Spring 基于Session的创建实例

需求

提供一个网页，根据导入的Excel数据计算结果。

第一版本设计

Controller层

@RestController
public class QuoteController {
    private static Logger logger = LoggerFactory.getLogger(QuoteController.class.getName());
    private String SESSION_KEY_QUOTE = "quote";
    private String SESSION_KEY_QUOTE_RESULT = "quote_result";
    @Autowired
    QuoteService quoteService;

    //报价数据导入
    @RequestMapping(value = "quote/import", method = RequestMethod.POST)
    public String quoteImport(MultipartFile file, Double ratio) {
        // 判断文件是否为空
        if(!file.isEmpty()){
            try {
                List<QuoteItem> items = quoteService.upload(file);
                List<QuoteCacResult> cacResult = quoteService.calculate(items, ratio);

                HttpServletRequest request = ((ServletRequestAttributes) RequestContextHolder.getRequestAttributes()).getRequest();
                request.getSession().setAttribute(SESSION_KEY_QUOTE, items);
                request.getSession().setAttribute(SESSION_KEY_QUOTE_RESULT, cacResult);

            } catch (Exception e) {
                logger.error(e.getMessage());
                return e.getMessage();
            }
        }

        return "success";
    }

    @RequestMapping(value = "quote/recalculate", method = RequestMethod.POST)
    public String recalculate(Double ratio){
        CommonResult<List<QuoteCacResult>> result = new CommonResult<>();
        HttpServletRequest request = ((ServletRequestAttributes) RequestContextHolder.getRequestAttributes()).getRequest();

        if (request.getSession().getAttribute(SESSION_KEY_QUOTE) != null){
            List<QuoteItem> items = (List<QuoteItem>)request.getSession().getAttribute(SESSION_KEY_QUOTE);
            List<QuoteCacResult> cacResult = quoteService.calculate(items, ratio);
            request.getSession().setAttribute(SESSION_KEY_QUOTE_RESULT, cacResult);
        }

        return "success";
    }

    @RequestMapping(value = "quote/result", method = RequestMethod.GET)
    public CommonResult<List<QuoteCacResult>> quoteCala(){
        CommonResult<List<QuoteCacResult>> result = new CommonResult<>();
        HttpServletRequest request = ((ServletRequestAttributes) RequestContextHolder.getRequestAttributes()).getRequest();

        if (request.getSession().getAttribute(SESSION_KEY_QUOTE_RESULT) == null) {
            result.setData(new ArrayList<>());
        }else {
            List<QuoteCacResult> data = (List<QuoteCacResult>)request.getSession().getAttribute(SESSION_KEY_QUOTE_RESULT);
            result.setData(data);
        }

        return result;
    }
}

Service层

存在的问题

1，导入的数据通过参数返回给计算函数，没有对象数据的封装

2，Controller存在大量关于Session存储、获取代码

改进版本

 Controller层

@RestController
public class QuoteController {
    private static Logger logger = LoggerFactory.getLogger(QuoteController.class.getName());
    @Autowired
    private QuoteService quoteService;

    //报价数据导入
    @RequestMapping(value = "quote/import", method = RequestMethod.POST)
    public String quoteImport(MultipartFile file, Double ratio) {
        // 判断文件是否为空
        if(!file.isEmpty()){
            try {
                quoteService.upload(file);
                quoteService.calculate(ratio);
            } catch (Exception e) {
                logger.error(e.getMessage());
                return e.getMessage();
            }
        }

        return "success";
    }

    @RequestMapping(value = "quote/recalculate", method = RequestMethod.POST)
    public String recalculate(Double ratio){
        quoteService.calculate(ratio);
        return "success";
    }

    @RequestMapping(value = "quote/result", method = RequestMethod.GET)
    public CommonResult<List<QuoteCacResult>> quoteCala(){
        CommonResult<List<QuoteCacResult>> result = new CommonResult<>();
        result.setData(quoteService.getCalcResult());
        return result;
    }
}

Servie层

总结

1, 改进版本更简洁，更面向对象

2，注意calcResult必须声明封装get,set方法。否则proxy不起作用，参见

https://stackoverflow.com/questions/39488124/how-to-use-session-scoped-component-in-controller

3, 采用Spring Boot搭建的项目，无须配置RequestContextListener上面代码就能生效。