jQuery上传文件

页面：

<div class="container">
  <label>请输入标题:</label>
  <input type="text" placeholder="请输入" id="title" autocomplete="off">
  <label>请输入您的昵称:</label>
  <input type="text" placeholder="请输入" id="name" autocomplete="off">
  <label>附件:</label>
  <input id="file" type="file" value="" placeholder="附件">
  <input id="send" type="button" value="提交">
</div>

JS：

$("#send").click(function () {
        //创建表单
        var formData = new FormData();
        var title = $("#title").val();
        var name = $("#name").val();
        var file = $("#file")[0].files[0];
        //填充数据
        formData.append("title",title);
        formData.append("name",name);
        formData.append("file",file);
        
        $.ajax({
            type: "POST",
            url: "/mailtool/mail/send",
            //data: msg="+msg+"&title="+title+"&name="+name+"&file="+file,
            data: formData,
            contentType: false,
            processData: false,
            mimeType:"multipart/form-data",
            success: function(data){
                if(data == "success"){
                    alert("发送成功");
                }else{
                    alert(data);
                }
            }
        });
    })

后台：

@RestController
@RequestMapping("/mail")
public class Send {
    @PostMapping(value = "/send",produces="text/html;charset=utf-8")
    @ResponseBody
    public String send(@RequestParam(value = "file",required = false) MultipartFile file,@RequestParam("title") String title,@RequestParam("name") String name){
　　　　//todo
　　}
}