如何强制Java JSON或GSON显式命名我的数组和对象

Question

我有以下POJO:

public class Widget {
    private String fizz;
    private String buzz;
    private String foo;

    // Getters and setters for all 3...
}

在我的代码中,我试图List<List<Widget>>使用Java JSON库将a转换为JSON (但是我也接受使用GSON的任何答案).

这是我的代码:

// Returns a single List<Widget> with 2 Widgets in it...
List<List<Widget>> widgetGroups = getWidgetGroups();

String widgetGroupsAsJson = JSON.encode(widgetGroups);
System.out.println(widgetGroupsAsJson);

这打印:

[
    [
        {
            "fizz": "Yes",
            "buzz": "Never",
            "foo": "Always"
        },
        {
            "fizz": "Sometimes",
            "buzz": "Always",
            "foo": "Pending"
        }
    ]
]

而我希望JSON显示为:

"widgetGroups": [
    "widgetGroup": [
        "widget": {
            "fizz": "Yes",
            "buzz": "Never",
            "foo": "Always"
        },
        "widget": {
            "fizz": "Sometimes",
            "buzz": "Always",
            "foo": "Pending"
        }
    ]
]

换句话说,我希望所有列表以及每个列表都widget被"命名".然而,我首先担心的是,这可能不是合适的JSON.当我将第二个(所需的)JSON片段粘贴到jsonlint.org时,我得到一个解析器错误.

所以首先我要问的是,有人可以如此善良地指出我想要的JSON 应该是什么样才能做到正确; 然后第二个,如果有人可以帮助我widgetGroups按下我的列表,以便Java JSON或GSON可以产生所需的输出.提前致谢!

Answer 1

首先,你确定这是正确的吗？评论和代码不匹配.

// Returns a single List<Widget> with 2 Widgets in it...
List<List<Widget>> widgetGroups = getWidgetGroups();

其次,创建一个WidgetGroup类,它将充当单个WidgetGroup的容器.

public class WidgetGroup {

    private String name;
    private List<Widget> widgets;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public List<Widget> getWidgets() {
        return widgets;
    }

    public void setWidgets(List<Widget> widgets) {
        this.widgets = widgets;
    }
}

这将是一个有效的JSON结构:

{
  "widgetGroups" : [
    {
      "widgetGroup": [
        "widget": {
          "fizz": "Yes",
          "buzz": "Never",
          "foo": "Always"
        },
        /*More widgets*/
      ]
    },
    /*More widget groups*/
  ]
}

这样的事情应该有效:

Map<String, List<WidgetGroup>> widgetGroups = new HashMap<String, List<WidgetGroup>>();
WidgetGroup widgetGroup1 = getWidgetGroup(); // Just an assumption of one of your methods.
WidgetGroup widgetGroup2 = getWidgetGroup(); // Just an assumption of one of your methods.

List<WidgetGroup> widgetGroupList = new ArrayList<WidgetGroup>();
widgetGroupList.add(widgetGroup1);
widgetGroupList.add(widgetGroup2);

widgetGroups.put("widgetGroups", widgetGroupList);

然后你打电话toJson()给地图.