Java中递归遍历Map数据，并替换值为null的数据-白红宇

Java中递归遍历Map数据，并替换值为null的数据

阅读量：785 次

发布时间：2019-03-25

本文共 2069 字，大约阅读时间需要 6 分钟。

项目需求分析与解决方案

当前需求针对一个JSON数据格式的处理，要求对内部结构中出现"null"值进行替换，替换为空间实137020。数据结构为：

{
  "TYPE": "FLIGHTLOAD",
  "DATA": {
    "FLIGHTID": {
      "OUTERFLIGHTID": "6A9DF3F551060192E0530B061C20F1C1",
      "CARRIER": "MF",
      "FLIGHT": "null",
      "ORIGIN": "PEK",
      "DESTINATION": "XMN",
      "SCHEDULEDEPARTURETIME": "20190312160500"
    },
    "PAYLOAD": [
      {
        "DEPARTUREAIRPORT": "PEK",
        "DESTINATIONAIRPORT": "XMN",
        "TRANSITCHILD": "null",
        "TRANSITINFANT": "null",
        "BAGGAGE": "959",
        "BAGGAGECOUNT": "959",
        "POST": "0",
        "CARGO": "1859",
        "TRANSITPOST": "null",
        "TRANSITCARGO": "null"
      }
    ]
  }

工具与解决方案

为了实现上述需求，我们开发了一套递归处理方法，该方法能够将JSON数据中的"null"值替换为空。具体实现如下：

public static void mapNullToEmpty(Map
   
     jsonResult) {
  for (Map.Entry
    
      entry : jsonResult.entrySet()) {
    String key = entry.getKey();
    Object obj = entry.getValue();
    if (obj instanceof String) {
      if ("null".equals(obj)) {
        jsonResult.put(key, "");
      }
    } else if (obj instanceof List) {
      List
     
      
       > dataList = (List
       
        
         >) obj; for (Map
         
           data : dataList) { mapNullToEmpty(data); } } else if (obj instanceof Map) { mapNullToEmpty((Map
          
           ) obj); } } }

实施效果

经过处理后的JSON数据结构如下：

{
  "TYPE": "FLIGHTLOAD",
  "DATA": {
    "FLIGHTID": {
      "OUTERFLIGHTID": "6A9DF3F551060192E0530B061C20F1C1",
      "CARRIER": "MF",
      "FLIGHT": "",
      "ORIGIN": "PEK",
      "DESTINATION": "XMN",
      "SCHEDULEDEPARTURETIME": "20190312160500"
    },
    "PAYLOAD": [
      {
        "DEPARTUREAIRPORT": "PEK",
        "DESTINATIONAIRPORT": "XMN",
        "TRANSITCHILD": "",
        "TRANSITINFANT": "",
        "BAGGAGE": "959",
        "BAGGAGECOUNT": "959",
        "POST": "0",
        "CARGO": "1859",
        "TRANSITPOST": "",
        "TRANSITCARGO": ""
      }
    ]
  }
}