废话不多说，直接贴代码：

dao层代码：

mapper：

ListselectByParentId(Integer id);

mapper.xml

select

from easybuy_product_category

where parentId = #{parentId,jdbcType=INTEGER}

Test:

import cn.hd.entity.ProductCategory;

import cn.hd.mapper.ProductCategoryMapper;

import org.junit.Test;

import org.junit.runner.RunWith;

import org.springframework.test.context.ContextConfiguration;

import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

import javax.annotation.Resource;

import java.util.List;

@RunWith(SpringJUnit4ClassRunner.class)

@ContextConfiguration("classpath:applicationContext_dao.xml")

public class productCategoryTest {

@Resource(name = "productCategoryMapper")

private ProductCategoryMapper productCategoryMapper;

@Test

public void fun(){

ListproductCategories = productCategoryMapper.selectByParentId(0);

System.out.println(productCategories);

}

}

service:

ListgetProductCategoryList();

serviceImpl:

package cn.hd.service.impl;

import cn.hd.entity.ProductCategory;

import cn.hd.mapper.ProductCategoryMapper;

import cn.hd.query_vo.productCategoryQueryVo;

import cn.hd.service.ProductCategoryService;

import org.springframework.stereotype.Service;

import javax.annotation.Resource;

import java.util.ArrayList;

import java.util.List;

@Service("productCategoryServiceImpl")

public class ProductCategoryServiceImpl implements ProductCategoryService {

@Resource(name = "productCategoryMapper")

private ProductCategoryMapper productCategoryMapper;

@Override

public ListgetProductCategoryList() {

ListproductCategoryQueryVoList = new ArrayList<>();

ListproductCategory1 = productCategoryMapper.selectByParentId(0);

for (ProductCategory p1 : productCategory1) {

productCategoryQueryVo productCategoryQueryVo = new productCategoryQueryVo();

/*一级分类中的二级分类*/

ListproductCategory2 = productCategoryMapper.selectByParentId(p1.getId());

for (ProductCategory p2 : productCategory2) {

productCategoryQueryVo productCategoryQueryVo1 = new productCategoryQueryVo();

ListproductCategories3 = productCategoryMapper.selectByParentId(p2.getId());

for (ProductCategory p3:productCategories3) {

productCategoryQueryVo productCategoryQueryVo2 = new productCategoryQueryVo();

productCategoryQueryVo2.setProductCategories(p3);

productCategoryQueryVo1.getProductCategoryVoList().add(productCategoryQueryVo2);

}

productCategoryQueryVo1.setProductCategories(p2);

productCategoryQueryVo.getProductCategoryVoList().add(productCategoryQueryVo1);

}

/*封装一级分类 本身*/

productCategoryQueryVo.setProductCategories(p1);

productCategoryQueryVoList.add(productCategoryQueryVo);

}

return productCategoryQueryVoList;

}

}

Test:

import cn.hd.service.ProductCategoryService;

import org.junit.Test;

import org.junit.runner.RunWith;

import org.springframework.test.context.ContextConfiguration;

import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

import javax.annotation.Resource;

@RunWith(SpringJUnit4ClassRunner.class)

@ContextConfiguration("classpath:applicationContext_service.xml")

public class productCategoryTest {

@Resource(name = "productCategoryServiceImpl")

private ProductCategoryService productCategoryService;

@Test

public void fun(){

productCategoryService.getProductCategoryList();

}

}

Controller:

package cn.hd.controller;

import cn.hd.query_vo.productCategoryQueryVo;

import cn.hd.service.ProductCategoryService;

import org.springframework.stereotype.Controller;

import org.springframework.ui.Model;

import org.springframework.web.bind.annotation.RequestMapping;

import javax.annotation.Resource;

import java.util.List;

@Controller

public class ProductCategoryController {

@Resource(name = "productCategoryServiceImpl")

private ProductCategoryService productCategoryService;

@RequestMapping("/index")

public String index(Model model){

ListproductCategoryVoList = productCategoryService.getProductCategoryList();

model.addAttribute("productCategoryVoList",productCategoryVoList);

return "jsp/pre/index.jsp";

}

}

JSP

数据库设计