Spring MVC 不支持请求方法“GET”

Question

我在控制器中有以下代码

  private static final String CJOB_MODEL    = "cJobNms";

  @RequestMapping(value = MAIN_VIEW, method = RequestMethod.POST)
  public String showTestXsd(//@ModelAttribute(FORM_MODEL) TestXsdForm xsdForm,
            //@ModelAttribute(MODEL) @Valid
            //TestXsdTable testXsdTable,
            @RequestParam String selected,
            Model model) throws DataException {

        String cJobNm =null;
        List<String> cJobNmList = null;
        System.out.println("selected:"+ selected);
        String xsdView = testXsdService.getXsdString();
        cJobNmList = testXsdService.getCJobNm();
        Set<String> cJobNmSet = new HashSet<String>(cJobNmList);
        TestXsdForm xsdForm = new TestXsdForm();
        model.addAttribute("xsdView", xsdView);
        model.addAttribute("xsdFormModel", xsdForm);
        model.addAttribute(CJOB_MODEL, cJobNmSet);
        xsdForm.setXsdString(xsdView);

        return MAIN_VIEW;
    }

以及我的jsp中的以下代码。

<form:form modelAttribute="testXsdTable" name="xsdForm" action="/xsdtest/testXsdTables"
                        id="xsdForm" method="POST" class="form"
                                            enctype="multipart/form-data" >


            <tr>
             <td>
              <label for="cJobs" class="fieldlabel">Jobs:</label>
               <select id="cJobs" name="cJobs" >
                <option value="${selected}" selected>${selected}</option>
                <c:forEach items="${cJobNms}" var="table">
                    <c:if test="${table != selected}">
                            <option value="${table}">${table}</option>
                        </c:if>
                 </c:forEach>
               </select>
            </td>
            </tr>
            <pre>
               <c:out value="${xsdForm.xsdString}"/>
            </pre>
<div class="confirmbuttons">
    <a href="#"class="button positive" id="saveXsdButton" onclick="saveTestXsd();">
        <span class="confirm">Save</span>
    </a>
</div>

当用户从 cJobNms 列表中选择一个选项时，所选值应显示在控制器方法 showTestXsd 中。请让我知道我做错了什么。

目前我收到一条消息：不支持请求方法“GET”

 @RequestMapping(value = SAVE_VIEW, method = RequestMethod.POST)
public String saveTestXsd( @ModelAttribute(MODEL) @Valid
                            TestXsdTable testXsdTable,
                            final BindingResult result,
                            final Principal principal,
                            Model model) throws DataException {

    boolean isNew = true;
    System.out.println("entering saveTestXsd in controller");
    Map<String,Object> modelMap = model.asMap();
    String xsdView = (String)modelMap.get("xsdView");
    System.out.println("xsdView:::"+ xsdView);
    if(testXsdTable!= null){
         System.out.println("xsdView(testXsdForm):::"+ testXsdTable.getXsdView());
    }


    // Check for validation errors
    if (result.hasErrors()) {
        return SAVE_VIEW;
    }

    // Get the user information
    User loggedInUser = (User) ((Authentication) principal)
                        .getPrincipal();

    return SAVE_VIEW;
}

Answer 1

我将开始回答并在详细信息可用时添加。对于您当前的错误

org.springframework.web.bind.MissingServletRequestParameterException: Required String parameter 'selected' is not present

这是因为当你有类似的东西时

@RequestParam String selected,

而@RequestParam没有value属性集，Spring会使用参数名去寻找请求参数进行绑定。在您的表单中，您显然没有名为selected 的参数。你想要的是在

<select id="cJobs" name="cJobs" >

所以把你的@RequestParam改成

@RequestParam(value = "cJobs") String selected

匹配select输入元素的name属性。

Answer 2

替换

@RequestMapping(value = MAIN_VIEW, method = RequestMethod.POST)

与

@RequestMapping(value = MAIN_VIEW, method = RequestMethod.GET)

您还应该考虑更改表单 POST 方法。您的用例更多的是 Get 而不是 POST

Answer 3

使用下一个代码

@RequestMapping(value = MAIN_VIEW, method = RequestMethod.GET)
//if you want to use both ( post and get ) remove Request Method annotation

//@RequestMapping(value = MAIN_VIEW)
@RequestParam(value="cJobs", required = false) String selected; 
//use this to handle an optional parameter

Answer 4

您只需更改您在代码中使用的@RequestParam，例如

@RequestParam("studentName") String name

将上面的代码行替换为

@RequestParam(value="studentName") String name

你的问题一定会解决的。