在Servlet内检索从JSON发送为JSON的数据 [英] Retrieve the data sent as JSON from JavaScript, inside a servlet

问题描述

我在从Java servlet内的JavaScript检索以JSON形式发送的数据时有一个查询. 以下是我在做什么...

I have a query on retrieving data sent as JSON from a JavaScript, inside a Java servlet. Following is what I am doing...

这是JavaScript内向Servlet发出请求的代码的一部分

This is the part of the code inside JavaScript making a request to a servlet

type : "POST",
url: 'getInitialData',
datatype: 'json',
data : ({items :[{ name: "John", time: "2pm" },{name: "Sam", time: "1pm" }]}),
success: function(data) {
    try{
          ////Code to be handeled where response is recieved
       }catch(e){
        alert(e);
    }
}

在发出此请求时，我尝试检索从Servlet中的JavaScript发送的参数，但这样做时，我首先对如何从请求中检索数据感到困惑

On making this request I try to retrieve the parameters sent from JavaScript in a Servlet, but while doing so I was firstly confused on how to retrieve the dat from the request

我在servlet中使用了以下内容:

I used the following in my servlet:

注意::我的Servlet中的内容类型设置为: apllication/json

NOTE : the content Type in my Servlet is set to : apllication/json

 response.setContentType("application/json");

 request.getParameterMap();

上面显示的数据如下，但我无法弄清楚如何工作并获取实际数据

the above showed me the data as below, but I was not able figure out how to work and get the actual data

{items[1][name]=[Ljava.lang.String;@1930089, items[0][time]=[Ljava.lang.String;@860ba, items[1][time]=[Ljava.lang.String;@664ca, items[0][name]=[Ljava.lang.String;@1c334de}

而以下代码为我提供了预期为null的异常.

while the following code gave me Exception of null which was expected.

request.getParametervalues("items");

在我尝试过的其他请求中，其中request.getParameter(); request.getParameterNames();但徒劳...

Among the others i tried where request.getParameter(); request.getParameterNames(); but in vain...

我的方向错误吗?请指导我！ 请让我知道如何重新获得这些价值.

Am I in a wrong direction? Please guide me! Please let me know how to retieve these value.

感谢您阅读这篇冗长的文章...

Thank You for reading this long post...

Sangeet

推荐答案

请求参数映射是Map<String, String[]>，其中映射键是参数名称，映射值是参数值--HTTP允许在一个以上的值相同的名字.

The request parameter map is a Map<String, String[]> where the map key is the parameter name and map value are the parameter values --HTTP allows more than one value on the same name.

鉴于地图的打印输出，应该可以进行以下操作:

Given the printout of your map, the following should work:

String item0Name = request.getParameter("items[0][name]");
String item0Time = request.getParameter("items[0][time]");
String item1Name = request.getParameter("items[1][name]");
String item1Time = request.getParameter("items[1][time]");

如果您想获得更多动态效果，请使用以下命令:

If you want a bit more dynamics, use the following:

for (int i = 0; i < Integer.MAX_VALUE; i++) {
    String itemName = request.getParameter("items[" + i + "][name]");
    String itemTime = request.getParameter("items[" + i + "][time]");

    if (itemName == null) {
        break;
    }

    // Collect name and time in some bean and add to list yourself.
}

请注意，设置响应内容类型与收集请求参数无关.

Note that setting the response content type is irrelevant when it comes to gathering the request parameters.

这篇关于在Servlet内检索从JSON发送为JSON的数据的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！