Question

我将一个列表发送到我的jsp页面，该页面为用户提供选择。这部分做得很好。但是当请求被发送回控制器时为空。我将在控制器中通过@ModelAttribute获取请求，但该对象为null。 Jsp和控制器如下：

<form action="deleteAuthorExecution" method="post">
  Select Author: <select name="author">
<option value="all" label="All Authors">All Authors</option>
    <c:forEach var="author" items="${authorList}">
        <option value="${author}">${author}</option>
    </c:forEach>
</select> 
<input type="submit" value="submit"/>
</form>

@RequestMapping(value="/deleteAuthorExecution", method = RequestMethod.POST)
protected ModelAndView deleteAuthorExecution(@ModelAttribute Author author) throws Exception {

    authorService.delAuthor(author.getAuthorId());
    ModelAndView model = new ModelAndView("adminFunctionsPage");
    model.addObject("successMsg", "Your request has been processed Successfully.");
    return model;
}

作者对象变为空。任何人都可以给我一个提示我代码中的问题是什么？

Answer 1

我建议您不要发送整个作者对象，也可以传递authorId

<form action="deleteAuthorExecution" method="post">
  Select Author: <select name="author">
<option value="0" label="All Authors">All Authors</option>
    <c:forEach var="author" items="${authorList}">
        <option value="${author.authorId}">${author.authorName}</option>
    </c:forEach>
</select> 
<input type="submit" value="submit"/>
</form>

@RequestMapping(value="/deleteAuthorExecution", method = RequestMethod.POST)
protected ModelAndView deleteAuthorExecution(@RequestParam Integer authorId) throws Exception {

    if(authorId == 0){
       //user selected all, so delete all the authors   
    }
    authorService.delAuthor(authorId);
    ModelAndView model = new ModelAndView("adminFunctionsPage");
    model.addObject("successMsg", "Your request has been processed Successfully.");
    return model;
}

希望这有帮助

当我在spring MVC中向控制器发送请求时，为什么我变为null？

1 个答案: