tkMaper通用Mapper详细使用，可以不用你在写sql语句

Posted 2021-09-04 SmallCuteMonkey

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tkMapper使用通用Mapper使用

需要提前的添加Mybatis的依赖，因为tkMapper是基于Mybatis框架的

1.1添加依赖

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.5.1</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
<!--tkMapper的使用-->
    <dependencies>
        <dependency>
            <groupId>tk.mybatis</groupId>
            <artifactId>mapper-spring-boot-starter</artifactId>
            <version>2.0.4</version>
        </dependency>

<!--        mybaits-->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.0.1</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-test</artifactId>
        </dependency>

        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>

        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.45</version>
        </dependency>
    </dependencies>

1.2增加启动类的注解@MapperScan tk.mybatis.spring.annotation.MapperScan;

package com.hou;


import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import tk.mybatis.spring.annotation.MapperScan;

@SpringBootApplication
@MapperScan("com.hou.dao")
public class Application {
    public static void main(String[] args) {
        SpringApplication.run(Application.class,args);
    }
}

1.3创建实体类

如果类名和表名一致可以不用加上@Table， @Id
@GeneratedValue(strategy = GenerationType.IDENTITY)这个是主键自增的生成策略。@Column(name="") 可以和数据库的字段进行配置

package com.hou.pojo;


import lombok.Data;
import org.springframework.format.annotation.DateTimeFormat;

import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;
import java.util.Date;
import java.util.List;

@Data

public class User {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    Integer id;
    String username;
    String password;
    @DateTimeFormat(pattern = "yyyy-MM-dd")
    Date Birthday;

    List<Orders> ordersList;

}

package com.hou.pojo;

import lombok.Data;

@Data
public class Orders {
    private Integer orderId;
    private Integer userId;
    private String receiverName;
    private String receiver_address;
    private String totalAmount;

}

package com.hou.pojo;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

import javax.persistence.Column;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;

@Data
@AllArgsConstructor
@NoArgsConstructor
public class Category {
    @Id
//    可以使用主键自增策略
    @GeneratedValue(strategy = GenerationType.IDENTITY)

//    这个属性可以和数据库的字段相匹配
    @Column(name = "category_id")
    private int  categoryId;
    private String categoryName;
    @Column(name = "category_level")
    private int categoryLevel;
    private  int categoryIcon;
    private String categorySlogan;
    private String categoryPic;
    private String categoryBgColor;

}

结构图：

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1.4创建Dao接口

package com.hou.dao;

import com.hou.general.GeneralDao;
import com.hou.pojo.Category;
import tk.mybatis.mapper.common.Mapper;
import tk.mybatis.mapper.common.MySqlMapper;

public interface CategoryDao extends GeneralDao<Category> {
}

package com.hou.dao;

import com.hou.general.GeneralDao;
import com.hou.pojo.Orders;
import tk.mybatis.mapper.common.Mapper;


public interface OrderDao extends GeneralDao<Orders> {
}

package com.hou.dao;

import com.hou.general.GeneralDao;
import com.hou.pojo.User;
import tk.mybatis.mapper.common.Mapper;
import tk.mybatis.mapper.common.MySqlMapper;

public interface UserDao extends GeneralDao<User> {
//    自定义查询

    User queryByUserName(String username);

}

package com.hou.general;

import tk.mybatis.mapper.common.Mapper;
import tk.mybatis.mapper.common.MySqlMapper;

public interface GeneralDao<T> extends Mapper<T>, MySqlMapper<T> {
}

1.5通过Example进行查询

注意criteria.andEqualto(Property,value),和orEqualto(Property,value)的区别 andLike(类的属性名，"%mohu%")和orLike(类的属性名，value)的区别

package com.hou.controller;


import com.hou.dao.CategoryDao;
import com.hou.pojo.Category;
import org.apache.ibatis.session.RowBounds;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import tk.mybatis.mapper.entity.Example;

import java.util.List;

@Controller
@ResponseBody
public class CategoryController {

    @Autowired
    CategoryDao categoryDao;
/*

    @RequestMapping("listcategory")
    public List<Category> list(){
        Category category=new Category();

        category.setCategoryName("家具");
        category.setCategoryBgColor("black");
        category.setCategoryLevel(1);
        category.setCategoryIcon(2);
        category.setCategoryPic("img/1.jpg");
        category.setCategorySlogan("hahah");
//        categoryDao.insert(category);
        categoryDao.insertUseGeneratedKeys(category);

        List<Category> categories = categoryDao.selectAll();
        return categories;

    }

    @RequestMapping("updateCategory")
    public int totestUpate(){
        Category category=new Category();
        category.setCategoryId(1);
        category.setCategoryName("水果");
        category.setCategoryBgColor("black");
        category.setCategoryLevel(1);
        category.setCategoryIcon(2);
        category.setCategoryPic("img/1.jpg");
        category.setCategorySlogan("hahah");
        int i = categoryDao.updateByPrimaryKey(category);
        System.out.println(i);
        return i;


    }

    @RequestMapping("deletcategory")
    public int delete(){
        int i = categoryDao.deleteByPrimaryKey(1);


        return i;


    }
*/


//    使用Example例子进行相关的增删改查

    @RequestMapping("selectByExample")
    public List<Category> selectByExample(){


        Example example=new Example(Category.class);
        Example.Criteria criteria = example.createCriteria();
//        property为类的属性值,value加上类的条件
//        查询等级为1的category
        criteria.andEqualTo("categoryLevel",1);
//        查询等级或者为2
        criteria.orEqualTo("categoryLevel",2);

        List<Category> categorielist = categoryDao.selectByExample(example);


        return categorielist;


    }

    @RequestMapping("selectByExample1")
    public List<Category> selectByExample1(){


        Example example=new Example(Category.class);
        Example.Criteria criteria = example.createCriteria();
//        property为类的属性值,value加上类的条件
//        进行模糊查询
//        用and进行连接的必须满足这个两个条件的查询
        criteria.andEqualTo("categoryLevel",1);
        criteria.andLike("categoryName","%果%");

        criteria.orLike("categoryName","%家%");

        List<Category> categorielist = categoryDao.selectByExample(example);


        return categorielist;


    }

//    进行分页查询
    @RequestMapping("selectByExamplePage")
    public List<Category> selectByExamplePage(){
        int pageNum=1;
        int pageSize=2;
//从第几条开始查询
        int start= (pageNum-1)*pageSize;
        RowBounds rowBounds=new RowBounds(start,pageSize);


        List<Category> list = categoryDao.selectByRowBounds(new Category(), rowBounds);

//        查询总记录数
        int i = categoryDao.selectCount(new Category());

        System.out.println(i);


        return list;


    }



}

1.6通过selectByRowBounds(new Category(), rowBounds)进行分页的查询

//    进行分页查询
    @RequestMapping("selectByExamplePage")
    public List<Category> selectByExamplePage(){
        int pageNum=1;
        int pageSize=2;
//从第几条开始查询
        int start= (pageNum-1)*pageSize;
        RowBounds rowBounds=new RowBounds(start,pageSize);


        List<Category> list = categoryDao.selectByRowBounds(new Category(), rowBounds);

//        查询总记录数
        int i = categoryDao.selectCount(new Category());

        System.out.println(i);


        return list;


    }

1.7通过selectByExampleAndRowBounds（example,rowBounds）进行条件分页查询

//    进行条件和分页查询 selectByExampleAndRowBounds()
    @RequestMapping("selectByExampleAndRowBounds")
    public List<Category> select(){
//        带上条件的分页，需要先满足条件然后再进行分页
        Example example=new Example(Category.class);
        Example.Criteria criteria = example.createCriteria();
        criteria.andEqualTo("categoryLevel",1);




        int pageNum=1;
        int pageSize=2;

        int start=(pageNum-1)*pageSize;

        RowBounds rowBounds=new RowBounds(start,pageSize);

        List<Category> list = categoryDao.selectByExampleAndRowBounds(example, rowBounds);

        int i = categoryDao.selectCountByExample(example);
        System.out.println(i);


        return list;


    }

1.8通用mapper自定义的查询

直接在UserDao中写上自定义的方法

在resources下面建立mapper目录，下面建立相应的文件UserMapper.xml

需要在application.yml中的mybatis的mapper-location的相应的配置不要写错

mybatis:
  type-aliases-package: com.hou.pojo
  mapper-locations: classpath:mapper/*Mapper.xml

3.UserMapper.xml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">
<mapper namespace="com.hou.dao.UserDao">
    <resultMap id="userResultMap" type="User">
        <id property="id" column="id"/>
        <result property="username" column="username"/>
        <result property="password" column="password"/>
      <collection property="ordersList" ofType="Orders" resultMap="orderResultMap"/>



    </resultMap>
    <resultMap id="orderResultMap" type="Orders">
        <id property="orderId" column="order_id"/>
        <result property="userId" column="user_id"/>
        <result property="receiverName" column="receiver_name"/>
        <result property="totalAmount" column="total_amount"/>



    </resultMap>



    <select id="queryByUserName" resultMap="userResultMap" parameterType="java.lang.String" >

    select *from user u,orders o where u.id=o.user_id and username=#{username};

</select>



</mapper>

1.9测试文件RestController进行相关的测试，用Json数据回显到前端

package com.hou.controller;


import com.hou.dao.OrderDao;
import com.hou.dao.UserDao;
import com.hou.pojo.Orders;
import com.hou.pojo.User;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;
import tk.mybatis.mapper.entity.Example;

import java.util.List;

@RestController
public class UserController {
    @Autowired
    UserDao userDao;

    @Autowired
    private OrderDao orderDao;
    @RequestMapping("queryOrdersByUserName")
    public List<Orders> OneToMany(){
        Example example = new Example(User.class);
        Example.Criteria criteria = example.createCriteria();
        criteria.andEqualTo("username","侯芳");

//        1.根据用户名查询到users
        List<User> users = userDao.selectByExample(example);

        User user = users.get(0);//因为知道username只有一个

//        2.根据users查询到userId，然后在Orders中进行查询订单的信息
        Example example1 = new Example(Orders.class);
        Example.Criteria criteria1 = example1.createCriteria();
        criteria1.andEqualTo("userId",user.getId());

        List<Orders> orders = orderDao.selectByExample(example1);

//        3.将查询到的orders放入User中
        user.setOrdersList(orders);

//        4. 打印user
        System.out.println(user);
	   return orders;
}

//    自定义的查询
@RequestMapping("queryByMyself")
  public User queryByMyself(){
    User user = userDao.queryByUserName("admin");
    return user;
}

}

package com.hou.controller;


import com.hou.dao.CategoryDao;
import com.hou.pojo.Category;
import org.apache.ibatis.session.RowBounds;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import tk.mybatis.mapper.entity.Example;

import java.util.List;

@Controller
@ResponseBody
public class CategoryController {

    @Autowired
    CategoryDao categoryDao;
/*

    @RequestMapping("listcategory")
    public List<Category> list(){
        Category category=new Category();

        category.setCategoryName("家具");
        category.setCategoryBgColor("black");
        category.setCategoryLevel(1);
        category.setCategoryIcon(2);
        category.setCategoryPic("img/1.jpg");
        category.setCategorySlogan("hahah");
//        categoryDao.insert(category);
        categoryDao.insertUseGeneratedKeys(category);

        List<Category> categories = categoryDao.selectAll();
        return categories;

    }

    @RequestMapping("updateCategory")
    public int totestUpate(){
        Category category=new Category();
        category.setCategoryId(1);
        category.setCategoryName("水果");
        category.setCategoryBgColor("black");
        category.setCategoryLevel(1);
        category.setCategoryIcon(2);
        category.setCategoryPic("img/1.jpg");
        category.setCategorySlogan("hahah");
        int i = categoryDao.updateByPrimaryKey(category);
        System.out.println(i);
        return i;


    }

    @RequestMapping("deletcategory")
    public int delete(){
        int i = categoryDao.deleteByPrimaryKey(1);


        return i;


    }
*/


//    使用Example例子进行相关的增删改查

    @RequestMapping("selectByExample")
    public List<Category> selectByExample(){


        Example example=new Example(Category.class);
        Example.Criteria criteria = example.createCriteria();
//        property为类的属性值,value加上类的条件
//        查询等级为1的category
        criteria.andEqualTo("categoryLevel",1);
//        查询等级或者为2
        criteria.orEqualTo("categoryLevel",2);

        List<Category> categorielist = categoryDao.selectByExample(example);


        return categorielist;


    }

    @RequestMapping("selectByExample1")
    public List<Category> selectByExample1(){


        Example example=new Example(Category.class);
        Example.Criteria criteria = example.createCriteria();
//        property为类的属性值,value加上类的条件
//        进行模糊查询
//        用and进行连接的必须满足这个两个条件的查询
        criteria.andEqualTo("categoryLevel",1);
        criteria.andLike("categoryName","%果%");

        criteria.orLike("categoryName","%家%");

        List<Category> categorielist = categoryDao.selectByExample(example);


        return categorielist;


    }

//    进行分页查询
    @RequestMapping("selectByExamplePage")
    public List<Category> selectByExamplePage(){
        int pageNum=1;
        int pageSize=2;
//从第几条开始查询
        int start= (pageNum-1)*pageSize;
        RowBounds rowBounds=new RowBounds(start,pageSize);


        List<Category> list = categoryDao.selectByRowBounds(new Category(), rowBounds);

//        查询总记录数
        int i = categoryDao.selectCount(new Category());

        System.out.println(i);


        return list;


    }

//    进行条件和分页查询 selectByExampleAndRowBounds()
    @RequestMapping("selectByExampleAndRowBounds")
    public List<Category> select(){
//        带上条件的分页，需要先满足条件然后再进行分页
        Example example=new Example(Category.class);
        Example.Criteria criteria = example.createCriteria();
        criteria.andEqualTo("categoryLevel",1);




        int pageNum=1;
        int pageSize=2;

        int start=(pageNum-1)*pageSize;

        RowBounds rowBounds=new RowBounds(start,pageSize);

        List<Category> list = categoryDao.selectByExampleAndRowBounds(example, rowBounds);

        int i = categoryDao.selectCountByExample(example);
        System.out.println(i);


        return list;


    }













}

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