java - 在 null 上找不到属性或字段“索引”
问题描述
我使用spring boot将文件上传到数据库并尝试将该文件显示到页面中,但出现错误。
错误:
原因:org.attoparser.ParseException:评估 SpringEL 表达式的异常:org.attoparser.MarkupParser.parseDocument(MarkupParser.java:393) 处的“itrStat.index”(模板:“view/user” - 第 110 行,第 69 列)~ [attoparser-2.0.5.RELEASE.jar:2.0.5.RELEASE] 在 org.attoparser.MarkupParser.parse(MarkupParser.java:257) ~[attoparser-2.0.5.RELEASE.jar:2.0.5.RELEASE]在 org.thymeleaf.templateparser.markup.AbstractMarkupTemplateParser.parse(AbstractMarkupTemplateParser.java:230) ~[thymeleaf-3.0.11.RELEASE.jar:3.0.11.RELEASE] ...省略了 48 个常用框架
用户.html
<body>
<div class="container-fluid">
<div class="row">
<div class="col-md-12">
<fieldset>
<legend>User Form</legend>
<div class="alert alert-success alert-dismissible" th:if="${success}">
<button type="button" class="close" data-dismiss="alert">×</button>
<strong th:if="${success}"></strong>
</div>
<div class="alert alert-danger alert-dismissible" th:if="${errormeassage}">
<button type="button" class="close" data-dismiss="alert">×</button>
<strong th:if="${errormeassage}"></strong>
</div>
<form action="#" th:action="@{${isAdd}?'/save':'/update'}" th:object="${user}" method="post" enctype="multipart/form-data">
<div class="form-group">
<input type="text" id="firstname" name="firstname" th:field="*{firstname}" placeholder="First Name" >
</div>
<div class="form-group">
<input type="text" id="lastname" name="lastname" th:field="*{lastname}" placeholder="Last Name" >
</div>
<div class="form-group">
<input type="text" id="email" name="email" th:field="*{email}" placeholder="Email ">
</div>
<div class="form-group">
<input type="text" id="phone" name="phone" th:field="*{phone}" placeholder="Phone number" >
</div>
<div class="form-group" style="margin-left: 110px;">
<input type="file" id="file" value="upload" name="file" th:field="*{file}" placeholder="Upload file " multiple="multiple">
</div>
<div class="form-group">
<span th:each="file,itrStat:${userFiles}" class="imagecontainer" th:id="'imageIndex'+${itrStat.index}">
<img alt="" src="@{'/images/'+${file.modifiedFileName}}" style="width: 80px;height: 80px;border-radius: 50%;margin-left: 10px;" class="image" th:if="${file.fileExtension!='pdf' and file.fileExtension!='xls' and file.fileExtension!='xlsx}" >
<img alt="" src="@{'/img/pdf.png'}" style="width: 80px;height: 80px;border-radius: 50%;margin-left: 10px;" class="image" th:if="${file.fileExtension =='pdf'}" >
<img alt="" src="@{'/img/excel.png'}" style="width: 80px;height: 80px;border-radius: 50%;margin-left: 10px;" class="image" th:if="${file.fileExtension =='xls' or file.fileExtension =='xlsx}">
</span>
<span class="overlay">
<a href="#" class="icon image-confirm-delete" title="image delete" th:attr="data-id=${itrStat.index}, data-name=${file.modifiedFileName}">
<i class="fa fa-trash" style="color: red;"></i>
</a>
</span>
</div>
<input type="hidden" th:field="*{remove}" th:id="remove">
<input type="hidden" th:field="*{id}" id="id">
<div class="form-group">
<button type="submit" class="btn btn-primary" th:text="${isAd}?'Save':'Update'"></button>
</div>
<hr>
</form>
</fieldset>
</div>
<div class="col-md-12">
<h2>ALl Users</h2>
<div style="margin-top: 20px;">
<table class="table table-striped table-bordered">
<thead>
<tr>
<th>First Name</th>
<th>Last Name</th>
<th>Email</th>
<th>Phone</th>
<th>Action</th>
</tr>
</thead>
<tbody>
<tr th:each="user:${users}">
<td th:text="${user.firstname}"></td>
<td th:text="${user.lastname}"></td>
<td th:text="${user.email}"></td>
<td th:text="${user.phone}"></td>
<td>
<a th:href="@{'/edituser/'+${user.id}}"><i class="fa fa-edit" style="font-size:48px;color:red"></i></a>
</td>
</tr>
</tbody>
</table>
</div>
</div>
</div>
</div>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.4.1/jquery.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.1.3/js/bootstrap.min.js"></script>
<script type="text/javascript">
$(function(){
var images[];
$('.image-confirm-delete').on('click',function(e){
e.preventDefault();
var id = $(this).data('id');
var name = $(this).data('name');
images.push(name);
${'#remove'}.val(images);
$('#imageIndex'+id).hide();
});
});
</script>
</body>
控制器类
@Controller
public class FileUploadController {
@Autowired
private UserService userService;
@RequestMapping("/")
public String users(Model model,@Valid User user,BindingResult bindingResult) {
List<User>listUser = userService.getAllUsers();
model.addAttribute("users",listUser);
model.addAttribute("user", new User());
model.addAttribute("userFiles", new ArrayList<UserFiles>());
model.addAttribute("isAdd", true);
return "view/user";
}
@PostMapping("/save")
public String saveUser(@ModelAttribute User user,RedirectAttributes redirectAttributes,Model model) {
User dbUser = userService.save(user);
if(dbUser!=null) {
model.addAttribute("success","user is successfully saved!!");
return "redirect:/";
}else {
model.addAttribute("errormeassage","user not saved,please try new one!!");
model.addAttribute("user",user);
return "view/user";
}
}
@GetMapping(value ="/edituser/{id}")
public String editUsers(@PathVariable Long id, Model model) {
User user= userService.findById(id);
//fetch file
List<UserFiles> files = userService.findFilesByUserId(id);
List<User>listUser = userService.getAllUsers();
model.addAttribute("users",listUser);
model.addAttribute("user", user);
model.addAttribute("userFiles",files);
model.addAttribute("isAdd", false);
return "view/user";
}
}
解决方案
我相信根据Thymeleaf 文档th:each
中定义的状态变量称为iterStat。
您能否尝试在您的代码中将“itrStat”替换为“iterStat”?
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