Spring：返回ModelAndView後ModelAttribute值丟失<form:input>

我面臨這個問題，返回ModelAndView後某些ModelAttribute值會丟失。Spring：返回ModelAndView後ModelAttribute值丟失<form:input>

例子：

這裏是所有的統計項正確填寫。我可以在調試模式下看到每個正確的值。一切似乎是罰款：

ModelAndView mav = new ModelAndView(); 
mav.addObject("materialStatistic", statisticsService.fillStatistic(statisticHelper)); 
return mav;

但在JSP中的數據似乎已丟失：（僅NULL值）

<c:forEach items="${materialStatistic.materialOccurences}" var="occurence" varStatus="occurenceStatus"> 
    <td> 
     <form:input path="materialOccurences[${occurenceStatus.index}].averageM2" cssClass="inputFieldShort"/> 
    </td> 
</c:forEach>

而且很奇怪的是，如果我打印出類似以下領域，我收到了數據：（正確的浮點值）

${occurence.averageM2}

爲什麼<form:input>不能解決我的領域？

更新1：

形式聲明：

<form:form modelAttribute="materialStatistic" action="" id="statistic-material-form" method="POST">

生成的代碼的<form:input>

<input id="materialOccurences20.averageM2" class="inputFieldShort" type="text" value="" name="materialOccurences[20].averageM2">

更新2：

StrictFloatPropertyEditor：

this.getValue()總是空

public class StrictFloatPropertyEditor extends PropertyEditorSupport { 

    private static Log logger = LogFactory.getLog(ProposalService.class); 
    private Locale locale; 
    private boolean allowDigits; 
    private boolean round; 

    public StrictFloatPropertyEditor(boolean allowDigits, boolean round, Locale locale) { 
     this.allowDigits = allowDigits; 
     this.locale = locale; 
     this.round = round; 
    } 

    @Override 
    public void setAsText(String text) throws IllegalArgumentException { 
     Float parsedText = new Float(0); 
     try { 
      DecimalFormat formatter = (DecimalFormat) DecimalFormat.getInstance(locale); 
      if (formatter.getDecimalFormatSymbols().getDecimalSeparator() == ',') { 
       text = text.replaceAll("\\.", ","); 
      } 
      parsedText = formatter.parse(text).floatValue(); 
     } catch (ParseException e) { 
      if (!text.isEmpty()) { 
       logger.error("Parse Exception occured. Value set to zero: " + e.getMessage()); 
      } 
     } 
     super.setValue(parsedText); 
    } 

    @Override 
    public String getAsText() { 
     if(allowDigits){ 
      NumberFormat nf = NumberFormat.getInstance(locale); 
      nf.setGroupingUsed(true); 
      nf.setMinimumFractionDigits(2); 
      String numberAsText = nf.format(this.getValue()); 
      return numberAsText; 
     }else if(round){ 
      float number = (Float) this.getValue(); 
      Integer roundedNumber = Math.round(number); 
      NumberFormat nf = NumberFormat.getInstance(locale); 
      nf.setMinimumFractionDigits(0); 
      String numberAsText = nf.format(roundedNumber); 
      return numberAsText; 
     }else{ 
      NumberFormat nf = NumberFormat.getInstance(locale); 
      nf.setMinimumFractionDigits(0); 
      String numberAsText = nf.format(this.getValue()); 
      return numberAsText; 
     } 
    } 
}

InitBinder：

@InitBinder 
    public void initBinder(HttpServletRequest request, ServletRequestDataBinder binder) { 
     binder.registerCustomEditor(Float.TYPE, "materialOccurences.averageM2", new StrictFloatPropertyEditor(true, true, request.getLocale())); 
    }

來源

2013-12-12 Tunguska

你在HTML中看到什麼？你是否得到了你期望的''標籤？路徑屬性的值是什麼？ – jalynn2

您是否在''之外聲明瞭''來綁定模型屬性？另外，在你的例子中究竟是什麼'null'？ –

創建的輸入標籤正確。如果我在JSP上設置值並將它們傳遞迴控制器，則會導致所有值正確到達。原因是（包括），模型屬性可用。（見更新） – Tunguska

你沒有戰術需要使用Spring標籤。

JSP

<c:forEach items="${materialStatistic.materialOccurences}" var="occurence" varStatus="occurenceStatus"> 
    <td> 
     <input class="inputFieldShort" type="text" value="${occurence.averageM2}" name="materialOccurences[${occurenceStatus.index}].averageM2"> 
    </td> 
</c:forEach>

來源

2013-12-12 15:40:47

問題是我使用Float的自定義PropertyEditor（對於正確的小數）。並且在被覆蓋的'setAsText（）'/'getAsText（）'方法中，我也接收空值。 – Tunguska

摘要：

就目前情況來看，數據獲取控制器和StrictFloatPropertyEditor之間的某處遺失。我猜沒有JSP問題，因爲當我不使用Spring標記時數據被綁定。

控制器：

我可以調試對象UND直視mav.model.materialStatistic.materialOccurences。所有Float值都已正確設置...

@RequestMapping(method = RequestMethod.POST) 
    public ModelAndView loadMaterialStatistic(@ModelAttribute(value="materialStatistic") MaterialStatistic statistic,BindingResult result) { 
     ModelAndView mav = showStatistic(statistic,"tab_material_statistic"); 
     if (!statistic.getSearchHelper().getMaterialNumber().isEmpty()) { 
      MaterialStatistic statisticHelper = new MaterialStatistic(statistic.getSearchHelper()); 
      statisticHelper.setProjectMaterialDao(projectMaterialDao); 
      mav.addObject("materialStatistic", statisticsService.fillStatistic(statisticHelper)); 
     } 
     return mav; 
    }

控制器InitBinder

binder.registerCustomEditor(Float.TYPE, "materialOccurences.averageM2", new StrictFloatPropertyEditor(true, false, request.getLocale()));

StrictFloatPropertyEditor：

..但在PropertyEditorSupport攔截，this.getValue()總是null

@Override 
    public String getAsText() { 
     NumberFormat nf = NumberFormat.getInstance(locale); 
     nf.setGroupingUsed(true); 
     nf.setMinimumFractionDigits(2); 
     String numberAsText = nf.format(this.getValue()); 
    }

來源

2013-12-13 09:00:34 Tunguska

Spring：返回ModelAndView後ModelAttribute值丟失<form:input>

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