Spring MVC中所需的字符串参数不存在错误

Question

我尝试在Spring MVC中对我的控制器进行AJAX查询。

我的操作代码是：

@RequestMapping(value = "events/add", method = RequestMethod.POST)
public void addEvent(@RequestParam(value = "start_date") String start_date, @RequestParam(value = "end_date") String end_date, @RequestParam(value = "text") String text, @RequestParam(value = "userId") String userId){
    //some code    
}

我的Ajax查询是：

$.ajax({
        type: "POST",
        url:url,
        contentType: "application/json",
        data:     {
                start_date:   scheduler.getEvent(id).start_date,
                end_date:  scheduler.getEvent(id).end_date,
                text: scheduler.getEvent(id).text,
                userId: userId
        },
        success:function(result){
         //here some code
        }
    });

但我有个错误：

必需的字符串参数“start_date”不存在

为什么？正如我所知，我像(@requestparam(value=“start_date”）String start_date一样呈现了它

public class EventData {
    public String end_date;
    public String start_date;
    public String text;
    public String userId;
    //Getters and setters
}

$.ajax({
    type: "POST",
    url:url,
    contentType: "application/json",
    // data: eventData,
    processData: false,
    data:    JSON.stringify({
        "start_date":   scheduler.getEventStartDate(id),
        "end_date":  scheduler.getEventEndDate(id),
        "text": scheduler.getEventText(id),
        "userId": "1"
    }),

和控制器操作：

@RequestMapping(value = "events/add", method = RequestMethod.POST)
public void addEvent(@RequestBody EventData eventData){    
}

JSON数据如下：

end_date: "2013-10-03T20:05:00.000Z"
start_date: "2013-10-03T20:00:00.000Z"
text: "gfsgsdgs"
userId: "1"

Answer 1

在服务器端，您希望您的请求参数作为查询字符串，但是在客户端，您发送一个json对象。要绑定json，您需要创建一个包含所有参数的类，并使用@RequestBody注释而不是@RequestParam。

@RequestMapping(value = "events/add", method = RequestMethod.POST)
public void addEvent(@RequestBody CommandBean commandBean){
    //some code
}

这里有一个更详细的解释。