更改 ModelAttribute 名称后 BindingResult 不起作用

Question

当使用默认的 ObjectName 时，如下所示：

model.addAttribute(myObject);

BindingResult会将错误结果绑定到对应的输入路径，对象名为myObject。

但是如果我为我的对象使用一个新名称，如下所示：

model.addAttribute("newObjectName",myObject);

BindingResult 仍会将其对象名称设置为 myObject，而不是“newObjectName”，并且不会绑定结果错误。

那么，有没有什么方法可以让 BindingResult 工作而不将模型对象名称更改为默认值呢？

我的控制器

@RequestMapping(value="unit/unitAdd.do", method=RequestMethod.POST)
    public final String saveUnitAdd(@Valid PmiUnit pmiUnit,Model model,BindingResult bindingResult,HttpServletRequest httpServletRequest,
            HttpSession session){
    logger.info("saveAddUnit called!");
    boolean exists = unitService.isAlreadyExists("pmi_units",   "uni_unit_name_pk",pmiUnit.getUniUnitNamePk());
    if (exists) {
        //exists and without state DEL, return exists error
        logger.info("Unit Name_PK exists");
        if(!unitService.isExistsAndDeleted("pmi_units", "uni_unit_name_pk",pmiUnit.getUniUnitNamePk())){
            System.out.println("exists and not deleted");
            bindingResult.rejectValue("uniUnitNamePk", "pmi.validator.constraints.unique");}
        //exists but with state DEL, update this row
        else{
            unitService.updateDeletedUnit(pmiUnit);
            mainService.getDefaultPmiUnit(pmiUnit, model);
            httpServletRequest.setAttribute("fromAddUnit", "true");
            httpServletRequest.setAttribute("addResult", "true");
            model.addAttribute("pmiUnit",pmiUnit);
            return "accessControl1/unit/unitManage";
        }
    }
    //if has errors, return the same page
    if (bindingResult.hasErrors()) {
        model.addAttribute("pmiUnit",pmiUnit);
        return "accessControl1/unit/unitAdd";
    }

JSP部分

<form:form method="POST" id="pmiAddUnit" name="pmiAddUnit"
            modelAttribute="pmiUnit" enctype="multipart/form-data"
            action="unitAdd.do">
...
<table>
    <tr>
    <td align="left"><form:input id="uniUnitNamePk" name="uniUnitNamePk" path="uniUnitNamePk" class="margin-right-ten" /></td>
    <td align="left"><form:errors class="error" path="uniUnitNamePk" /></td>
    </tr>
</table>
...
</form:form>

导入** .domain.PmiUnit; 在domain包中，pmiUnit的类名为PmiUnit。因此，如果我将 modelAttribute 名称更改为“pmiUnitObject”。（好吧，这只是我更喜欢这种方式，不喜欢具有不可更改名称的固定默认方式。而且，如果您添加多个对象，您应该能够使用像${variableName.propertyName}.jsp 中的bean ）

我这样修改：

model.addAttribute("pmiUnitObject",pmiUnit);

这是调试期间的变量 BindingResult：

……不好意思，发不了图……

不管怎样，你会看到在 bindingResult.objectName 中它仍然是“pmiUnit”，并且它不会将错误结果绑定到 jsp form:errors 标记。

Answer 1

您没有模型属性，只是碰巧有一个任意方法参数@Valid。除此之外，您的方法参数的顺序也存在问题。必须BindingResult直接跟在它所适用的论点之后，在您的情况下是PmiUnit论点。另请参阅参考指南的这一部分。

public final String saveUnitAdd(@Valid PmiUnit pmiUnit,BindingResult bindingResult,,Model modelHttpServletRequest httpServletRequest, HttpSession session){ ... }

接下来@Valid添加@ModelAttribute和删除model.addAttribute呼叫。

public final String saveUnitAdd(@Valid @ModelAttribute PmiUnit pmiUnit,BindingResult bindingResult,Model model,HttpServletRequest httpServletRequest, HttpSession session){ ... }

如果您想给它另一个名称，请将其包含在@ModelAttribute注释中。默认值是采用方法参数的名称。

public final String saveUnitAdd(@Valid @ModelAttribute("your-name-here") PmiUnit pmiUnit,BindingResult bindingResult,Model model,HttpServletRequest httpServletRequest, HttpSession session){ ... }

我还建议删除HttpServletRequest参数并简单地添加您想要添加到模型中的属性。我可能会将该方法重写为类似以下内容的方法（也不确定为什么你仍然有该方法HttpSession？）。

@RequestMapping(value="unit/unitAdd.do", method=RequestMethod.POST)
public final String saveUnitAdd(@Valid @ModelAttribute("pmiUnitObject) PmiUnit pmiUnit, BindingResult bindingResult, Model model, HttpSession session){
    logger.info("saveAddUnit called!");
    boolean exists = unitService.isAlreadyExists("pmi_units", "uni_unit_name_pk",pmiUnit.getUniUnitNamePk());
    if (exists) {
        //exists and without state DEL, return exists error
        logger.info("Unit Name_PK exists");
        if(!unitService.isExistsAndDeleted("pmi_units", "uni_unit_name_pk",pmiUnit.getUniUnitNamePk())) {
            System.out.println("exists and not deleted");
            bindingResult.rejectValue("uniUnitNamePk", "pmi.validator.constraints.unique");}
            //exists but with state DEL, update this row
        }
    }

    if (!bindingResult.hasErrors() ) {
        unitService.updateDeletedUnit(pmiUnit);
        mainService.getDefaultPmiUnit(pmiUnit, model);
        model.addAttribute("fromAddUnit", "true");
        model.addAttribute("addResult", "true");
        return "accessControl1/unit/unitManage";
    } else {
        return "accessControl1/unit/unitAdd";
    }

}