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需求，要求批量新增或者改动一个List，在Spring MVC中是不支持以下代码的写法
代码语言：javascript复制 @RequestMapping(value = "/update", method = RequestMethod.POST)
public String update(List<ProductCollocation> productCollocations ,HttpServletRequest request, RedirectAttributes redirectAttributes) {
for (ProductCollocation productCollocation : productCollocations) {
productCollocation.setModifyDate(DateUtil.getDate());
productCollocationService.update(productCollocation, "create_date","product","collocation","description");
}
addFlashMessage(redirectAttributes, SUCCESS_MESSAGE);
return "redirect:list.jhtml";
}会抛出异常
代码语言：javascript复制nested exception is org.springframework.beans.BeanInstantiationException: Could not instantiate bean class [java.util.List]: 是否事实上也非常easy，Spring MVC 须要支持Form表单对象的方式映射，使用get set器来填充对象。
新增一个Form
代码语言：javascript复制public class ProductCollocationForm {
List<ProductCollocation> productCollocations;
/**
* @return the productCollocations
*/
public List<ProductCollocation> getProductCollocations() {
return productCollocations;
}
/**
* @param productCollocations the productCollocations to set
*/
public void setProductCollocations(List<ProductCollocation> productCollocations) {
this.productCollocations = productCollocations;
}
}再使用Form来set对象
代码语言：javascript复制 @RequestMapping(value = "/update", method = RequestMethod.POST)
public String update(ProductCollocationForm productCollocationForm ,HttpServletRequest request, RedirectAttributes redirectAttributes) {
for (ProductCollocation productCollocation : productCollocationForm.getProductCollocations()) {
productCollocation.setModifyDate(DateUtil.getDate());
productCollocationService.update(productCollocation, "create_date","product","collocation","description");
}
addFlashMessage(redirectAttributes, SUCCESS_MESSAGE);
return "redirect:list.jhtml";
}前台就能够使用索引的方式对后台对象设置值了
代码语言：javascript复制<td>
<input type="text" name="productCollocations[${productCollocation_index}].displayName" class="text" maxlength="200" style="width:100px" value="${productCollocation.displayName}"/>
<input type="hidden" name="productCollocations[${productCollocation_index}].id" class="text" maxlength="200" value="${productCollocation.id}"/>
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