Java 不同的 JSON 数组响应
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Different JSON array response
提问by Mitja Rogl
I have problems parsing two different JSON responses.
我在解析两个不同的 JSON 响应时遇到问题。
1: This is the JSON response I get from a RESTful API:
1：这是我从 RESTful API 得到的 JSON 响应：
{
"gear": [
{
"idGear": "1",
"name": "Nosilec za kolesa",
"year": "2005",
"price": "777.0"
}, {
"idGear": "2",
"name": "Stresni nosilci",
"year": "1983",
"price": "40.0"
}
]
}
2: This response I get from my testing client. I was added some values to the list and then I used gson.toJsonfor testing output.
2：我从我的测试客户那里得到的这个回应。我在列表中添加了一些值，然后用于gson.toJson测试输出。
[
{
"idGear": "1",
"name": "lala",
"year": 2000,
"price": 15.0
}, {
"idGear": "2",
"name": "lala2",
"year": 2000,
"price": 125.0
}
]
They are both valid, but the second one was successfully deserialize to object like this:
它们都是有效的，但第二个成功地反序列化为这样的对象：
Type listType = new TypeToken<List<Gear>>() {}.getType();
List<Gear> gears= (List<Gear>) gson.fromJson(json, listType);
With the first one, I was trying to deserialize the same way but I get error.
对于第一个，我试图以相同的方式反序列化，但出现错误。
EDIT
编辑
API Method:
API方法：
@GET
@Produces(MediaType.APPLICATION_JSON)
public List<Gear> getGear() {
List<Gear> gears = gearDAO.getGears();
if (!gears.isEmpty()) {
return gears;
} else
throw new RuntimeException("No gears");
}
CLIENT serialization code:
客户端序列化代码：
List<Gear> list = new ArrayList<Gear>();
Gear o = new Gear();
o.setPrice(15);
o.setYear(2000);
o.setName("asds");
Type listTypes = new TypeToken<List<Gear>>() {}.getType();
gson.toJson(list, listTypes);
采纳答案by MikO
The JSON responses are different!
JSON 响应是不同的！
The first one is an object, surrounded by
{ }, which contains a field"gear"that is in turn a list of objects, surrounded by[ ].The second one is directly a list of objects, because it's surrounded by
[ ]. Namely, the whole 2nd response is equivalent to the field in the 1st response.
第一个是一个对象，由 包围
{ }，其中包含一个字段"gear"，该字段又是一个对象列表，由 包围[ ]。第二个是直接的对象列表，因为它被
[ ]. 即，整个第二个响应相当于第一个响应中的字段。
So, obviously they can't be parsed in the same way...
所以，显然它们不能以同样的方式解析......
The 2nd one is being parsed correctly because you are using a Listand it is a list. But for the 1st one you need another class that contains a field that contains in turn a list... That is, you just need to create a class structure that represents your JSON responses...
第二个正在被正确解析，因为您使用的是 aList并且它是一个列表。但是对于第一个，您需要另一个包含一个字段的类，该字段又包含一个列表...也就是说，您只需要创建一个表示您的 JSON 响应的类结构...
public class Response {
private List<Gear> gears;
//getters & setters
}
Now you can parse your 1st response with:
现在您可以解析您的第一个响应：
Gson gson = new Gson();
Response response = gson.fromJson(json, Response .class);
List<Gear> gears = response.getGears();
I suggest you to take a brief look at json.orgin order to understand JSON syntax, which is pretty simple... Basically these are the possible JSON elements:
我建议你简单地看一下json.org以了解 JSON 语法，这非常简单......基本上这些是可能的 JSON 元素：
object
{}
{ members }
members
pair
pair , members
pair
string : value
array
[]
[ elements ]
elements
value
value , elements
value
string
number
object
array
true
false
null
