javascript - Java 类接收 Ajax JSON post 作为 null

Question

我正在尝试使用ajax post方法将json数据发送到Java类。当我硬编码出一个 json 字符串时，我的 Java 对象接收它很好，但是当我尝试发送使用 JSON.stringify() 创建的 json 字符串时，我在 Controller 中得到所有空值...

这是流程，我有以下 html 表格:

<table class="table" id="internalUnsubmittedPartRequests">
    <thead>
        <tr>
            <th id="partID">partID</th>
            <th id="quantity">quantity</th>
            <th id="applicableModel">applicableModel</th>
            <th id="queueName">queueName</th>
            <th id="issueType">issueType</th>
            <th id="controlCode">controlCode</th>
            <th id="position">position</th>
            <th id="command">command</th>
            <th id="activationDate">activationDate</th>
            <th id="flushDate">flushDate</th>
        </tr>
    </thead>
    <tbody>
        <!-- Dynamically Generated via newRequest.js -->
    </tbody>
</table>

下面的 javascript 从该表中读取并使用 ajax 将其发送到我的 Controller :

$('#submit_set_btn').click(function(event) {
    var myRows = [];
    var $headers = $("th");
    var $rows = $("#internalUnsubmittedPartRequests tr").each(function(index) {
      $cells = $(this).find("td");
      myRows[index] = {};
      $cells.each(function(cellIndex) {
        myRows[index][$($headers[cellIndex]).html()] = $(this).html();
      });    
    });
    myRows.shift();
    var myObj = {};
    myObj.myrows = myRows;
    console.log(JSON.stringify(myObj));

    $.ajax({
        type : "POST",
        // contentType : "application/json; charset=utf-8",
        url : window.location,
        data : JSON.stringify(myObj),
        dataType : 'json',
        success : function(result) {
            //alert("success");
            console.log("success");
            console.log(result);
        },
        error : function(e) {
            //alert("fail");
            console.log("fail");
            console.log(e);
        }
    });
});

在 console.log(JSON.stringify(myObj)) 调用期间，以下内容将打印到控制台:

{"myrows":[{"partID":"data","quantity":"data","applicableModel":"data","queueName":"data","issueType":"data","controlCode":"data","position":"data","command":"data","activationDate":"data","flushDate":"data"}]}

这是代表我尝试创建的对象的 Java 类:

public class NewPartRequest
{
private String partID;
private String quantity;
private String applicableModel;
private String queueName;
private String issueType;
private String controlCode;
private String position;
private String command;
private String activationDate;
private String flushDate;

@Override
public String toString() {
    return getPartID() + " " + getQuantity() + " " + getApplicableModel() + " " + 
           getQueueName() + " " + getIssueType() + " " + getCommand() + " " + 
           getActivationDate() + " " + getFlushDate();
}


//Getters and Setters below this line

最后 Controller 类接收 JSON 数据并使用 toString 方法显示我们得到的内容:

@Controller
public class DistributionNewRequestController {

@RequestMapping(value = "/distribution/internal/unsubmitted/new-request", method = { RequestMethod.GET })
public String newRequest() {
    return "new-request";
}

@RequestMapping(value = "/distribution/internal/unsubmitted/new-request", method = {
        RequestMethod.POST }, produces = MediaType.APPLICATION_JSON_UTF8_VALUE)
public @ResponseBody String internalRequestPost(@RequestBody NewPartRequest newPartRequest) {

    System.out.println("The new part request toString method: ");
    System.out.println(newPartRequest.toString());

    String response = jsonify(newPartRequest);
    return response;

}

private String jsonify(NewPartRequest in) {
    Gson gson = new Gson();
    String out = gson.toJson(in);
    return out;
}

}

在 NewPartRequest newPartRequest 对象上调用 toString() 方法，并打印以下内容:

The new part request toString method: 
null null null null null null null null

我已经被这个问题困扰很长时间了，我不明白为什么我的所有属性的值都是空。

Answer 1

您需要更改 ajax 帖子，如下所示

data : JSON.stringify(myObj.myrows[0]),

或者您可以像这样更改后端代码

List<NewPartRequest>

然后像下面这样从ajax传递

data : JSON.stringify(myObj.myrows),

您实际上传递了一个对象列表，并期望后端 Controller 方法中只有一个对象。