Spring MVC中不存在必需的String参数错误

Question

我尝试在Spring MVC中向我的控制器发出一个AJAX查询.

我的行动代码是:

@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
        }
    });

但是我收到了一个错误:

必需的字符串参数''start_date不存在

为什么？据我所知,我提出了它(@RequestParam(value = "start_date") String start_date

UDP
现在我给404我的类来获取数据

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

我的js AJAX调用是:

$.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"
    }),

和控制器动作:

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

而JSON数据是:

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
}

这是一个更详细的解释.