下拉框 - 从Spring MVC模型/上下文到使用freemarker形成 [英] Dropdown box - from Spring MVC model / context to form using freemarker

问题描述

这应该是非常基本的，但我在网上找不到任何关于它的东西，只是我看起来不能装在一起的点点滴滴..

<我们正在使用带有freemarker的Spring MVC。现在我想在页面中添加一个表单，允许我从预定义列表中选择一个值（需要在后端访问数据库）。

我的控制器：

  @RequestMapping（value =/ {id}，method = RequestMethod.GET）
 public ModelAndView get（@PathVariable Integer id）{
 
 // stuff .. 
 ModelAndView mav = new ModelAndView（）; 
 
 mav.addObject（targetObject，new TargetObject（））; 
 mav.addObject（options，Arrays.asList（a，b，c））; 
 mav.setViewName（someview）; 
 
返回mav; 
} 
  

我发现freemarkers spring支持 spring.ftl 似乎我应该使用< @ spring.formSingleSelect> 我试过这样：

someView.ftl：

 < #import../spring.ftl 作为春天/> 
 
< form action =somePathmethod =POST> 
< @ spring.formSingleSelecttargetObject.type，options，/> 
< input type =submitvalue =submit/> 
< / form> 
  

因此targetObject.type由宏看起来自动绑定。

但是如何让我的选项进入freemarker seequence以便宏可以创建选项？

现在我得到：

 预期的收集或序列。在spring.ftl的第227行第20行，将选项评估为freemarker.template.SimpleScalar。 
有问题的说明：
 ---------- 
 ==>将选项列为值[在第227行，spring.ftl第13列]用户指令spring.formSingleSelect中的
 [在第53行，productBase / show.ftl第9列] 
 ----- ----- 
  

我也试过：

 < @ spring.bind$ {options}/> 
  

以及更多内容但没有成功：

  freemarker.core.NonStringException：someView.ftl 
第48行第18行出错在这里期待字符串，日期或数字，表达式选项是freemarker .template.SimpleSequence 
  

感谢您的帮助！

解决方案

经过多次改写和重新思考后，我终于找到了解决方案：

第一次

我需要明确保留我的选择

第二

这些选项需要初始化为String列表，并由Spring MVC提供给页面：

  public ModelAndView get（）{
 
 // ... ... 
 ModelAndView mav = new ModelAndView（）; 
 List< String> options = Arrays.asList（getOptionsFromDatabaseAndConvertToStringList（））; 
 mav.addObject（options，options）; 
 mav.setViewName（someview）; 
 
返回mav; 
} 
  

第三

选项现在需要绑定在freemarker模板中，然后可以像任何其他freemarker变量一样进行访问（即否引号）：

 < @ spring.bindoptions/> 
 
< form action =whatevermethod =POST> 
< @ spring.formSingleSelecttargetBean.choice，options，/> 
< input type =submitvalue =submit/> 
< / form> 
  

This should be very basic but I can't find anything about it in the web, just bits and pieces that I don't seem able to fit together..

We're using Spring MVC with freemarker. Now I want to add a form to my page that allows me to select a value from a predefined list (requires database access in the backend).

My controller:

@RequestMapping(value = "/{id}", method = RequestMethod.GET)
public ModelAndView get(@PathVariable Integer id) {

    // stuff..
    ModelAndView mav = new ModelAndView();

    mav.addObject("targetObject", new TargetObject());
    mav.addObject("options", Arrays.asList("a", "b", "c"));
    mav.setViewName("someview");

    return mav;
}

I found freemarkers spring support spring.ftl and it seems I should use <@spring.formSingleSelect> which I've tried like this:

someView.ftl:

<#import "../spring.ftl" as spring />

<form action="somePath" method="POST">
    <@spring.formSingleSelect "targetObject.type", "options", " " />
    <input type="submit" value="submit"/>
</form>

So targetObject.type is bound automatically by the macro it seems.

But how do I get my options into a freemarker seequence so that the macro can create the options?

Right now I get:

Expected collection or sequence. options evaluated instead to freemarker.template.SimpleScalar on line 227, column 20 in spring.ftl.
The problematic instruction:
----------
==> list options as value [on line 227, column 13 in spring.ftl]
 in user-directive spring.formSingleSelect [on line 53, column 9 in productBase/show.ftl]
----------

I also tried:

<@spring.bind "${options}" />

and more things along those lines but with no success:

freemarker.core.NonStringException: Error on line 48, column 18 in someView.ftl
Expecting a string, date or number here, Expression options is instead a freemarker.template.SimpleSequence

Thank's for any help!

解决方案

After much rephrasing and rethinking I finally discovered the solution:

First

I need to have a bean hold my choice obviously

Second

The options need to be initialized as a String list and provided by Spring MVC to the page:

public ModelAndView get() {

    // ...
    ModelAndView mav = new ModelAndView();
    List<String> options = Arrays.asList(getOptionsFromDatabaseAndConvertToStringList());
    mav.addObject("options",options );
    mav.setViewName("someview");

    return mav;
}

Third

options now need to be bound in the freemarker template and can then be accessed like any other freemarker variable (i.e. NO quotation marks):

<@spring.bind "options" />

<form action="whatever" method="POST">
    <@spring.formSingleSelect "targetBean.choice", options, " " />
    <input type="submit" value="submit"/>
</form>

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