统一异常处理和最热、最新文章展示，文章归档

统一异常处理和最热、最新文章展示，文章归档 1. 统一异常处理

不管是controller层还是service，dao层，都有可能报异常，如果是预料中的异常，可以直接捕获处理，如果是意料之外的异常，需要统一进行处理，进行记录，并给用户提示相对比较友好的信息。

package com.mszlu.blog.handler;

import com.mszlu.blog.vo.Result;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.ResponseBody;

//对加了@Controller注解的方法进行拦截处理 AOP的实现
@ControllerAdvice
public class AllExceptionHandler {
    //进行异常处理，处理Exception.class的异常
    @ExceptionHandler(Exception.class)
    @ResponseBody //返回json数据
    public Result doException(Exception ex){
        ex.printStackTrace();
        return Result.fail(-999,"系统异常");
    }

}

2. 首页-最热文章

思路：根据观看浏览量多少排序

2.1 接口说明

接口url：/articles/hot

请求方式：POST

请求参数：

参数名称参数类型说明

返回数据：

{
    "success": true,
    "code": 200,
    "msg": "success",
    "data": [
        {
            "id": 1,
            "title": "springboot介绍以及入门案例",
        },
        {
            "id": 9,
            "title": "Vue.js 是什么",
        },
        {
            "id": 10,
            "title": "Element相关",
            
        }
    ]
}

2.2 Controller

首页展示最热文章控制层编写

    @PostMapping("/hot")
    public result hostArticle(){
        int limit = 5;
        return articleService.hostArticle(limit);
    }

2.3 Service

业务层接口于接口实现编写

Result hotArticle(int limit);

    @Override
    public result hostArticle(int limit) {
        LambdaQueryWrapper queryWrapper = new LambdaQueryWrapper<>();
        queryWrapper.select(Article::getId,Article::getTitle);
        queryWrapper.orderByDesc(Article::getViewCounts);
        queryWrapper.last("limit " + limit);
        //select id,title from article order by view_counts desc limit 5
        List articles = articleMapper.selectList(queryWrapper);
        return result.success(copyList(articles,false,false));
    }

2.4 测试

3. 首页-最新文章

思路：根据发表时间先后来排序

3.1 接口说明

接口url：/articles/new

请求方式：POST

请求参数：

参数名称参数类型说明

返回数据：

{
    "success": true,
    "code": 200,
    "msg": "success",
    "data": [
        {
            "id": 1,
            "title": "springboot介绍以及入门案例",
        },
        {
            "id": 9,
            "title": "Vue.js 是什么",
        },
        {
            "id": 10,
            "title": "Element相关",
            
        }
    ]
}

3.1 Controller

控制层代码编写

 
    @PostMapping("new")
    public Result newArticles(){
        int limit = 5;
        return articleService.newArticles(limit);
    }

3.2 Service

业务层接口和接口实现编写

    Result newArticles(int limit);  

@Override
    public Result newArticles(int limit) {
        LambdaQueryWrapper queryWrapper = new LambdaQueryWrapper<>();
        queryWrapper.orderByDesc(Article::getCreateDate);
        queryWrapper.select(Article::getId,Article::getTitle);
        queryWrapper.last("limit "+limit);
        //select id,title from article order by create_date desc limit 5
        List articles = articleMapper.selectList(queryWrapper);

        return Result.success(copyList(articles,false,false));
    }

3.4 测试

4. 首页-文章归档

思路：文章归档即按照年份和月份来划分统计作者发表博客的篇数

4.1接口说明

接口url：/articles/listArchives

请求方式：POST

请求参数：

参数名称参数类型说明

返回数据：

{
    "success": true,
    "code": 200,
    "msg": "success",
    "data": [
        {
            "year": "2021",
            "month": "6",
            "count": 2
        }
            
    ]
}

​

4.1 Controller

控制层代码编写

  
    @PostMapping("listArchives")
    public Result listArchives(){
        return articleService.listArchives();
    }

在dao包下创建一个dos包创建Archives类用来服务于业务层充当泛型

package com.mszlu.blog.dao.dos;

import lombok.Data;

@Data
public class Archives {

    private Integer year;

    private Integer month;

    private Integer count;
}

4.2 Service

业务层的接口和接口实现编写

    Result listArchives();

    @Override
    public Result listArchives() {
        List archivesList = articleMapper.listArchives();
        return Result.success(archivesList);
    }

4.3 Dao

持久层接口代码编写

package com.mszlu.blog.dao.mapper;

import com.baomidou.mybatisplus.core.mapper.baseMapper;
import com.mszlu.blog.dao.pojo.Article;

import java.util.List;
import java.util.Map;

public interface ArticleMapper extends baseMapper {

  List listArchives();

}

持久层对应的xml文件

    
        select year(create_date) as year,month(create_date) as month,count(*) as count from ms_article group by year,month
    

4.4 测试