如何将JSON解析为字符串列表？

Question

我有一个json文件。

{
    "data" : [
        "my/path/old",
        "my/path/new"
    ]
}

我需要将它转换为String的ArrayList。如何使用Jackson库？

Gson gson = new Gson();        
JsonReader reader = new JsonReader(new InputStreamReader(FileReader.class.getResourceAsStream(file)));

List<String> list = (ArrayList) gson.fromJson(reader, ArrayList.class);

for (String s : list) {
    System.out.println(s);
}

Exception in thread "main" com.google.gson.JsonSyntaxException: com.google.gson.stream.MalformedJsonException: Expected value at line 1 column 1

UPD2:

Gson gson = new Gson();
Type list = new TypeToken<List<String>>(){}.getType();
JsonReader reader = new JsonReader(new InputStreamReader(FileReader.class.getResourceAsStream(file)));
List<String> s = gson.fromJson(reader, list);
System.out.println(s);

Answer 1

您已经标记了Jackson,但在示例中使用了Gson。我要和杰克逊一起去

String json = "{\"data\":[\"my/path/old\",\"my/path/new\"]}"; // or wherever you're getting it from

创建对象映射器

ObjectMapper mapper = new ObjectMapper();

以树的形式读取JSON字符串。因为我们知道它是一个对象，所以可以将JSONNODe强制转换为ObjectNode。

ObjectNode node = (ObjectNode)mapper.readTree(json);

JsonNode arrayNode = node.get("data");

ArrayList<String> data = mapper.readValue(arrayNode.traverse(), new TypeReference<ArrayList<String>>(){});

System.out.println(data);

给出

[my/path/old, my/path/new]