Spring Ajax列表返回但对象为空

Question

I am building something like a locker management system and the lockers have an update history. I want use Ajax to return a list of of this history up to X entries in the list. Whenever I return List<LockerHistoryEntity> or Iterable<LockerHistoryEntity> , the amount of objects is returned, but all the objects are empty.

Example of the problem

Ajax call (called upon with getHistory(100) in this case):

function getHistory(limit) {
    var data = {};
    data["limit"] = limit;

    $.ajax({
        type: "POST",
        contentType: "application/json",
        url: "/gethistory",
        data: JSON.stringify(data),
        dataType: 'json',
        timeout: 100000,
        success : function(data) {
            fillTable(data);
            console.log(data);
            console.log(data.result);
        },
        error : function(e) {
            //error
        }
    });
}

@RestController

@JsonView(Views.Public.class)
    @RequestMapping(value = "/gethistory", method = RequestMethod.POST, produces="application/json")
    @ResponseBody
    public Iterable<LockerHistoryEntity> getHistory(@RequestBody HistoryLimit limit) {
        Iterable<LockerHistoryEntity> lockerHistory;

        if (limit.getLimit() >= 0) {
            lockerHistory = history.findAllLimit(limit.getLimit());
        } else {
            lockerHistory = history.findAll();
        }

        return lockerHistory;
    }

When using a for loop to print out lockerHistory the data is all displayed correctly.

Sadly, I couldn't find any topic about this exact problem, hence this post.

Answer 1

You need to convert the object into JSON form before sending the response to AJAX. See this link: http://howtodoinjava.com/jackson/jackson-examples-convert-java-object-to-from-json/