我正在编写一个websocket客户端,我希望以json字符串的形式接收消息.为此,我需要登录.如果登录不正确,我会发送一个json字符串,但没有成功.
{"action":"login","args":["nosuccess"]}
在客户机上,我用这个来获取字符串:
WebSocket socket = new WebSocket("ws://localhost:2555/api");
socket.onmessage = function(evt) {
console.log(evt.data);
console.log(typeof(evt.data));
onMessage(evt);
}
function onMessage(evt) {
var data = JSON.parse(evt.data);
var action = data.action;
var args = data.args;
console.log(data);
console.log(typeof(data));
console.log(action);
console.log(args);
但是数据类型是字符串. 但是为什么呢?
evt.数据返回:
"{\"action\":\"login\",\"args\":[\"nosuccess\"]}"
数据返回:
{"action":"login","args":["nosuccess"]}
The WebSocket server is a jetty Server which sends a string and a string array in json parsed in json with gson.toJson(class) Gson by Google. The Class is a class containing String action and String array args.
完整的websocket源代码.js:
var socket;
function openWebsocket(adress) {
socket = new WebSocket(adress);
socket.onopen = function(evt) {
console.log("Socket opened [" + adress + "]");
};
socket.onclose = function(evt) {
loadPage("login.html");
console.log("Socket closed [" + evt.code + "]");
}
socket.onmessage = function(evt) {
onMessage(evt);
}
socket.onerror = function(evt) {
console.log("Socket couldn't connect [" + evt.message + "]");
showMessage("fa-exclamation-circle", "Socket couldn't be established!", 1000);
}
}
function onMessage(evt) {
var data = JSON.parse(evt.data);
var action = data.action;
var args = data.args;
console.log(data);
console.log(typeof(data));
console.log(action);
console.log(args);
$(".card-container h3").html(data);
if(action == "login") {
if(args[0] == "success") {
loadPage("dashboard.htm");
currentpage = "dashboard.htm";
showMessage("fa-check", "Du wurdest erfolgreich eingeloggt", 2000);
} else if(args[0] == "nosuccess") {
loadPage("login.html");
currentpage = "login.html";
showMessage("fa-exclamation-circle", "Falscher Benutzername oder falsches Passwort", 2000);
} else if(args[0] == "unauthenticated") {
loadPage("login.html");
currentpage = "login.html";
showMessage("fa-exclamation-circle", "Login failure: not authenticated", 2000);
}
}
}
function sendMessage(json) {
$(".card-container h3").html(JSON.stringify(json));
console.log(JSON.stringify(json));
socket.send(JSON.stringify(json));
}
If I change this line:
var data = JSON.parse(evt.data);
对此,请执行以下操作:
var data = JSON.parse("{\"action\":\"login\",\"args\":[\"nosuccess\"]}");
Then it is a json object, but when I use evt.data then it is a string. If I change the line 对此,请执行以下操作:
var data = JSON.parse(JSON.parse(evt.data));
Then it works, but why, normally it should do it with only one JSON.parse, should it?