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 2008 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": ""      }    ]  }}