使用nashorn在Java 8中获取正确的JSON文字 [英] Get a proper JSON literal in Java 8 using nashorn

问题描述

我有一条消息要通过套接字发送，它是代表json的字符串:

I have a message that's to be sent over a socket, a string that represents a json:

String message = "{\"sql\": \"{0}\"}";

我使用MessageFormatter来输入来自用户的实际消息，并将其发送到服务器.

I use MessageFormatter to put in the actual message from the user, and send it to the server.

但是，这必须是服务器可以理解的正确JSON字符串.

However, this needs to be a proper JSON string for the server to understand.

在尝试了手动转义之后，意识到SQL消息可以包含嵌套的引号和其他内容，我知道我想使用适当的JSON工具来确保字符串是JSON正确的.

After dabbling with manual escaping, realizing the SQL message can have nested quotes and whatnot, I understand I want to use a proper JSON tool to make sure the string is json-correct.

我希望使用nashorn保持代码的香草味，并避免在罐子里放行李.

I wish to use nashorn to keep the code vanilla and avoid baggage in the jar.

纳斯霍恩(Nashorn)似乎很胜任并且很适合完成这项任务，但是我正在随手拿起它，现在还不确定该怎么做.

Nashorn seems quite capable and fit for the task, but I'm picking it up as I go, and I'm not sure what to do at this point.

我尝试了此答案中的代码:

ScriptEngine engine = new ScriptEngineManager().getEngineByName("nashorn");
ScriptObjectMirror json = (ScriptObjectMirror) engine.eval("JSON");
message = (String) json.callMember("stringify", json.callMember("parse", message));

但是，这只是验证我的字符串，我希望nashorn实际将其转义为正确的形式.

However, this merely validates my string, I wish nashorn to actually escape it to a proper form.

• 我知道杰克逊.
• 我知道其他JSON库.

任何见识将不胜感激.

推荐答案

我发现的方法是通过Bindings将用户字符串作为变量传递给引擎.

The way I found is to pass the user string as a variable to the engine via Bindings.

然后您可以通过engine.eval("JSON.stringify()")进行字符串化:

Then you can stringify via engine.eval("JSON.stringify()"):

ScriptEngine engine = new ScriptEngineManager().getEngineByName("nashorn");
Bindings bindings = engine.getContext().getBindings(ScriptContext.GLOBAL_SCOPE);
bindings.put("sql_from_user", sql);
String proper_json_message = (String) engine.eval("JSON.stringify({sql : sql_from_user})");

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