tkMapper 简记

tkMapper 实现基本CRUD操作以及分页查询和联表查询方法

- - 目录
  - - 1. tkMapper


package com.sh;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
/*mapperscan 注意：用tk.mybatis.spring.annotation.MapperScan*/
import tk.mybatis.spring.annotation.MapperScan;

@MapperScan("com.sh.dao")
@SpringBootApplication
public class TkMapperDemoApplication {
        
        

    public static void main(String[] args) {
        
        
        SpringApplication.run(TkMapperDemoApplication.class, args);
    }

}

4. tkMapper 使用

创建数据表
创建实体类
创建 Dao 接口
- tkMapper 已经完成了对单表的通用操作的封装封装在 Myapper 接口和 MysqlMapper 接口；因此我们要完成单表的操作，只需自定义 Dao ji恶口继承 Mapper 接口和 MysqlMapper 接口
```
public interface UserDao extends Mapper<Users>, MySqlMapper<Users> {
}
```

测试

@Test
    public void test(){
      
      
        Users users = new Users();
        users.setUsername("saaa");
        users.setPassword("111");
        users.setUserImg("img/");
        users.setUserRegtime(new Date());
        users.setUserModtime(new Date());
        int i = userDao.insert(users);
        System.out.println(i);
       
    }

5. tkMapper 提供的方法

单表

package com.sh.dao;

import com.sh.TkMapperDemoApplication;
import com.sh.beans.Category;
import org.apache.ibatis.session.RowBounds;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;
import tk.mybatis.mapper.entity.Example;

import java.util.List;

import static org.junit.Assert.*;

/**
 * @Author Mr.suho
 * @Date 2022/4/22 10:52
 * @Description CategoryDaoTest
 * @Version 1.0
 */
@RunWith(SpringRunner.class)
@SpringBootTest(classes = TkMapperDemoApplication.class)
public class CategoryDaoTest {
    @Autowired
    CategoryDao categoryDao;
    /*添加*/
    @Test
    public void testInsert(){
        Category category = new Category(0,"测试3",1,0,"01.png","hehe","aaa.png","black");
        //int i = categoryDao.insert(category);
        /*
        * id 回填：添加操作时，可以取到添加的这条数的id
        * 条件：在实体标注哪个是 id 字段，@Id
        * */
        int a = categoryDao.insertUseGeneratedKeys(category);
        System.out.println("当前添加数据的id："+category.getCategoryId());
        assertEquals(1,a);//断言：判断返回值和期望值是否相等
    }
    /*修改*/
    @Test
    public void testUpdate(){
        Category category = new Category(57,"测试5",1,0,"0dadsdada1.png","hehe","aaa.png","black");
        int i = categoryDao.updateByPrimaryKey(category);
        assertEquals(1,i);
    }
    /*删除*/
    @Test
    public void testDelete(){
        int i = categoryDao.deleteByPrimaryKey(56);
        assertEquals(1,i);
    }
    /*查询*/
    @Test
    public void testSelect1(){
        /*查询所有*/
        //java8 写法
        categoryDao.selectAll().stream().forEach(c ->{
            System.out.println(c);
        });
        /*for循环遍历数据*/
        List<Category> categories = categoryDao.selectAll();
        for (Category c: categories
             ) {
            System.out.println(c);
        }
        /*根据id（主键）查询*/
        Category category = categoryDao.selectByPrimaryKey(57);
        System.out.println("-------"+category);

        /*条件查询
        * 1.创建一个 Example 封装，类别 Category 条件查询
        * */
        Example example = new Example(Category.class);
        Example.Criteria criteria = example.createCriteria();
        //查询等级等于 1 和（并且）分类名称中包含“干“的数据
        //注意：和，并且 and，或者 or
        criteria.andEqualTo("categoryLevel",1);
        criteria.andLike("categoryName","%干%");
        List<Category> categories1 = categoryDao.selectByExample(example);
        for (Category c: categories1
             ) {
            System.out.println(c);
        }

        /*分页查询*/
        int pageNum = 2; //条数
        int pageSize = 10; //页数
        int start = (pageNum - 1) * pageSize;
        RowBounds rowBounds = new RowBounds(start,pageSize);
        List<Category> categories2 = categoryDao.selectByRowBounds(new Category(), rowBounds);
        for (Category cs: categories2
             ) {
            System.out.println(cs);
        }
        /*查询记录总数-所有*/
        int i = categoryDao.selectCount(new Category());
        System.out.println("-----总数："+i);

        /*带条件分页查询*/
        //条件
        Example example1 = new Example(Category.class);
        Example.Criteria criteria1 = example.createCriteria();
        criteria.andEqualTo("categoryLevel",1); //条件：为等级等于 1
        //分页
        int pageNum1 = 1; //条数
        int pageSize1 = 3; //页数
        int start1 = (pageNum1 - 1) * pageSize1;
        RowBounds rowBounds1 = new RowBounds(start1,pageSize1);
        List<Category> categories3 = categoryDao.selectByExampleAndRowBounds(example1, rowBounds1);
        for (Category a: categories3
        ) {
            System.out.println(a);
        }
        /*查询记录总数-满足条件的*/
        int s = categoryDao.selectCountByExample(example1);
        System.out.println("-----总数："+s);
    }
}

联表

所有关联查询都可以通过多个单表实现操作

   //查询用户同时查询订单
        Example example = new Example(Users.class);
        Example.Criteria criteria = example.createCriteria();
        criteria.andEqualTo("username","zhansan");
        //1.根据用户名查询用户信息
        List<Users> users = userDao.selectByExample(example);
        Users users1 = users.get(0);
        //2.根据用户 id 到订单表查询订单信息
        Example example1 = new Example(Orders.class);
        Example.Criteria criteria1 = example1.createCriteria();
        criteria1.andEqualTo("userId",users1.getUserId());
        List<Orders> orders = ordersDao.selectByExample(example1);
        //3.将查询到的订单集合设置到 Users 中
        users1.setOrderList(orders);
        System.out.println(users1);

自定义连接查询：

在使用 tkMapper.Dao 继承 Mapper 和 MysqlMapper 之后，还可以自定义查询

步骤
- 创建 dao 接口
- 创建 Mapper.xml 文件自己写SQL

tkMapper 实现基本CRUD操作以及分页查询和联表查询方法

目录

1. tkMapper

2. tkMapper 简介

3. tkMapper 整合

4. tkMapper 使用

5. tkMapper 提供的方法

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