mybatis高级查询和注解开发

mybatis高级查询和注解开发

一.mybatis高级查询

1.环境准境

1.1sql:

CREATE TABLE `tb_item`(
	`id` int(11) not null AUTO_INCREMENT,
	`item_name` varchar(32) NOT NULL COMMENT '商品名称',
	`item_price` float(6,1) NOT NULL COMMENT '商品价格',
	`item_detail` text COMMENT '商品描述',
 PRIMARY KEY (`id`)
)ENGINE=INNODB DEFAULT CHARSET=utf8;

INSERT INTO `tb_item` VALUES('1','iPhone 6','5288.0','苹果公司新发布的手机产品。');
INSERT INTO `tb_item` VALUES('2','iPhone 6 Plus','6288.0','苹果公司发布的大屏手机。');

CREATE TABLE `tb_user`(
	`id` bigint(20) NOT NULL AUTO_INCREMENT,
	`user_name` varchar(100) DEFAULT NULL COMMENT '用户名',
	`password` varchar(100) DEFAULT NULL COMMENT '密码',
	 `name` varchar(100) DEFAULT NULL COMMENT '姓名',
  `age` int(10) DEFAULT NULL COMMENT '年龄',
  `sex` tinyint(1) DEFAULT NULL COMMENT '性别，1男性，2女性',
	PRIMARY KEY (`id`)
)ENGINE=INNODB DEFAULT CHARSET=utf8;

INSERT INTO `tb_user`VALUES('1','zhangsan','123456','张三','30','1');
INSERT INTO `tb_user`VALUES('2','lishi','123456','李四','21','0');
INSERT INTO `tb_user`VALUES('3','wangwu','123456','王五','22','1');
INSERT INTO `tb_user`VALUES('4','zhangwei','123456','张伟','20','1');
INSERT INTO `tb_user`VALUES ('5', 'lina', '123456', '李娜','28', '0');
INSERT INTO `tb_user`VALUES ('6', '蔡徐坤', '123456', '小菜','18', '1');

CREATE TABLE `tb_order`(
	`id` int(11) NOT NULL AUTO_INCREMENT,
	`user_id` bigint(20) NOT NULL,
	`order_number` varchar(20) NOT NULL COMMENT '订单号',
	PRIMARY KEY (`id`),
	KEY `FK_orders_1` (`user_id`),
	CONSTRAINT `FK_orders_1` FOREIGN KEY (`user_id`) REFERENCES `tb_user` (`id`) ON DELETE NO	ACTION ON UPDATE NO ACTION
)ENGINE=INNODB CHARSET=utf8;

INSERT INTO `tb_order` VALUES('1','1','20140921001');
INSERT INTO `tb_order` VALUES('2','2','20140921002');
INSERT INTO `tb_order` VALUES('3','1','20140921003');

CREATE TABLE `tb_orderdetail`(
	`id` int(11) NOT NULL AUTO_INCREMENT,
	`order_id` int(32) DEFAULT NULL COMMENT '订单号',
	`item_id` int(32) DEFAULT NULL COMMENT '商品id',
	`total_price` double(20,0) DEFAULT NULL COMMENT '商品总价',
	`status` int(11) DEFAULT NULL COMMENT '状态',
	PRIMARY KEY (`id`),
	KEY `FK_orderdetail_1` (`order_id`),
	KEY `FK_orderdetail_2` (`item_id`),
	CONSTRAINT `FK_orderdetail_1` FOREIGN KEY (`order_id`) REFERENCES `tb_order` (`id`),
	CONSTRAINT `FK_orderdetail_2` FOREIGN KEY (`item_id`) REFERENCES `tb_order` (`id`)
)ENGINE=INNODB CHARSET=utf8;

INSERT INTO `tb_orderdetail` VALUES('1','1','1','5288','1');
INSERT INTO `tb_orderdetail` VALUES('2','1','2','6288','1');
INSERT INTO `tb_orderdetail` VALUES('3','2','2','6288','1');
INSERT INTO `tb_orderdetail` VALUES('4','3','1','5288','1');

1.2pojo:

//Item
package com.itheima.pojo;

public class Item {
    private Integer id;
    private String itemName;
    private Float itemPrice;
    private String itemDetail;

    public Item() {
    }

    public Item(Integer id, String itemName, Float itemPrice, String itemDetail) {
        this.id = id;
        this.itemName = itemName;
        this.itemPrice = itemPrice;
        this.itemDetail = itemDetail;
    }

    public Integer getId() {
        return id;
    }

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

    public String getItemName() {
        return itemName;
    }

    public void setItemName(String itemName) {
        this.itemName = itemName;
    }

    public Float getItemPrice() {
        return itemPrice;
    }

    public void setItemPrice(Float itemPrice) {
        this.itemPrice = itemPrice;
    }

    public String getItemDetail() {
        return itemDetail;
    }

    public void setItemDetail(String itemDetail) {
        this.itemDetail = itemDetail;
    }

    @Override
    public String toString() {
        return "Item{" +
                "id=" + id +
                ", itemName='" + itemName + '\'' +
                ", itemPrice=" + itemPrice +
                ", itemDetail='" + itemDetail + '\'' +
                '}';
    }
}

//order
package com.itheima.pojo;

public class Order {
    private Integer id;
    private String orderNumber;

    public Order() {
    }

    public Order(Integer id, String orderNumber) {
        this.id = id;
        this.orderNumber = orderNumber;
    }

    public Integer getId() {
        return id;
    }

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

    public String getOrderNumber() {
        return orderNumber;
    }

    public void setOrderNumber(String orderNumber) {
        this.orderNumber = orderNumber;
    }

    @Override
    public String toString() {
        return "Order{" +
                "id=" + id +
                ", orderNumber='" + orderNumber + '\'' +
                '}';
    }
}

//orderDetail
package com.itheima.pojo;

public class Orderdetail {
    private Integer id;
    private Double totalPrice;
    private Integer status;

    public Orderdetail() {
    }

    public Orderdetail(Integer id, Double totalPrice, Integer status) {
        this.id = id;
        this.totalPrice = totalPrice;
        this.status = status;
    }

    public Integer getId() {
        return id;
    }

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

    public Double getTotalPrice() {
        return totalPrice;
    }

    public void setTotalPrice(Double totalPrice) {
        this.totalPrice = totalPrice;
    }

    public Integer getStatus() {
        return status;
    }

    public void setStatus(Integer status) {
        this.status = status;
    }

    @Override
    public String toString() {
        return "Orderdetail{" +
                "id=" + id +
                ", totalPrice=" + totalPrice +
                ", status=" + status +
                '}';
    }
}

//user
package com.itheima.pojo;

import java.io.Serializable;

public class User {
    private Long id;
    private String userName;
    private String password;
    private String name;
    private Integer age;
    private Integer sex;

    public User() {
    }

    public User(Long id, String userName, String password, String name, Integer age, Integer sex) {
        this.id = id;
        this.userName = userName;
        this.password = password;
        this.name = name;
        this.age = age;
        this.sex = sex;
    }

    public Long getId() {
        return id;
    }

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

    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 getName() {
        return name;
    }

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

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }

    public Integer getSex() {
        return sex;
    }

    public void setSex(Integer sex) {
        this.sex = sex;
    }

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

1.3mybatis-config.xml

DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">

<configuration>
    
    <properties resource="jdbc.properties">properties>
    
    <settings>
        <setting name="mapUnderscoreToCamelCase" value="true"/>
    settings>
    
    <typeAliases>
        
        <package name="com.itheima.pojo"/>
        
    typeAliases>
    
    <environments default="dev">
        
        <environment id="dev">
            
            <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>
        
        <environment id="test">
            <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://localhost:3306/hsp_db02?useUnicode=true&characterEncoding=utf-8&useSSL=false"/>
                <property name="username" value="root"/>
                <property name="password" value="123456"/>
            dataSource>
        environment>
    environments>
    
    <mappers>

        
        
        
        
        <package name="com.itheima.dao"/>
    mappers>
configuration>

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/mybatis_db?useUnicode=true&characterEncoding=utf-8&useSSL=false
jdbc.username=root
jdbc.password=123456

1.4MybatisUtils工具类

package com.itheima.utils;

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

import java.io.IOException;
import java.io.InputStream;

//工具类：私有化构造器+静态方 法
public class MybatisUtil {
    //私有化构造方法
    private MybatisUtil(){}

    //SqlSessionFactory工厂类对象
    private static SqlSessionFactory sqlSessionFactory=null;
    //随着类的加载，仅执行一次
    static {
        try {
            //读取配置文件
            InputStream is = Resources.getResourceAsStream("mybatis-config.xml");
            //创建SqlSessionFactory工厂类
            sqlSessionFactory = new SqlSessionFactoryBuilder().build(is);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    //静态方法返回SqlSession对象
    public static SqlSession openSession(){
        //使用SqlSessionFactory工厂类，创建SqlSession对象
        return sqlSessionFactory.openSession(); //默认：手动事务
    }

    public static SqlSession openSession(boolean flag){
        //使用SqlSessionFactory工厂类，创建SqlSession对象
        return sqlSessionFactory.openSession(flag);//根据参数指定事务
    }

    //静态方法关闭sqlSession
    public static void closeSqlSession(SqlSession sqlSession){
        if(sqlSession!=null){
            sqlSession.close();
        }
    }
}

1.5userMapper接口

public interface UserMapper {
    /**
     * 根据用户ID查询用户信息
     * @param id 用户ID
     * @return  返回对象
     */
    public User findUserById(Integer id);
}

1.6userMapper.xml

DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<mapper namespace="com.itheima.dao.UserMapper">
    <select id="findUserById" resultType="com.itheima.pojo.User">
        select id,user_name as userName,password,name,age,sex from tb_user
        where id=#{id}
    select>
mapper>

1.7测试代码

package com.itheima;

import com.itheima.dao.UserMapper;
import com.itheima.pojo.User;
import com.itheima.utils.MybatisUtil;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;

public class UserMapperTest {
    @Test
    public void testFindUserById(){
        //使用SqlSessionFactory工厂类，创建SqlSession
        SqlSession sqlSession = MybatisUtil.openSession();

        //利用sqlSession，创建一个代理对象
        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);

        User user = userMapper.findUserById(1);
        System.out.println(user);
        //释放资源
        MybatisUtil.closeSqlSession(sqlSession);

    }
}

2.一对一查询

mybatis多表查询的套路：

1.基于需求编写SQ语句

2.基于SQL语句的查询结果，分析类与类之间关联（建立实体类和实体类的关联）

1对1查询结果：在Order类添加新属性:User 对象

3.在映射文年中，基于SQL查询结果（配置关联）

2.1SQL

select tb_order.id as order_id,
 tb_order.order_number,
 tb_user.id as user_id,
 tb_user.user_name,
 tb_user.password,
 tb_user.name,
 tb_user.sex,
 tb_user.age
from tb_order inner join tb_user
on tb_user.id=tb_order.user_id
where tb_order.order_number='20140921003'

2.2orderMapper.xml

DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<mapper namespace="com.itheima.dao.OrderMapper">
    
    <resultMap id="orderMap" type="com.itheima.pojo.Order" autoMapping="true">
        
        <id column="order_id" property="id">id>
        <result column="order_number" property="orderNumber">result>
        
        <association property="orderUser" javaType="com.itheima.pojo.User">
            <id column="user_id" property="id">id>
            <result column="user_name" property="userName">result>
        association>


    resultMap>
    
    <select id="findOrderByNumber" resultMap="orderMap">
        select tb_order.id as order_id,
               tb_order.order_number,
               tb_user.id as user_id,
               tb_user.user_name,
               tb_user.password,
               tb_user.name,
               tb_user.sex,
               tb_user.age
        from tb_order inner join tb_user
                                 on tb_user.id=tb_order.user_id
        where tb_order.order_number=#{orderNumber}
    select>
mapper>

2.3orderMapper接口

package com.itheima.dao;

import com.itheima.pojo.Order;

public interface OrderMapper {
    /**
     * 根成订单号查询订单信息
     * @param orderNumber
     * @return
     */
    public Order findOrderByNumber(String orderNumber);
}

2.4pojo

order

package com.itheima.pojo;

public class Order {
    private Integer id; //订单ID
    private String orderNumber;//订单编号

    public User getOrderUser() {
        return orderUser;
    }

    public void setOrderUser(User orderUser) {
        this.orderUser = orderUser;
    }

    //下单人
    private User orderUser; //用户对象

    public Integer getId() {
        return id;
    }

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

    public String getOrderNumber() {
        return orderNumber;
    }

    public void setOrderNumber(String orderNumber) {
        this.orderNumber = orderNumber;
    }

    @Override
    public String toString() {
        return "Order{" +
                "id=" + id +
                ", orderNumber='" + orderNumber + '\'' +
                '}';
    }


}

user

package com.itheima.pojo;

import java.io.Serializable;
import java.util.List;

public class User {
    private Long id;
    private String userName;
    private String password;
    private String name;
    private Integer age;
    private Integer sex;


    public Long getId() {
        return id;
    }

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

    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 getName() {
        return name;
    }

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

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }

    public Integer getSex() {
        return sex;
    }

    public void setSex(Integer sex) {
        this.sex = sex;
    }

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

2.5测试代码

package com.itheima;

import com.itheima.dao.OrderMapper;
import com.itheima.dao.UserMapper;
import com.itheima.pojo.Order;
import com.itheima.pojo.User;
import com.itheima.utils.MybatisUtil;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;

public class OrderMapperTest {
    @Test
    public void testFindOrderByNumber(){
        //使用SqlSessionFactory工厂类，创建SqlSession
        SqlSession sqlSession = MybatisUtil.openSession();

        //利用sqlSession，创建一个代理对象
        OrderMapper orderMapper = sqlSession.getMapper(OrderMapper.class);

        Order order = orderMapper.findOrderByNumber("20140921003");
        System.out.println("订单信息"+order);
        User user=order.getOrderUser();
        System.out.println("订单人信息:"+user);
        //释放资源
        MybatisUtil.closeSqlSession(sqlSession);

    }
}

2.6运行结果

2024-01-19 14:30:50.512 [DEBUG] org.apache.ibatis.transaction.jdbc.JdbcTransaction [main] : Opening JDBC Connection
2024-01-19 14:30:51.219 [DEBUG] org.apache.ibatis.datasource.pooled.PooledDataSource [main] : Created connection 1267149311.
2024-01-19 14:30:51.220 [DEBUG] org.apache.ibatis.transaction.jdbc.JdbcTransaction [main] : Setting autocommit to false on JDBC Connection [com.mysql.jdbc.JDBC4Connection@4b8729ff]
2024-01-19 14:30:51.226 [DEBUG] com.itheima.dao.OrderMapper.findOrderByNumber [main] : > Preparing: select tb_order.id as order_id, tb_order.order_number, tb_user.id as user_id, tb_user.user_name, tb_user.password, tb_user.name, tb_user.sex, tb_user.age from tb_order inner join tb_user on tb_user.id=tb_order.user_id where tb_order.order_number=?
2024-01-19 14:30:51.312 [DEBUG] com.itheima.dao.OrderMapper.findOrderByNumber [main] : > Parameters: 20140921003(String)
2024-01-19 14:30:51.350 [TRACE] com.itheima.dao.OrderMapper.findOrderByNumber [main] : < Columns: order_id, order_number, user_id, user_name, password, name, sex, age
2024-01-19 14:30:51.351 [TRACE] com.itheima.dao.OrderMapper.findOrderByNumber [main] : < Row: 3, 20140921003, 1, zhangsan, 123456, 张三, 1, 30
2024-01-19 14:30:51.355 [DEBUG] com.itheima.dao.OrderMapper.findOrderByNumber [main] : <== Total: 1
订单信息Order{id=3, orderNumber=‘20140921003’}
订单人信息:User{id=1, userName=‘zhangsan’, password=‘null’, name=‘null’, age=null, sex=null}
2024-01-19 14:30:51.380 [DEBUG] org.apache.ibatis.transaction.jdbc.JdbcTransaction [main] : Resetting autocommit to true on JDBC Connection [com.mysql.jdbc.JDBC4Connection@4b8729ff]
2024-01-19 14:30:51.381 [DEBUG] org.apache.ibatis.transaction.jdbc.JdbcTransaction [main] : Closing JDBC Connection [com.mysql.jdbc.JDBC4Connection@4b8729ff]
2024-01-19 14:30:51.382 [DEBUG] org.apache.ibatis.datasource.pooled.PooledDataSource [main] : Returned connection 1267149311 to pool.

Process finished with exit code 0

3.一对多查询

1对多查询结果：在User类中添加新属性：List 集合

3.1SQL

select 
 tb_user.id as user_id,
 tb_user.user_name,
 tb_user.password,
 tb_user.name,
 tb_user.sex,
 tb_user.age,
 tb_order.id as order_id,
 tb_order.order_number
from tb_order inner join tb_user
on tb_user.id=tb_order.user_id
where tb_user.id=1

3.2userMapperXml

DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<mapper namespace="com.itheima.dao.UserMapper">
    
    <resultMap id="userMap" type="com.itheima.pojo.User" autoMapping="true">
        
        <id column="user_id" property="id">id>
        <result column="user_name" property="userName">result>

        
        <collection property="orders"
                    javaType="java.util.List"
                    ofType="com.itheima.pojo.Order">
            <id column="order_id" property="id">id>
            <result column="order_number" property="orderNumber">result>
        collection>
        

    resultMap>
    
    <select id="findUserById" resultMap="userMap">
        select
            tb_user.id as user_id,
            tb_user.user_name,
            tb_user.password,
            tb_user.name,
            tb_user.sex,
            tb_user.age,
            tb_order.id as order_id,
            tb_order.order_number
        from tb_order inner join tb_user
                                 on tb_user.id=tb_order.user_id
        where tb_user.id=#{id}
    select>
mapper>

3.3userMapper接口

package com.itheima.dao;

import com.itheima.pojo.User;

public interface UserMapper {
    /**
     * 根据用户ID查询用户信息及下单信息
     * @param id 用户ID
     * @return  返回对象
     */
    public User findUserById(Integer id);
}

3.4pojo

user

package com.itheima.pojo;

import java.io.Serializable;
import java.util.List;

public class User {
    private Long id;
    private String userName;
    private String password;
    private String name;
    private Integer age;
    private Integer sex;

    public List<Order> getOrders() {
        return orders;
    }

    public void setOrders(List<Order> orders) {
        this.orders = orders;
    }

    //一个用户多个订单(1:多)
    private List<Order> orders;


    public Long getId() {
        return id;
    }

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

    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 getName() {
        return name;
    }

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

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }

    public Integer getSex() {
        return sex;
    }

    public void setSex(Integer sex) {
        this.sex = sex;
    }

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

order

package com.itheima.pojo;

public class Order {
    private Integer id; //订单ID
    private String orderNumber;//订单编号

    public User getOrderUser() {
        return orderUser;
    }

    public void setOrderUser(User orderUser) {
        this.orderUser = orderUser;
    }

    //下单人
    private User orderUser; //用户对象

    public Integer getId() {
        return id;
    }

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

    public String getOrderNumber() {
        return orderNumber;
    }

    public void setOrderNumber(String orderNumber) {
        this.orderNumber = orderNumber;
    }

    @Override
    public String toString() {
        return "Order{" +
                "id=" + id +
                ", orderNumber='" + orderNumber + '\'' +
                '}';
    }


}

3.5测试代 码

package com.itheima;

import com.itheima.dao.UserMapper;
import com.itheima.pojo.Order;
import com.itheima.pojo.User;
import com.itheima.utils.MybatisUtil;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;

import java.util.List;

public class UserMapperTest {
    @Test
    public void testFindUserById(){
        //使用SqlSessionFactory工厂类，创建SqlSession
        SqlSession sqlSession = MybatisUtil.openSession();

        //利用sqlSession，创建一个代理对象
        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);

        User user = userMapper.findUserById(1);
        MybatisUtil.closeSqlSession(sqlSession);

        System.out.println("用户信息："+user);
        List<Order> orderList=user.getOrders();
        for(Order order:orderList){
            System.out.println(order);
        }
        //释放资源


    }
}

3.6运行结果

2024-01-19 16:21:25.700 [DEBUG] org.apache.ibatis.transaction.jdbc.JdbcTransaction [main] : Resetting autocommit to true on JDBC Connection [com.mysql.jdbc.JDBC4Connection@4b8729ff]
2024-01-19 16:21:25.703 [DEBUG] org.apache.ibatis.transaction.jdbc.JdbcTransaction [main] : Closing JDBC Connection [com.mysql.jdbc.JDBC4Connection@4b8729ff]
2024-01-19 16:21:25.703 [DEBUG] org.apache.ibatis.datasource.pooled.PooledDataSource [main] : Returned connection 1267149311 to pool.
用户信息：User{id=1, userName=‘zhangsan’, password=‘123456’, name=‘张三’, age=30, sex=1}
Order{id=1, orderNumber=‘20140921001’}
Order{id=3, orderNumber=‘20140921003’}

Process finished with exit code 0

二.mybatis注解开发

1.CRUD详解

@Insert:保存

​ Value: sql语句(和xml的配置方式一模一样)

@Update:更新

​ Value: sql语句

@Delete:语句

​ Value: sql语句

@ Select 语句

​ Value: sql语句

@Options:可选配置（获取主键）

​ userGenerateKeys:开关值为true表示可以获取主键 相当于select last_insert_id()

​ keyProperty:对象属性

​ keyColumn:列名

步骤：
​	1.将mybatis全局配置文件mybatis-config.xml中的mapper的路径改为包扫描或者class路径
​	2.编写接口和注解
​	3.测试

2.insert

2.1userMapper接口

package com.itheima.dao;

import com.itheima.pojo.User;
import org.apache.ibatis.annotations.Insert;

public interface UserMapper {
    /**
     * 添加用户
     * @param user 用户对象
     * @return 有影响的行数
     */
    @Insert("INSERT INTO tb_user(user_name,password,name,age,sex) " +
            "VALUES(#{userName},#{password},#{name},#{age},#{sex})")
    public int addUser(User user);

}

2.2测试代码

package com.itheima;

import com.itheima.dao.UserMapper;
import com.itheima.pojo.Order;
import com.itheima.pojo.User;
import com.itheima.utils.MybatisUtil;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;

import java.util.List;

public class UserMapperTest {
    @Test
    public void testAddUser(){
        //使用SqlSessionFactory工厂类，创建SqlSession
        SqlSession sqlSession = MybatisUtil.openSession();

        //利用sqlSession，创建一个代理对象
        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);

        User user = new User();
        user.setUserName("测试注解");
        user.setPassword("123456");
        user.setName("注解");
        user.setSex(1);
        user.setAge(14);
        int count=userMapper.addUser(user);
        if(count>0){
            System.out.println("添加成功");
        }
        //释放资源
        MybatisUtil.closeSqlSession(sqlSession);

    }
}

2.3测试结果

2024-01-19 16:53:34.672 [DEBUG]  org.apache.ibatis.io.ResolverUtil [main] : Checking to see if class com.itheima.dao.UserMapper matches criteria [is assignable to Object]
2024-01-19 16:53:34.848 [DEBUG]  org.apache.ibatis.transaction.jdbc.JdbcTransaction [main] : Opening JDBC Connection
2024-01-19 16:53:35.435 [DEBUG]  org.apache.ibatis.datasource.pooled.PooledDataSource [main] : Created connection 771418758.
2024-01-19 16:53:35.437 [DEBUG]  org.apache.ibatis.transaction.jdbc.JdbcTransaction [main] : Setting autocommit to false on JDBC Connection [com.mysql.jdbc.JDBC4Connection@2dfaea86]
2024-01-19 16:53:35.444 [DEBUG]  com.itheima.dao.UserMapper.addUser [main] : ==>  Preparing: INSERT INTO tb_user(user_name,password,name,age,sex) VALUES(?,?,?,?,?) 
2024-01-19 16:53:35.584 [DEBUG]  com.itheima.dao.UserMapper.addUser [main] : ==> Parameters: 测试注解(String), 123456(String), 注解(String), 14(Integer), 1(Integer)
2024-01-19 16:53:35.604 [DEBUG]  com.itheima.dao.UserMapper.addUser [main] : <==    Updates: 1
添加成功
2024-01-19 16:53:35.605 [DEBUG]  org.apache.ibatis.transaction.jdbc.JdbcTransaction [main] : Rolling back JDBC Connection [com.mysql.jdbc.JDBC4Connection@2dfaea86]
2024-01-19 16:53:35.610 [DEBUG]  org.apache.ibatis.transaction.jdbc.JdbcTransaction [main] : Resetting autocommit to true on JDBC Connection [com.mysql.jdbc.JDBC4Connection@2dfaea86]
2024-01-19 16:53:35.612 [DEBUG]  org.apache.ibatis.transaction.jdbc.JdbcTransaction [main] : Closing JDBC Connection [com.mysql.jdbc.JDBC4Connection@2dfaea86]
2024-01-19 16:53:35.612 [DEBUG]  org.apache.ibatis.datasource.pooled.PooledDataSource [main] : Returned connection 771418758 to pool.

Process finished with exit code 0

3.select

3.1 userMapper接口

package com.itheima.dao;

import com.itheima.pojo.User;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Param;
import org.apache.ibatis.annotations.Select;
import org.apache.ibatis.annotations.Update;

import java.util.List;

public interface UserMapper {

    @Update("update tb_user set password=#{password} where user_name=#{username}")
   public int updateUser(@Param("username") String name,
                          @Param("password") String password);

    @Select("SELECT user_name,password,name,age,sex from tb_user")
    public List<User> findAll();
}

3.2测试代码

@Test
public void testUpdateUser(){
    //使用SqlSessionFactory工厂类，创建SqlSession
    SqlSession sqlSession = MybatisUtil.openSession(true);

    //利用sqlSession，创建一个代理对象
    UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
    int Count=userMapper.updateUser("蔡徐坤","12345678");
    if(Count>0){
        System.out.println("更新成功");
    }
    //释放资源
    MybatisUtil.closeSqlSession(sqlSession);

}

3.3运行结果

2024-01-19 17:11:18.153 [DEBUG]  org.apache.ibatis.transaction.jdbc.JdbcTransaction [main] : Opening JDBC Connection
2024-01-19 17:11:18.832 [DEBUG]  org.apache.ibatis.datasource.pooled.PooledDataSource [main] : Created connection 944140566.
2024-01-19 17:11:18.840 [DEBUG]  com.itheima.dao.UserMapper.updateUser [main] : ==>  Preparing: update tb_user set password=? where user_name=? 
2024-01-19 17:11:18.934 [DEBUG]  com.itheima.dao.UserMapper.updateUser [main] : ==> Parameters: 12345678(String), 蔡徐坤(String)
2024-01-19 17:11:18.943 [DEBUG]  com.itheima.dao.UserMapper.updateUser [main] : <==    Updates: 1
更新成功
2024-01-19 17:11:18.944 [DEBUG]  org.apache.ibatis.transaction.jdbc.JdbcTransaction [main] : Closing JDBC Connection [com.mysql.jdbc.JDBC4Connection@38467116]
2024-01-19 17:11:18.945 [DEBUG]  org.apache.ibatis.datasource.pooled.PooledDataSource [main] : Returned connection 944140566 to pool.

4.主键回填

主键回填技术：在向数据表中插入一行数据时，会返回所插入行的主键列表数据，主键列表数据会回填到实体类的属性中（和主键关联的属性）

4.1userMapper接口

package com.itheima.dao;

import com.itheima.pojo.User;
import org.apache.ibatis.annotations.*;

import java.util.List;

public interface UserMapper {
    /**
     * 添加用户
     * @param user 用户对象
     * @return 有影响的行数
     */

    @Insert("INSERT INTO tb_user(user_name,password,name,age,sex) " +
            "VALUES(#{userName},#{password},#{name},#{age},#{sex})")
    //useGeneratedKeys 开启主键回填，keyColumn="表中的主键字段名" keyProperty="实体类中的属性名"
    @Options(useGeneratedKeys = true,keyColumn ="id",keyProperty = "id")
    public int addUserGetPk(User user);
}

4.2测试代码

    @Test
    public void testAaddUser(){
        //使用SqlSessionFactory工厂类，创建SqlSession
        SqlSession sqlSession = MybatisUtil.openSession(true);

        //利用sqlSession，创建一个代理对象
        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);

        User user = new User();
        user.setUserName("测试注解");
        user.setPassword("123456");
        user.setName("注解");
        user.setSex(1);
        user.setAge(14);
        int count=userMapper.addUserGetPk(user);
        if(count>0){
            System.out.println("添加成功");
        }
        //释放资源
        MybatisUtil.closeSqlSession(sqlSession);

    }

4.3运行结果

2024-01-19 17:21:56.939 [DEBUG]  org.apache.ibatis.transaction.jdbc.JdbcTransaction [main] : Opening JDBC Connection
2024-01-19 17:21:57.846 [DEBUG]  org.apache.ibatis.datasource.pooled.PooledDataSource [main] : Created connection 859654796.
2024-01-19 17:21:57.852 [DEBUG]  com.itheima.dao.UserMapper.addUserGetPk [main] : ==>  Preparing: INSERT INTO tb_user(user_name,password,name,age,sex) VALUES(?,?,?,?,?) 
2024-01-19 17:21:57.953 [DEBUG]  com.itheima.dao.UserMapper.addUserGetPk [main] : ==> Parameters: 测试注解(String), 123456(String), 注解(String), 14(Integer), 1(Integer)
2024-01-19 17:21:57.961 [DEBUG]  com.itheima.dao.UserMapper.addUserGetPk [main] : <==    Updates: 1
添加成功
2024-01-19 17:21:57.965 [DEBUG]  org.apache.ibatis.transaction.jdbc.JdbcTransaction [main] : Closing JDBC Connection [com.mysql.jdbc.JDBC4Connection@333d4a8c]
2024-01-19 17:21:57.965 [DEBUG]  org.apache.ibatis.datasource.pooled.PooledDataSource [main] : Returned connection 859654796 to pool.

5.Results结果集映射

当查询结果中的列名和 实体类的属性名不一致时：

1.在SQL语句中，添加别名（别名和实体类中的属性类一致）

2.在核心配置文件中，配置驼峰映射

3.使用resultMap标签，设置查询后结果和实体类的映射关系

5.1接口

@Select("SELECT id,user_name,password,name,age,sex from tb_user")
@Results(id = "userMap",value={
    @Result(column = "id",property = "id",id = true),
    @Result(column = "user_name",property = "userName")
})
public List<User> findAll();

5.2测试代码

@Test
public void testFindAllUser(){
    //使用SqlSessionFactory工厂类，创建SqlSession
    SqlSession sqlSession = MybatisUtil.openSession();

    //利用sqlSession，创建一个代理对象
    UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
    List<User> userList=userMapper.findAll();
    //释放资源
    MybatisUtil.closeSqlSession(sqlSession);
    for (User user:userList){
        System.out.println(user);
    }
}

5.3运行结果

2024-01-19 17:40:13.684 [DEBUG]  org.apache.ibatis.transaction.jdbc.JdbcTransaction [main] : Opening JDBC Connection
2024-01-19 17:40:14.339 [DEBUG]  org.apache.ibatis.datasource.pooled.PooledDataSource [main] : Created connection 1326393666.
2024-01-19 17:40:14.340 [DEBUG]  org.apache.ibatis.transaction.jdbc.JdbcTransaction [main] : Setting autocommit to false on JDBC Connection [com.mysql.jdbc.JDBC4Connection@4f0f2942]
2024-01-19 17:40:14.346 [DEBUG]  com.itheima.dao.UserMapper.findAll [main] : ==>  Preparing: SELECT id,user_name,password,name,age,sex from tb_user 
2024-01-19 17:40:14.566 [DEBUG]  com.itheima.dao.UserMapper.findAll [main] : ==> Parameters: 
2024-01-19 17:40:14.858 [TRACE]  com.itheima.dao.UserMapper.findAll [main] : <==    Columns: id, user_name, password, name, age, sex
2024-01-19 17:40:14.859 [TRACE]  com.itheima.dao.UserMapper.findAll [main] : <==        Row: 1, zhangsan, 123456, 张三, 30, 1
2024-01-19 17:40:14.865 [TRACE]  com.itheima.dao.UserMapper.findAll [main] : <==        Row: 2, lishi, 123456, 李四, 21, 0
2024-01-19 17:40:14.870 [TRACE]  com.itheima.dao.UserMapper.findAll [main] : <==        Row: 3, wangwu, 123456, 王五, 22, 1
2024-01-19 17:40:14.872 [TRACE]  com.itheima.dao.UserMapper.findAll [main] : <==        Row: 4, zhangwei, 123456, 张伟, 20, 1
2024-01-19 17:40:14.873 [TRACE]  com.itheima.dao.UserMapper.findAll [main] : <==        Row: 5, lina, 123456, 李娜, 28, 0
2024-01-19 17:40:14.875 [TRACE]  com.itheima.dao.UserMapper.findAll [main] : <==        Row: 6, 蔡徐坤, 12345678, 小菜, 18, 1
2024-01-19 17:40:14.910 [TRACE]  com.itheima.dao.UserMapper.findAll [main] : <==        Row: 8, 测试注解, 123456, 注解, 14, 1
2024-01-19 17:40:14.938 [DEBUG]  com.itheima.dao.UserMapper.findAll [main] : <==      Total: 7
2024-01-19 17:40:14.940 [DEBUG]  org.apache.ibatis.transaction.jdbc.JdbcTransaction [main] : Resetting autocommit to true on JDBC Connection [com.mysql.jdbc.JDBC4Connection@4f0f2942]
2024-01-19 17:40:14.942 [DEBUG]  org.apache.ibatis.transaction.jdbc.JdbcTransaction [main] : Closing JDBC Connection [com.mysql.jdbc.JDBC4Connection@4f0f2942]
2024-01-19 17:40:14.944 [DEBUG]  org.apache.ibatis.datasource.pooled.PooledDataSource [main] : Returned connection 1326393666 to pool.
User{id=1, userName='zhangsan', password='123456', name='张三', age=30, sex=1}
User{id=2, userName='lishi', password='123456', name='李四', age=21, sex=0}
User{id=3, userName='wangwu', password='123456', name='王五', age=22, sex=1}
User{id=4, userName='zhangwei', password='123456', name='张伟', age=20, sex=1}
User{id=5, userName='lina', password='123456', name='李娜', age=28, sex=0}
User{id=6, userName='蔡徐坤', password='12345678', name='小菜', age=18, sex=1}
User{id=8, userName='测试注解', password='123456', name='注解', age=14, sex=1}

6.模糊查询

6.1userMapper接口

package com.itheima.dao;

import com.itheima.pojo.User;
import org.apache.ibatis.annotations.*;

import java.util.List;

public interface UserMapper {
    /**
     * 根据给定名字，模糊查询用户数据
     * @param name 名字
     * @return 存储用户对象的集合
     */
    @Select("select id,user_name AS userName,password,name,age,sex" +
            " from tb_user" +
            " where sex=1 AND name like concat('%',#{name},'%')")
    public List<User> findUserByLike(String name);
}

6.2测试代码

@Test
public void testFindUserByLike(){
    //使用SqlSessionFactory工厂类，创建SqlSession
    SqlSession sqlSession = MybatisUtil.openSession();

    //利用sqlSession，创建一个代理对象
    UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
    List<User> userList=userMapper.findUserByLike("小");
    //释放资源
    MybatisUtil.closeSqlSession(sqlSession);
    for (User user:userList){
        System.out.println(user);
    }
}

6.3运行结果

2024-01-19 18:02:51.596 [DEBUG]  org.apache.ibatis.transaction.jdbc.JdbcTransaction [main] : Opening JDBC Connection
2024-01-19 18:02:52.614 [DEBUG]  org.apache.ibatis.datasource.pooled.PooledDataSource [main] : Created connection 308433917.
2024-01-19 18:02:52.615 [DEBUG]  org.apache.ibatis.transaction.jdbc.JdbcTransaction [main] : Setting autocommit to false on JDBC Connection [com.mysql.jdbc.JDBC4Connection@126253fd]
2024-01-19 18:02:52.622 [DEBUG]  com.itheima.dao.UserMapper.findUserByLike [main] : ==>  Preparing: select id,user_name AS userName,password,name,age,sex from tb_user where sex=1 AND name like concat('%',?,'%') 
2024-01-19 18:02:52.724 [DEBUG]  com.itheima.dao.UserMapper.findUserByLike [main] : ==> Parameters: 小(String)
2024-01-19 18:02:52.773 [TRACE]  com.itheima.dao.UserMapper.findUserByLike [main] : <==    Columns: id, userName, password, name, age, sex
2024-01-19 18:02:52.774 [TRACE]  com.itheima.dao.UserMapper.findUserByLike [main] : <==        Row: 6, 蔡徐坤, 12345678, 小菜, 18, 1
2024-01-19 18:02:52.780 [DEBUG]  com.itheima.dao.UserMapper.findUserByLike [main] : <==      Total: 1
2024-01-19 18:02:52.784 [DEBUG]  org.apache.ibatis.transaction.jdbc.JdbcTransaction [main] : Resetting autocommit to true on JDBC Connection [com.mysql.jdbc.JDBC4Connection@126253fd]
2024-01-19 18:02:52.787 [DEBUG]  org.apache.ibatis.transaction.jdbc.JdbcTransaction [main] : Closing JDBC Connection [com.mysql.jdbc.JDBC4Connection@126253fd]
2024-01-19 18:02:52.787 [DEBUG]  org.apache.ibatis.datasource.pooled.PooledDataSource [main] : Returned connection 308433917 to pool.
User{id=6, userName='蔡徐坤', password='12345678', name='小菜', age=18, sex=1}

Process finished with exit code 0

7.动态sql

方式1：

使用@SelectProvider(type=SqlProvider.class,method=“findUserByName”)method是构建SQL的方法

构建SQL的方法的参数要和接口的参数一致，并且多个参数使用@Param命名参数

方式2：

@SelectProvider+SQL类

1.定义接口

2.定义提供的类

7.1.1接口（方式1）

SqlProvider类

package com.itheima.dao;

import org.apache.ibatis.annotations.Param;

//拼接SQL语句
public class SqlProvider {
    //返回拼接后的SQL语句
    public String findUserByName(@Param("name") String name) {
        String sql="select id,user_name AS userName,password,name,age,sex from tb_user where sex=1 ";


        if(name!=null && !"".equals(name)){
            sql+=" AND name like concat('%',#{name},'%')";
        }
        return sql;
    }
}

    /**
     * 根据给定名字，模糊查询用户数据
     * @param name 名字
     * @return 存储用户对象的集合
     */
//    @Select("select id,user_name AS userName,password,name,age,sex" +
//            " from tb_user" +
//            " where sex=1 AND name like concat('%',#{name},'%')")
    @SelectProvider(type = SqlProvider.class,method = "findUserByName")
    public List<User> findUserByLike(@Param("name") String name);

7.1.2测试代码（方式1）

    @Test
    public void testFindUserByLike(){
        //使用SqlSessionFactory工厂类，创建SqlSession
        SqlSession sqlSession = MybatisUtil.openSession();

        //利用sqlSession，创建一个代理对象
        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
        List<User> userList=userMapper.findUserByLike("小");
        //释放资源
        MybatisUtil.closeSqlSession(sqlSession);
        for (User user:userList){
            System.out.println(user);
        }
    }

7.1.3运行结果（方式1）

2024-01-19 18:23:31.416 [DEBUG]  org.apache.ibatis.transaction.jdbc.JdbcTransaction [main] : Opening JDBC Connection
2024-01-19 18:23:32.363 [DEBUG]  org.apache.ibatis.datasource.pooled.PooledDataSource [main] : Created connection 1304589447.
2024-01-19 18:23:32.364 [DEBUG]  org.apache.ibatis.transaction.jdbc.JdbcTransaction [main] : Setting autocommit to false on JDBC Connection [com.mysql.jdbc.JDBC4Connection@4dc27487]
2024-01-19 18:23:32.372 [DEBUG]  com.itheima.dao.UserMapper.findUserByLike [main] : ==>  Preparing: select id,user_name AS userName,password,name,age,sex from tb_user where sex=1 AND name like concat('%',?,'%') 
2024-01-19 18:23:32.505 [DEBUG]  com.itheima.dao.UserMapper.findUserByLike [main] : ==> Parameters: 小(String)
2024-01-19 18:23:32.665 [TRACE]  com.itheima.dao.UserMapper.findUserByLike [main] : <==    Columns: id, userName, password, name, age, sex
2024-01-19 18:23:32.666 [TRACE]  com.itheima.dao.UserMapper.findUserByLike [main] : <==        Row: 6, 蔡徐坤, 12345678, 小菜, 18, 1
2024-01-19 18:23:32.669 [DEBUG]  com.itheima.dao.UserMapper.findUserByLike [main] : <==      Total: 1
2024-01-19 18:23:32.672 [DEBUG]  org.apache.ibatis.transaction.jdbc.JdbcTransaction [main] : Resetting autocommit to true on JDBC Connection [com.mysql.jdbc.JDBC4Connection@4dc27487]
2024-01-19 18:23:32.673 [DEBUG]  org.apache.ibatis.transaction.jdbc.JdbcTransaction [main] : Closing JDBC Connection [com.mysql.jdbc.JDBC4Connection@4dc27487]
2024-01-19 18:23:32.673 [DEBUG]  org.apache.ibatis.datasource.pooled.PooledDataSource [main] : Returned connection 1304589447 to pool.
User{id=6, userName='蔡徐坤', password='12345678', name='小菜', age=18, sex=1}

7.2.1接口（方式2）

sqlProvider

public class SqlProvider {

    public String findUserByName2(@Param("name") String name){
        //Mybatis提供了一个SQL类
        SQL sql=new SQL();
        //利用SQL类中提供的API方法,拼接了SQL语句
        sql=sql.SELECT(" id,user_name AS userName,password,name,age,sex").FROM("tb_user").WHERE("sex=1");
        if(name!=null){
            sql=sql.AND().WHERE("name like concat('%',#{name},'%')");
        }
        return sql.toString();
    }
}

userMapper.java
public interface UserMapper {
    @SelectProvider(type = SqlProvider.class,method = "findUserByName2")
    public List<User> findUserByLike(@Param("name") String name);
}

7.2.2测试代码

    @Test
    public void testFindUserByLike(){
        //使用SqlSessionFactory工厂类，创建SqlSession
        SqlSession sqlSession = MybatisUtil.openSession();

        //利用sqlSession，创建一个代理对象
        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
        List<User> userList=userMapper.findUserByLike("小");
        //释放资源
        MybatisUtil.closeSqlSession(sqlSession);
        for (User user:userList){
            System.out.println(user);
        }
    }

7.2.3运行结果

2024-01-22 11:08:52.107 [DEBUG]  com.itheima.dao.UserMapper.findUserByLike [main] : ==>  Preparing: SELECT id,user_name AS userName,password,name,age,sex FROM tb_user WHERE (sex=1) AND (name like concat('%',?,'%')) 
2024-01-22 11:08:52.195 [DEBUG]  com.itheima.dao.UserMapper.findUserByLike [main] : ==> Parameters: 小(String)
2024-01-22 11:08:52.229 [TRACE]  com.itheima.dao.UserMapper.findUserByLike [main] : <==    Columns: id, userName, password, name, age, sex
2024-01-22 11:08:52.229 [TRACE]  com.itheima.dao.UserMapper.findUserByLike [main] : <==        Row: 6, 蔡徐坤, 12345678, 小菜, 18, 1
2024-01-22 11:08:52.233 [DEBUG]  com.itheima.dao.UserMapper.findUserByLike [main] : <==      Total: 1
2024-01-22 11:08:52.235 [DEBUG]  org.apache.ibatis.transaction.jdbc.JdbcTransaction [main] : Resetting autocommit to true on JDBC Connection [com.mysql.jdbc.JDBC4Connection@2254127a]
2024-01-22 11:08:52.235 [DEBUG]  org.apache.ibatis.transaction.jdbc.JdbcTransaction [main] : Closing JDBC Connection [com.mysql.jdbc.JDBC4Connection@2254127a]
2024-01-22 11:08:52.236 [DEBUG]  org.apache.ibatis.datasource.pooled.PooledDataSource [main] : Returned connection 575935098 to pool.
User{id=6, userName='蔡徐坤', password='12345678', name='小菜', age=18, sex=1}

Process finished with exit code 0