我正在尝试将 json 字符串发送到服务器，然后将其存储在数据库中
以下是我的代码:
$.ajax({
url: 'JsonProcessor.do',
type: 'post',
dataType: 'json',
data: {
loadProds: 1,
test: JSON.stringify(StateObject)
},
success: function (data)
{
console.log("worked");
},
error: function (data) {
alert('failed');
}
});
Servlet:
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String json = request.getParameter("test");
System.out.println("json is: " + json);
Connection con = null;
ResultSet rs = null;
try {
con = OracleDBConnection.getConnection();
String query = "insert into JJS (JSON_INFO) values(?)";
PreparedStatement pst = con.prepareStatement(query);
pst.setString(1, json);
rs = pst.executeQuery();
if (rs.next()) {
System.out.println("sucess");
} else {
System.out.println("failed");
}
} catch (Exception e) {
e.printStackTrace();
System.out.println("DB releated exception");
}
但是，当我尝试打印 request.getparameter(json) 时，它返回 null。
这是我要发送的 json:
{
"cells": [
{
"type": "basic.Rect",
"position": {
"x": -2,
"y": 33
},
"size": {
"width": 71,
"height": 625
},
"angle": 0,
"isInteractive": false,
"id": "e276b993-af5e-4e32-9879-fc3d817c0811",
"z": 1,
"attrs": {
"rect": {
"fill": "#EEEEEE",
"stroke": "#008B8B",
"stroke-width": 2
},
".": {
"magnet": false
}
}
},
{
"type": "basic.Rect",
"position": {
"x": 10,
"y": 50
},
"size": {
"width": 51,
"height": 41
},
"angle": 0,
"isInteractive": false,
"id": "f8826904-678c-4857-ad46-f86e69d1db32",
"z": 2,
"attrs": {
"rect": {
"fill": "#D6F2FC",
"stroke": "#7E7E7E"
},
".": {
"magnet": false
}
}
},
{
"type": "basic.Circle",
"size": {
"width": 53,
"height": 53
},
"position": {
"x": 8,
"y": 130
},
"angle": 0,
"isInteractive": false,
"id": "e4ee7b74-3c06-4e1e-8ce7-8baf6743c27c",
"z": 3,
"attrs": {
".": {
"magnet": false
},
"circle1": {
"fill": "white",
"stroke-width": 2,
"stroke": "green"
}
}
},
{
"type": "basic.Circle",
"size": {
"width": 53,
"height": 53
},
"position": {
"x": 8,
"y": 225
},
"angle": 0,
"isInteractive": false,
"id": "04d4a40b-f99b-4c16-89a9-7d072e30c4ad",
"z": 4,
"attrs": {
".": {
"magnet": false
},
"circle2": {
"fill": "white",
"stroke": "green"
}
}
},
{
"type": "basic.Circle",
"size": {
"width": 53,
"height": 53
},
"position": {
"x": 8,
"y": 320
},
"angle": 0,
"isInteractive": false,
"id": "97a01219-b7e2-4a52-9248-eb41dc7443b4",
"z": 5,
"attrs": {
".": {
"magnet": false
},
"circle3": {
"fill": "white",
"stroke": "green"
}
}
},
{
"type": "basic.Rect",
"position": {
"x": 10,
"y": 420
},
"size": {
"width": 51,
"height": 41
},
"angle": 0,
"isInteractive": false,
"id": "ed74bfd7-c7e2-4f68-85c3-0f1865243d3e",
"z": 6,
"attrs": {
".": {
"magnet": false
},
"rectGroup0": {
"fill": "white",
"stroke": "#7E7E7E"
}
}
},
{
"type": "basic.Rect",
"position": {
"x": 35,
"y": 505
},
"size": {
"width": 45,
"height": 45
},
"angle": 0,
"isInteractive": false,
"id": "008c90ea-2598-4761-8775-fc3601c8935d",
"z": 7,
"attrs": {
"rect": {
"fill": "#FFED6B",
"stroke": "#DBCB62",
"width": 1,
"height": 1,
"stroke-width": 1,
"transform": "rotate(45)"
},
".": {
"magnet": false
}
}
}
]
}
最佳答案
您的代码存在多个问题:
发送时，jquery 已经为您进行了字符串化，因此您自己调用它时，实际上是在发送的 json 中创建一个字符串属性(您可以通过使用浏览器查看发送的数据来轻松检查这一点)
$.ajax({
url: 'JsonProcessor.do',
type: 'post',
dataType: 'json',
data: {
loadProds: 1,
test: JSON.stringify(StateObject)
},
...
实际上会创建一个如下所示的 http 请求正文:
{
loadProds: 1,
test: "{\"state\": .... "
}
所以只需写:
$.ajax({
url: 'JsonProcessor.do',
type: 'post',
dataType: 'json',
data: {
loadProds: 1,
test: StateObject
},
...
你会在这方面做得很好。
对于服务器部分，您实际上是在寻找名为“test”的请求参数。但这不是发送的内容。相反，您会得到一个包含 json 的“主体”。使用 dataType:json 时根本没有标准请求参数。
所以在你的情况下是
String json = IOUtils.toString(request.getInputStream());
也不是你在那里检索的 json 包含“loadProps: 1”... 然后，您可能希望将字符串转换为对象(使用 jackson )，以便您可以使用它。
关于java - 使用ajax请求发送时json值返回null，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/31784440/