  20.     }
  21.  
  22.     @After
  23.     public void release()
  24.     {
  25.         session.close();
  26.     }
  27. }

这里将mybatis版本改为了3.5.3,不然报错 

2.2一对多查询

  1.  
  2. public class Orders {
  3.     private int id;
  4.     private String number;
  5.     private int userId;
  6.  
  7.     @Override
  8.     public String toString() {
  9.         return "Orders{" +
  10.                 "id=" + id +
  11.                 ", number='" + number + '\'' +
  12.                 ", userId=" + userId +
  13.                 '}';
  14.     }
  15.  
  16.     public int getId() {
  17.         return id;
  18.     }
  19.  
  20.     public void setId(int id) {
  21.         this.id = id;
  22.     }
  23.  
  24.     public String getNumber() {
  25.         return number;
  26.     }
  27.  
  28.     public void setNumber(String number) {
  29.         this.number = number;
  30.     }
  31.  
  32.     public int getUserId() {
  33.         return userId;
  34.     }
  35.  
  36.     public void setUserId(int userId) {
  37.         this.userId = userId;
  38.     }
  39. }
  1. public class Users {
  2.     private int id;
  3.     private String username;
  4.     private String address;
  5.     private List<Orders> ordersList;
  6.  
  7.     @Override
  8.     public String toString() {
  9.         return "Users{" +
  10.                 "id=" + id +
  11.                 ", username='" + username + '\'' +
  12.                 ", address='" + address + '\'' +
  13.                 ", ordersList=" + ordersList +
  14.                 '}';
  15.     }
  16.  
  17.     public int getId() {
  18.         return id;
  19.     }
  20.  
  21.     public void setId(int id) {
  22.         this.id = id;
  23.     }
  24.  
  25.     public String getUsername() {
  26.         return username;
  27.     }
  28.  
  29.     public void setUsername(String username) {
  30.         this.username = username;
  31.     }
  32.  
  33.     public String getAddress() {
  34.         return address;
  35.     }
  36.  
  37.     public void setAddress(String address) {
  38.         this.address = address;
  39.     }
  40. }
  1. public interface OrdersMapper {
  2.  
  3.  
  4.  
  5.     @Select("select * from tb_orders where user_id =#{id}")
  6.     @Results({
  7.             @Result(id = true,property = "id",column = "id"),
  8.             @Result(property = "number",column = "number")
  9.     })
  10.     public List<Orders> selectOrdersByUserId(int id);
  11.  
  12.  
  13. }
  1. public interface UsersMapper {
  2.  
  3.  
  4.     @Select("select * from tb_user where id=#{id}")
  5.     @Results({
  6.             @Result(id = true,property = "id",column = "id"),
  7.             @Result(property = "username",column = "username"),
  8.             @Result(property = "address",column = "address"),
  9.             @Result(
  10.                     property = "ordersList",
  11.                     column = "id",many = @Many(select = "com.it.dao.OrdersMapper.selectOrdersByUserId")
  12.             )
  14.     })
  15.     public Users selectUserById(int id);
  16.  
  17. }
  1. public class UsersMapperTest {
  2.  
  3.     @Test
  4.     public void testSelectUserById() {
  5.         SqlSession session= MyBatisUtils.getSession();
  6.         UsersMapper usersMapper = session.getMapper(UsersMapper.class);
  7.     Users users= usersMapper.selectUserById(1);
  8.         System.out.println(users);
  9.         session.close();
  10.  
  11.  
  12.     }
  13. }

2.3多对多查询

  1. public class Orders {
  2.     private int id;
  3.     private String number;
  4.     private int userId;
  5.     private List<Product2>product2List;
  6.  
  7.     @Override
  8.     public String toString() {
  9.         return "Orders{" +
  10.                 "id=" + id +
  11.                 ", number='" + number + '\'' +
  12.                 ", userId=" + userId +
  13.                 ", product2List=" + product2List +
  14.                 '}';
  15.     }
  16.  
  17.     public int getId() {
  18.         return id;
  19.     }
  20.  
  21.     public void setId(int id) {
  22.         this.id = id;
  23.     }
  24.  
  25.     public String getNumber() {
  26.         return number;
  27.     }
  28.  
  29.     public void setNumber(String number) {
  30.         this.number = number;
  31.     }
  32.  
  33.     public int getUserId() {
  34.         return userId;
  35.     }
  36.  
  37.     public void setUserId(int userId) {
  38.         this.userId = userId;
  39.     }
  40. }
  1. import java.util.List;
  2.  
  3. public class Product2 {
  4.     private int id;
  5.     private String name;
  6.     private double price;
  7.     private List<Orders>ordersList;
  8.  
  9.     @Override
  10.     public String toString() {
  11.         return "Product2{" +
  12.                 "id=" + id +
  13.                 ", name='" + name + '\'' +
  14.                 ", price=" + price +
  15.                 ", ordersList=" + ordersList +
  16.                 '}';
  17.     }
  18.  
  19.     public int getId() {
  20.         return id;
  21.     }
  22.  
  23.     public void setId(int id) {
  24.         this.id = id;
  25.     }
  26.  
  27.     public String getName() {
  28.         return name;
  29.     }
  30.  
  31.     public void setName(String name) {
  32.         this.name = name;
  33.     }
  34.  
  35.     public double getPrice() {
  36.         return price;
  37.     }
  38.  
  39.     public void setPrice(double price) {
  40.         this.price = price;
  41.     }
  42.  
  43.     public List<Orders> getOrdersList() {
  44.         return ordersList;
  45.     }
  46.  
  47.     public void setOrdersList(List<Orders> ordersList) {
  48.         this.ordersList = ordersList;
  49.     }
  50. }
  1. public interface Product2Mapper {
  2.  
  3.  
  4.     @Select("select * from tb_product where id in"+"(select product_id from tb_ordersitem where orders_id=#{orderId})")
  5.     public List<Product2> selectProduct2sByOrdersId(int orderId);
  6.  
  7. }
  1.     @Select("select  * from tb_orders where id=#{id}")
  2.     @Results(
  3.             {
  4.              @Result(id = true,column = "id",property = "id"),
  5.              @Result(column = "number",property = "number"),
  6.              @Result(
  7.                      property = "product2List",
  8.                      column = "id",
  9.                      many = @Many(select = "com.it.dao.Product2Mapper.selectProduct2sByOrdersId")
  10.              )
  11.             }
  12.     )
  13.     public Orders selectOrdersById(int id);
  1. public class OrdersMapperTest extends TestCase {
  2.  
  3.     public void testSelectOrdersById() {
  4.         SqlSession session= MyBatisUtils.getSession();
  5.         OrdersMapper ordersMapper = session.getMapper(OrdersMapper.class);
  6.  
  7.         Orders orders = ordersMapper.selectOrdersById(1);
  8.  
  9.         System.out.println(orders);
  10.         session.close();
  11.  
  12.     }
  13. }

3.基于MyBatis注解的学生管理程序

数据准备

  1. CREATE TABLE student(
  2. 	id INT PRIMARY KEY AUTO_INCREMENT,
  3. 	NAME VARCHAR(20),
  4. 	age INT,
  5. 	cid INT
  6. );
  7. INSERT INTO student VALUES(1,'张三',18,1);
  8. INSERT INTO student VALUES(2,'李四',18,2);
  9. INSERT INTO student VALUES(3,'王五',19,2);
  10. INSERT INTO student VALUES(4,'赵六',20,1);
  11.  
  12. CREATE TABLE class(
  13. 	id INT PRIMARY KEY AUTO_INCREMENT,
  14. 	classname VARCHAR(20)
  15. );
  16. INSERT INTO class VALUES(1,'一班');
  17. INSERT INTO class VALUES(2,'二班');
  18.  
  19.  
  20.  
  1.  
  2. public class Student {
  3.     private int id;
  4.     private  String name;
  5.     private  int age;
  6.     private  int cid;
  7.  
  8.     @Override
  9.     public String toString() {
  10.         return "Student{" +
  11.                 "id=" + id +
  12.                 ", name='" + name + '\'' +
  13.                 ", age=" + age +
  14.                 ", cid=" + cid +
  15.                 '}';
  16.     }
  17.  
  18.     public int getId() {
  19.         return id;
  20.     }
  21.  
  22.     public void setId(int id) {
  23.         this.id = id;
  24.     }
  25.  
  26.     public String getName() {
  27.         return name;
  28.     }
  29.  
  30.     public void setName(String name) {
  31.         this.name = name;
  32.     }
  33.  
  34.     public int getAge() {
  35.         return age;
  36.     }
  37.  
  38.     public void setAge(int age) {
  39.         this.age = age;
  40.     }
  41.  
  42.     public int getCid() {
  43.         return cid;
  44.     }
  45.  
  46.     public void setCid(int cid) {
  47.         this.cid = cid;
  48.     }
  49. }
  1. public class Iclass {
  2.     private int id;
  3.     private String classname;
  4.     //一对多映射
  5.     private List<Student>studentList;
  6.  
  7.     @Override
  8.     public String toString() {
  9.         return "Iclass{" +
  10.                 "id=" + id +
  11.                 ", classname='" + classname + '\'' +
  12.                 ", studentList=" + studentList +
  13.                 '}';
  14.     }
  15.  
  16.     public String getClassname() {
  17.         return classname;
  18.     }
  19.  
  20.     public void setClassname(String classname) {
  21.         this.classname = classname;
  22.     }
  23.  
  24.     public int getId() {
  25.         return id;
  26.     }
  27.  
  28.     public void setId(int id) {
  29.         this.id = id;
  30.     }
  31.  
  32.     public List<Student> getStudentList() {
  33.         return studentList;
  34.     }
  35.  
  36.     public void setStudentList(List<Student> studentList) {
  37.         this.studentList = studentList;
  38.     }
  39. }

查询id为2的学生信息 

  1. public interface StudentMapper {
  2.     @Select("select * from student where id=#{id}")
  3.     public Student selectStudentById(int id);
  4.  
  5.  
  6. }
  1. public class StudentMapperTest extends TestCase {
  2.  
  3.     public void testSelectStudentById() {
  4.         SqlSession session= MyBatisUtils.getSession();
  5.  
  6.         StudentMapper studentMapper= session.getMapper(StudentMapper.class);
  7.  
  8.         Student student= studentMapper.selectStudentById(2);
  9.         System.out.println(student);
  10.         session.close();
  11.  
  12.  
  13.     }
  14. }

修改学生信息

  1.     @Update("update student set name=#{name},age=#{age} where id=#{id}")
  2.     public int updateStudent(Student student);
  1.     public void testupdateStudentByName() {
  2.  
  3.         SqlSession session= MyBatisUtils.getSession();
  4.         StudentMapper studentMapper= session.getMapper(StudentMapper.class);
  5.         Student student= new Student();
  6.         student.setName("小吴");
  7.         student.setAge(20);
  8.         student.setId(4);
  9.         int i= studentMapper.updateStudent(student);
  10.         if(i>0){
  11.             System.out.println("修改成功");
  12.         }
  13.         session.commit();
  14.         session.close();
  15.  
  16.  
  17.     }

一对多查询班级为二班的学生

  1.    @Select("select * from student where cid=#{cid}")
  2.     @Results({
  3.             @Result(id =true,column = "id",property = "id"),
  4.             @Result(column = "name",property = "name"),
  5.             @Result(column = "age",property = "age")
  6.     })
  7.     public List<Student>selectStudentsByCid(int cid);
  1.     @Select("select  * from class where id=#{id}")
  2.     @Results({
  3.             @Result(id = true,column = "id",property = "id"),
  4.             @Result(property = "classname",column = "classname"),
  5.             @Result(property = "studentList",
  6.                     column = "id",
  7.                     many =@Many(select = "com.it.dao.StudentMapper.selectStudentsByCid")
  8.             )
  9.     })
  10.     public Iclass selectClassById(int id);
  1.  
  2. public class ClassMapperTest extends TestCase {
  3.  
  4.     public void testSelectClassById() {
  5.         SqlSession session= MyBatisUtils.getSession();
  6.         ClassMapper classMapper = session.getMapper(ClassMapper.class);
  7.         Iclass iclass =classMapper.selectClassById(2);
  8.         System.out.println(iclass);
  9.  
  10.         session.close();
  11.     }
  12. }

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