Java方向（SSM+SpringBoot）项目实训Day12-SpringBoot（新闻管理系统）归档+异常处理+登录拦截

Java方向（SSM+SpringBoot）项目实训
Day12（2020.8.2）

归档（按新闻年份归档）

1.数据库中测试按年份分类排序语句；
点击右侧Database；

点击Query Console下选择console（Default）；

点开t_news表手动修改几条新闻的年份以做年份归档SQL语句测试，后点击Submit提交数据更新；

在刚才打开的console（Default）页面键入如下SQL语句测试新闻的年份归档，点击Execute执行；

select date_format(n.update_time,'%Y') from t_news n group by date_format(n.update_time,'%Y') order by date_format(n.update_time,'%Y') desc
//从时间戳年月日+时分秒格式中提取出year分组降序

select * from t_news n where date_format(n.update_Time,'%Y') = 2020
//归档某一具体年份的所有新闻

测试结果如下；

2.修改NewRepository接口；
NewRepository：中添加

        //select date_format(n.update_time,'%Y') from t_news n group by date_format(n.update_time,'%Y') order by date_format(n.update_time,'%Y') desc
    @Query("select function('date_format',n.updateTime,'%Y') as year from News n group by year order by year desc")
    List<String> findGroupYear();

    @Query("select n from News n where function('date_format',n.updateTime,'%Y') = ?1 ")
    List<News> findByYear(String year);

2.修改NewService接口；
NewService：中添加

    List<Comment> listCommentByNewId(Long newId);

3.修改NewServiceImpl类；
NewServiceImpl：中添加

    @Override
    public List<Comment> listCommentByNewId(Long newId) {
     
        Sort sort = Sort.by("createTime");
        List<Comment> comments = commentRepository.findByNewsIdAndParentCommentNull(newId,sort);
        return eachComment(comments);
    }

    private List<Comment> eachComment(List<Comment> comments){
     
        List<Comment> commentsView = new ArrayList<>();
        for (Comment comment:comments){
     
            Comment c = new Comment();
            BeanUtils.copyProperties(comment,c);
            commentsView.add(c);
        }
        //合并评论的各层子代到第一级子代集合中
        combineChildren(commentsView);
        return commentsView;
    }

    private void combineChildren(List<Comment> comments){
     
        for (Comment comment:comments){
     
            List<Comment> replys1 = comment.getReplyComments();
            for (Comment reply1:replys1){
     
                //循环迭代，找出子代
                recursively(reply1);
            }
            comment.setReplyComments(tempReplys);
            //清楚临时缓存区
            tempReplys = new ArrayList<>();
        }
    }

    private List<Comment> tempReplys = new ArrayList<>();

    private void recursively(Comment comment){
     
        tempReplys.add(comment);  //顶节点添加到临时存放区
        if (comment.getReplyComments().size()>0){
     
            List<Comment> replys = comment.getReplyComments();
            for (Comment reply:replys){
     
                tempReplys.add(reply);
                if(reply.getReplyComments().size()>0){
     
                    recursively(reply);
                }
            }
        }
    }

4.web下创ArchiveShowController类；

ArchiveShowController：中添加

    @GetMapping("/comments/{newId}")
    public String comments(@PathVariable Long newId, Model model){
     
        model.addAttribute("comments",commentService.listCommentByNewId(newId));
        return "new::commentList";

    }

Test
1.点击新闻主页上方导航栏中的归档，即可查看按年份归档的新闻；

2.也可点击新闻进入新闻详情页；

异常处理

1.news下创建NotFoundException类进行全局异常处理；

NotFoundException中添加：

@ResponseStatus(HttpStatus.NOT_FOUND)
public class NotFoundException extends RuntimeException {
     

    public NotFoundException() {
     
    }

    public NotFoundException(String message) {
     
        super(message);
    }

    public NotFoundException(String message, Throwable cause) {
      //cause 异常原因
        super(message, cause);
    }
}

2.news下创建handler包下创建ControllerExceptionHandler类；

ControllerExceptionHandler中添加：

@ControllerAdvice
public class ControllerExceptionHandler {
     

    private final Logger logger = LoggerFactory.getLogger(this.getClass());

    @ExceptionHandler(Exception.class)
    public ModelAndView exceptionHandler(HttpServletRequest request, Exception e) throws Exception {
     

        logger.error("Request: URL: {},Exception: {}",request.getRequestURL(),e);
        if (AnnotationUtils.findAnnotation(e.getClass(), ResponseStatus.class)!=null){
     
            throw e;
        }
        ModelAndView mv = new ModelAndView();
        mv.addObject("url",request.getRequestURL());
        mv.addObject("exception",e);
        mv.setViewName("/error/error");
        return mv;
    }
}

Test
手动添加一些错误；

404页面；

错误页面；

控制台日志；

登录拦截

拦截器：
依赖web框架
面向切面编程（AOP）

1.news下创建interceptor包下创建LoginInterceptor类；

LoginInterceptor中添加：

public class LoginInterceptor extends HandlerInterceptorAdapter {
     

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response,Object handler) throws  Exception{
     

        if (request.getSession().getAttribute("user")==null){
     
            response.sendRedirect("/admin");
            return false;
        }
        return true;
    }
}

2.interceptor下创建WebConfig类；

WebConfig中添加：

@Configuration
public class WebConfig implements WebMvcConfigurer {
     

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
     
        registry.addInterceptor(new LoginInterceptor()).addPathPatterns("/admin/**")
                .excludePathPatterns("/admin")
                .excludePathPatterns("/admin/login");
    }
}

Test
1.不登录，直接从新闻主页，输入地址跳转至新闻管理页面；

2.登录拦截成功，跳转至新闻管理页面失败，而是跳转至用户登录界面；