Question

我正在尝试遍历我的json文件并获取所需的详细信息这是我的json

{
"000": {
    "component": "c",
    "determinantType": "dt",
    "determinant": "d",
    "header": "h",
    "determinantvalue": "null"
},
"001": {
    "component": "t",
    "determinantType": "i",
    "determinant":"ld",
    "header": "D",
    "determinantvalue": "null"
},
"002": {
    "component": "x",
    "determinantType": "id",
    "determinant": "pld",
    "header": "P",
    "determinantValue": "null"
}}

我的java代码

FileReader file = new FileReader("test.json");
Object obj = parser.parse(file);
System.out.println(obj);
JSONObject jsonObject = (JSONObject) obj;            
JSONArray msg = (JSONArray) jsonObject.get(key);          
Iterator<String> iterator = msg.iterator();         
while (iterator.hasNext()) {
System.out.println(iterator.next());            
String component = (String) jsonObject.get("component");           
System.out.println("component: " + component);

正如您在代码中看到的那样，我正在导入我的json文件并尝试从中获取下一个元素和打印组件，我还应该打印标题，行列式和行列式值以及谢谢

Answer 1

您没有数组 - 您的属性名称为“000”等。数组如下所示：

"array": [ {
    "foo": "bar1",
    "baz": "qux1"
  }, {
    "foo": "bar2",
    "baz": "qux2"
  }
]

注意[ ... ] - 表示JSON数组的内容。

您可以使用keys()

遍历JSONObject的属性

// Unfortunately keys() just returns a raw Iterator...
Iterator keys = jsonObject.keys();
while (keys.hasNext()) {
    Object key = keys.next();
    JSONObject value = jsonObject.getJSONObject((String) key);
    String component = value.getString("component");
    System.out.println(component);
}

或者：

@SuppressWarnings("unchecked")
Iterator<String> keys = (Iterator<String>) jsonObject.keys();
while (keys.hasNext()) {
    String key = keys.next();
    JSONObject value = jsonObject.getJSONObject(key);
    String component = value.getString("component");
    System.out.println(component);
}

Answer 2

不是JSONArray，只有少数JSONObjects。使用JSONObject迭代主JSONObject.keys()的键。

public static final String COMPONENT = "component";
public static final String DT = "determinantType";
public static final String D = "determinant": "d";
public static final String HEADER = "header";
public static final String DV = "determinantvalue";

JSONObject jso = getItFromSomewhere();
for (Object key : jso.keys()) {
    JSONObject subset = jso.getJSONObject(key);
    String d = subset.getString(D);
    String header = subset.getString(HEADER);
    String dv = subset.getString(DV);
    System.out.println(key + " " + header + " " + d + " " + dv);
}

Answer 3

试试这个......

FileReader file = new FileReader("test.json");
Object obj = parser.parse(file);
System.out.println(obj);
JSONObject jsonObject = (JSONObject) obj;            

Iterator<String> iterator = jsonObject .iterator();  

for(Iterator iterator = jsonObject.keySet().iterator(); iterator.hasNext();) {
    String key = (String) iterator.next();
    System.out.println(jsonObject.get(key));
}

如何在java中迭代json对象

3 个答案: