다중 내부 개체가있는 GSON을 사용하여 JSON을 구문 분석합니다.

Question

GSON을 사용하여 다음 JSON 응답을 구문 분석하고 싶습니다. 보시다시피 응답에는 내부 json 객체가 많이 있습니다. 모든 내부 객체에 대해 POJO 클래스를 생성해야합니까 아니면 다른 대안이 있습니까?

{ 
    "nodeProperties": [ 
     { 
      "properties": { 
       "timeStamp": { 
        "value": 1400475483694, 
        "name": "connectedSince" 
       }, 
       "macAddress": { 
        "value": "00:00:00:00:00:03" 
       }, 
       "tables": { 
        "value": -1 
       }, 
       "capabilities": { 
        "value": 199 
       }, 
       "tier": { 
        "value": 1 
       }, 
       "supportedFlowActions": { 
        "value": "[Controller, Drop, Enqueue, HwPath, Output, PopVlan, SetDlDst, SetDlSrc, SetNwDst, SetNwSrc, SetNwTos, SetTpDst, SetTpSrc, SetVlanId, SetVlanPcp, SwPath]" 
       }, 
       "buffers": { 
        "value": 256 
       }, 
       "description": { 
        "value": "NEXT_NEWSwitch3" 
       }, 
       "forwarding": { 
        "value": 0 
       } 
      }, 
      "node": { 
       "id": "00:00:00:00:00:00:00:03", 
       "type": "OF" 
      } 
     }, 
     { 
      "properties": { 
       "timeStamp": { 
        "value": 1400475481261, 
        "name": "connectedSince" 
       }, 
       "macAddress": { 
        "value": "00:00:00:00:00:02" 
       }, 
       "tables": { 
        "value": -1 
       }, 
       "capabilities": { 
        "value": 199 
       }, 
       "tier": { 
        "value": 1 
       }, 
       "supportedFlowActions": { 
        "value": "[Controller, Drop, Enqueue, HwPath, Output, PopVlan, SetDlDst, SetDlSrc, SetNwDst, SetNwSrc, SetNwTos, SetTpDst, SetTpSrc, SetVlanId, SetVlanPcp, SwPath]" 
       }, 
       "buffers": { 
        "value": 256 
       }, 
       "description": { 
        "value": "None" 
       }, 
       "forwarding": { 
        "value": 0 
       } 
      }, 
      "node": { 
       "id": "00:00:00:00:00:00:00:02", 
       "type": "OF" 
      } 
     }, 
     { 
      "properties": { 
       "timeStamp": { 
        "value": 1400475478695, 
        "name": "connectedSince" 
       }, 
       "macAddress": { 
        "value": "00:00:00:00:00:01" 
       }, 
       "tables": { 
        "value": -1 
       }, 
       "capabilities": { 
        "value": 199 
       }, 
       "supportedFlowActions": { 
        "value": "[Controller, Drop, Enqueue, HwPath, Output, PopVlan, SetDlDst, SetDlSrc, SetNwDst, SetNwSrc, SetNwTos, SetTpDst, SetTpSrc, SetVlanId, SetVlanPcp, SwPath]" 
       }, 
       "buffers": { 
        "value": 256 
       }, 
       "description": { 
        "value": "None" 
       }, 
       "forwarding": { 
        "value": 0 
       } 
      }, 
      "node": { 
       "id": "00:00:00:00:00:00:00:01", 
       "type": "OF" 
      } 
     } 
    ] 
} 

Answer 1

JSON 문자열을 Map으로 변환하기 만하면됩니다.

샘플 코드 :

FileReader in = new FileReader(new File("resources/json3.txt")); 
BufferedReader br = new BufferedReader(in); 

// Convert JSON string into MAP object 
Gson gson = new Gson(); 
Type type = new TypeToken<Map<String, ArrayList<Map<String, Map<String, Object>>>>>() {}.getType(); 
Map<String, ArrayList<Map<String, Map<String, Object>>>> map = gson.fromJson(br, type); 

for (String key : map.keySet()) { 
    System.out.println(key); 
    for (Map<String, Map<String, Object>> value : map.get(key)) { 
     for (String k : value.keySet()) { 
      System.out.println(k); 
      for (String k1 : value.get(k).keySet()) { 
       System.out.println(k1 + ":" + value.get(k).get(k1)); 
      } 
     } 
     System.out.println("--------------"); 
    } 
} 

in.close(); 
br.close(); 

---

좀 더 간단하고 짧은있는 JSON 문자열의 복제입니다뿐만 아니라 일부 POJO 클래스를 사용하여 그것을 할 수 있습니다.

샘플 코드 :

class PropertiesNode { 
    Properties properties; 
    Node node; 
    // getter & setter 
} 

class Node { 
    String id; 
    String type; 
    // getter & setter 
} 

class Properties { 
    Map<String, Object> timeStamp; 
    Map<String, String> macAddress; 
    Map<String, Integer> tables; 
    Map<String, Integer> capabilities; 
    Map<String, Integer> tier; 
    Map<String, String> supportedFlowActions; 
    Map<String, Integer> buffers; 
    Map<String, String> description; 
    Map<String, Integer> forwarding; 
    // getter & setter 
} 

Gson gson = new Gson(); 
Type type = new TypeToken<Map<String, ArrayList<PropertiesNode>>>() {}.getType(); 
Map<String, ArrayList<PropertiesNode>> nodeProperties = gson.fromJson(br, type); 
System.out.println(new GsonBuilder().setPrettyPrinting().create().toJson(nodeProperties).toString()); 

출력 :

{ 
    "nodeProperties": [ 
     { 
     "properties": { 
      "timeStamp": { 
      "value": 1.400475483694E12, 
      "name": "connectedSince" 
      }, 
      "macAddress": { 
      "value": "00:00:00:00:00:03" 
      }, 
      "tables": { 
      "value": -1 
      }, 
      "capabilities": { 
      "value": 199 
      }, 
      "tier": { 
      "value": 1 
      }, 
      "supportedFlowActions": { 
      "value": "[Controller, Drop, Enqueue, HwPath, Output, PopVlan, SetDlDst, SetDlSrc, SetNwDst, SetNwSrc, SetNwTos, SetTpDst, SetTpSrc, SetVlanId, SetVlanPcp, SwPath]" 
      }, 
      "buffers": { 
      "value": 256 
      }, 
      "description": { 
      "value": "NEXT_NEWSwitch3" 
      }, 
      "forwarding": { 
      "value": 0 
      } 
     }, 
     "node": { 
      "id": "00:00:00:00:00:00:00:03", 
      "type": "OF" 
     } 
     }, 
     { 
     "properties": { 
      "timeStamp": { 
      "value": 1.400475481261E12, 
      "name": "connectedSince" 
      }, 
      "macAddress": { 
      "value": "00:00:00:00:00:02" 
      }, 
      "tables": { 
      "value": -1 
      }, 
      "capabilities": { 
      "value": 199 
      }, 
      "tier": { 
      "value": 1 
      }, 
      "supportedFlowActions": { 
      "value": "[Controller, Drop, Enqueue, HwPath, Output, PopVlan, SetDlDst, SetDlSrc, SetNwDst, SetNwSrc, SetNwTos, SetTpDst, SetTpSrc, SetVlanId, SetVlanPcp, SwPath]" 
      }, 
      "buffers": { 
      "value": 256 
      }, 
      "description": { 
      "value": "None" 
      }, 
      "forwarding": { 
      "value": 0 
      } 
     }, 
     "node": { 
      "id": "00:00:00:00:00:00:00:02", 
      "type": "OF" 
     } 
     }, 
     { 
     "properties": { 
      "timeStamp": { 
      "value": 1.400475478695E12, 
      "name": "connectedSince" 
      }, 
      "macAddress": { 
      "value": "00:00:00:00:00:01" 
      }, 
      "tables": { 
      "value": -1 
      }, 
      "capabilities": { 
      "value": 199 
      }, 
      "supportedFlowActions": { 
      "value": "[Controller, Drop, Enqueue, HwPath, Output, PopVlan, SetDlDst, SetDlSrc, SetNwDst, SetNwSrc, SetNwTos, SetTpDst, SetTpSrc, SetVlanId, SetVlanPcp, SwPath]" 
      }, 
      "buffers": { 
      "value": 256 
      }, 
      "description": { 
      "value": "None" 
      }, 
      "forwarding": { 
      "value": 0 
      } 
     }, 
     "node": { 
      "id": "00:00:00:00:00:00:00:01", 
      "type": "OF" 
     } 
     } 
    ] 
    }