使用GSON将JSON字符串转换为POJO，需要澄清

Question

I have a JSON file, as String :

    String compString = "{\n" +
            "      \"Component\": {\n" +
            "        \"name\": \"Application\",\n" +
            "        \"environment\": \"QA\",\n" +
            "        \"hosts\": [\n" +
            "          \"box1\",\n" +
            "          \"box2\"\n" +
            "        ],\n" +
            "        \"directories\": [\n" +
            "          \"/path/to/dir1/\",\n" +
            "          \"/path/to/dir2/\",\n" +
            "          \"/path/to/dir1/subdir/\",\n" +
            "        ]\n" +
            "      }\n" +
            "    }";

I have a bean representing it (correct if incorrectly)

public class Component {

    String name;
    String environment;

    List<String> hosts = new ArrayList<String>();
    List<String> directories = new ArrayList<String>();

    // standard getters and setters
}

I am trying to feed this String to this class by:

    Gson gson = new Gson();
    Component component = gson.fromJson(compString, Component.class);

    System.out.println(component.getName());

Above does not work. (I am getting null back, as if Component's name value is never set)

What am i missing please?

Answer 1

In fact, you have to remove the enclosing class from Json.

Indeed, JSON begins with the content of the enclosing class.

So your JSON would be:

 String compString = "{\n" +
                    "        \"name\": \"Application\",\n" +
                    "        \"environment\": \"QA\",\n" +
                    "        \"hosts\": [\n" +
                    "          \"box1\",\n" +
                    "          \"box2\"\n" +
                    "        ],\n" +
                    "        \"directories\": [\n" +
                    "          \"/path/to/dir1/\",\n" +
                    "          \"/path/to/dir2/\",\n" +
                    "          \"/path/to/dir1/subdir/\",\n" +
                    "        ]\n" +
                    "      }\n";

Answer 2

String compString = 
                "       {\n" +
                "        \"name\": \"Application\",\n" +
                "        \"environment\": \"QA\",\n" +
                "        \"hosts\": [\n" +
                "          \"box1\",\n" +
                "          \"box2\"\n" +
                "        ],\n" +
                "        \"directories\": [\n" +
                "          \"/path/to/dir1/\",\n" +
                "          \"/path/to/dir2/\",\n" +
                "          \"/path/to/dir1/subdir/\",\n" +
                "        ]}" ;

I think you should read more about json, I have removed something in your json string and then success.