得到參數值的方式來生成圖表

Question

用戶輸入兩個日期 它需要點擊一個按鈕...

如果日期是有效的，同樣的jsp頁面被稱爲有的值在請求中設置好的。 。在本JSP，如果setSeachDone爲真，圖表是產生...

另一servled控制器被要求的圖像...但在該請求已經設置好的值是空

@Controller 
@RequestMapping("/statError") 
public class StatisticError { 

@Autowired 
private IUserService userService; 

@InitBinder("statisticForm") 
protected void initBinder(WebDataBinder binder) { 
    binder.setValidator(new StatisticErrorFormValidator()); 
} 

@RequestMapping(method = RequestMethod.GET) 
public String statistic(Model model) { 
    StatisticErrorForm statisticForm = new StatisticErrorForm(); 
    model.addAttribute("statisticForm", statisticForm); 
    return "statisticError"; 
} 

@RequestMapping(method = RequestMethod.POST) 
public String statistiqueResult(@Valid @ModelAttribute StatisticErrorForm statisticForm, BindingResult result, ModelMap model, HttpServletRequest request, 
    HttpServletResponse response) { 

    if (!result.hasFieldErrors() && !result.hasErrors()) { 

     request.setAttribute("startDate", statisticForm.getStartDate()); 
     request.setAttribute("endDate", statisticForm.getEndDate()); 
     statisticForm.setSearchDone(true); 
    } 

    model.addAttribute(statisticForm); 

    return "statisticError"; 
} 

}

servlet的控制器

@Controller 
@RequestMapping("/statError.jpg") 
public class ImageErrorController { 

@Autowired 
private IUserService userService; 

@RequestMapping(method = RequestMethod.GET) 
public void generateChart(HttpServletRequest request, 
     HttpServletResponse response) { 
    if (request.getAttribute("startDate") != null && request.getAttribute("endDate") != null) { 

     response.setContentType("image/jpg"); 
     AxisChart axisChart = userService.generateChart(); 
     ServletEncoderHelper.encodeJPEG(axisChart, 1.0f, response); 

    } 

}

是有辦法通過發送用戶對imageErrorController輸入的值？ 添加模型generateChart？

Answer 1

你需要將它們傳遞作爲圖像URL的參數，在你看來，像這樣的：

<img src = "<c:url value = "/statError.jpg"> 
     <c:param name = "startDate" value = "${startDate}" /> 
     <c:param name = "endDate" value = "${endDate}" /> 
    </c:url>" />