SSM框架项目实践

学习目标：

SSM框架项目实践

学习了基于二分搜索树对于集合的实现

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学习内容：

实现CategoryService分类数据查询，开发了BooksService实现图书分类查询

核心代码如下：

package com.imooc.reader.service.impl;

import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.imooc.reader.entity.Category;
import com.imooc.reader.mapper.CategoryMapper;
import com.imooc.reader.service.CategoryService;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Propagation;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.Resource;
import java.util.List;

@Service
@Transactional(propagation = Propagation.NOT_SUPPORTED,readOnly = true)
public class CategoryServiceImpl implements CategoryService {
    @Resource
    private CategoryMapper categoryMapper;
    @Override
    public List<Category> selectAll() {
        QueryWrapper wrapper = new QueryWrapper();
        wrapper.orderByAsc("category_id");
        return categoryMapper.selectList(wrapper);
    }
}

package com.imooc.reader.service.impl;

import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.imooc.reader.entity.Book;
import com.imooc.reader.mapper.BookMapper;
import com.imooc.reader.service.BookService;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Propagation;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.Resource;

@Service
@Transactional(propagation = Propagation.NOT_SUPPORTED,readOnly = true)
public class BookServiceImpl implements BookService {
    @Resource
    private BookMapper bookMapper;
    @Override
    public IPage<Book> selectPage(Long categoryId, String order, Integer page, Integer rows) {
        IPage<Book> p = new Page<>(page,rows);
        QueryWrapper<Book> wrapper = new QueryWrapper<>();
        if(categoryId!=null&&categoryId!=-1){
            wrapper.eq("category_id", categoryId);
        }
        if (order != null) {
            if (order.equals("quantity")) {
                wrapper.orderByDesc("evaluation_quantity");
            } else if (order.equals("score")) {
                wrapper.orderByDesc("evaluation_score");
            }
        }else {
            wrapper.orderByDesc("evaluation_quantity");
        }
        p=bookMapper.selectPage(p, wrapper);
        return p;
    }
}

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学习时间：

08：00-11：50   13：30-15：00 17：00-17：30

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学习产出：

熟悉了SSM框架开发项目的基本流程，对于代码的业务逻辑有了一定的认识。