如何使用 Json.simple 解析 Java 中的 JSONArray？
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How do I parse a JSONArray in Java with Json.simple?
提问by Jibi
I am trying to read a JSON file like this:
我正在尝试读取这样的 JSON 文件：
{
"presentationName" : "Here some text",
"presentationAutor" : "Here some text",
"presentationSlides" : [
{
"title" : "Here some text.",
"paragraphs" : [
{
"value" : "Here some text."
},
{
"value" : "Here some text."
}
]
},
{
"title" : "Here some text.",
"paragraphs" : [
{
"value" : "Here some text.",
"image" : "Here some text."
},
{
"value" : "Here some text."
},
{
"value" : "Here some text."
}
]
}
]
}
It's for a school exercise. I chose to try and use JSON.simple (from GoogleCode), but I am open to another JSON library. I heard about Hymanson and Gson: Are they better than JSON.simple?
这是一个学校练习。我选择尝试使用 JSON.simple（来自 GoogleCode），但我对另一个 JSON 库持开放态度。我听说过 Hymanson 和 Gson：他们比 JSON.simple 更好吗？
Here is my current Java code:
这是我当前的 Java 代码：
Object obj = parser.parse(new FileReader( "file.json" ));
JSONObject jsonObject = (JSONObject) obj;
// First I take the global data
String name = (String) jsonObject.get("presentationName");
String autor = (String) jsonObject.get("presentationAutor");
System.out.println("Name: "+name);
System.out.println("Autor: "+autor);
// Now we try to take the data from "presentationSlides" array
JSONArray slideContent = (JSONArray) jsonObject.get("presentationSlides");
Iterator i = slideContent.iterator();
while (i.hasNext()) {
System.out.println(i.next());
// Here I try to take the title element from my slide but it doesn't work!
String title = (String) jsonObject.get("title");
System.out.println(title);
}
I checked out a lot of examples (some on Stack!) but I never found the solution to my problem.
我查看了很多示例（一些在 Stack 上！）但我从未找到解决我的问题的方法。
Maybe we can't do this with JSON.simple? What do you recommend?
也许我们不能用 JSON.simple 做到这一点？你有什么建议吗？
采纳答案by Russell Zahniser
You never assign a new value to jsonObject, so inside the loop it still refers to the full data object. I think you want something like:
您永远不会为 分配新值jsonObject，因此在循环内它仍然引用完整的数据对象。我想你想要这样的东西：
JSONObject slide = i.next();
String title = (String)slide.get("title");
回答by Jibi
It's working! Thx Russell. I will finish my exercice and try GSON to see the difference.
它正在工作！谢谢罗素。我将完成我的练习并尝试 GSON 以查看差异。
New code here:
新代码在这里：
JSONArray slideContent = (JSONArray) jsonObject.get("presentationSlides");
Iterator i = slideContent.iterator();
while (i.hasNext()) {
JSONObject slide = (JSONObject) i.next();
String title = (String)slide.get("title");
System.out.println(title);
}
