如何修改java中的json字符串？

Question

I have a json string like

{"egcnbrandcid":5555444433332220,"egcstatus":"CARD NOT ON EGC DATABASE","egcbalance":0.00}

How can I modify the string safely in java?

By safely I mean that I still need a valid json string after I'm done modifying it. In this case I would be converting the number to a string with the output looking like:

{"egcnbrandcid":"redacted","egcstatus":"CARD NOT ON EGC DATABASE","egcbalance":0.00}  

It's important to note that the Json string won't always contain these same fields.

Answer 1

You can use JSONParser(), you don't need create java objects to save, It works like Map

 public static void main(String[] args) throws Exception  
    { 
        // parsing file "JSONExample.json" 
        Object obj = new JSONParser().parse(new FileReader("JSONExample.json")); 

        // typecasting obj to JSONObject 
        JSONObject jo = (JSONObject) obj; 

        // getting firstName and lastName 
        String firstName = (String) jo.get("firstName"); 
        String lastName = (String) jo.get("lastName"); 

        System.out.println(firstName); 
        System.out.println(lastName); 

        // getting age 
        long age = (long) jo.get("age"); 
        System.out.println(age); 

        // getting address 
        Map address = ((Map)jo.get("address")); 

        // iterating address Map 
        Iterator<Map.Entry> itr1 = address.entrySet().iterator(); 
        while (itr1.hasNext()) { 
            Map.Entry pair = itr1.next(); 
            System.out.println(pair.getKey() + " : " + pair.getValue()); 
        } 

        // getting phoneNumbers 
        JSONArray ja = (JSONArray) jo.get("phoneNumbers"); 

        // iterating phoneNumbers 
        Iterator itr2 = ja.iterator(); 

        while (itr2.hasNext())  
        { 
            itr1 = ((Map) itr2.next()).entrySet().iterator(); 
            while (itr1.hasNext()) { 
                Map.Entry pair = itr1.next(); 
                System.out.println(pair.getKey() + " : " + pair.getValue()); 
            } 
        } 

Answer 2

Inspired by @Yiao Sun's answer I wrote the following recursive functions

    private void modJO(JSONObject job){
    Iterator keys = job.keys();
    while(keys.hasNext()) {
        String currentKey = (String)keys.next();
        JSONObject job2 = job.optJSONObject(currentKey);
        JSONArray jar = job.optJSONArray(currentKey);
        // If JSON Object
        if(job2 != null){
            modJO(job2);
        }
        // If JSON Array
        else if(jar != null){
            modJA(jar);
        }
        // If JSON Property
        else {
            if(currentKey.equals("cid")){
                try{
                    job.put(currentKey,"redacted");
                }
                catch(Exception ex){}
            }
        }
    }
}

private void modJA(JSONArray jar){
    for(int i = 0; i < jar.length(); i++){
        JSONObject job = jar.optJSONObject(i);
        JSONArray jar2 = jar.optJSONArray(i);

        if (job != null){
            modJO(job);
        }
        else if (jar2 != null){
            modJA(jar2);
        }
    }
}

And I tested it on this object which should cover all possible scenarios

{
                notSecret: 'jetFuelCantMeltSteelBeams',
                cid: 'superSecret',
                obj: { cid: 'moreSecret' },
                objObj: { child: { cid: 'itsASecretToEverybody' } },
                array: [1, 2, 3],
                objArr: [{ cid: 'topSecret' }, { cid: 'iCantBelieveItsSecret' }],
                arrArr: [[1, 2], [1, 2]],
                mixed: [
                    { name: 'Waldo' },
                    { cid: 'unbelievablySecret' },
                    7,
                    [{ name: 'HeisenBurg' }, 9]
                ],
                emptyObj: {},
                emptyArr: []
            }  

Final result is

{
                objObj: { child: { cid: 'redacted' } },
                arrArr: [[1, 2], [1, 2]],
                emptyArr: [],
                array: [1, 2, 3],
                obj: { cid: 'redacted' },
                objArr: [{ cid: 'redacted' }, { cid: 'redacted' }],
                mixed: [{ name: 'Waldo' }, { cid: 'redacted' }, 7, [{ name: 'HeisenBurg' }, 9]],
                emptyObj: {},
                notSecret: 'jetFuelCantMeltSteelBeams',
                cid: 'redacted'
            }

Here's how I called it

    private String modifyJsonObject(String jsonString){
    String json = "{\"notSecret\": \"jetFuelCantMeltSteelBeams\",\"cid\": \"superSecret\",\"obj\": { \"cid\": \"moreSecret\" },\"objObj\": { \"child\": { \"cid\": \"itsASecretToEverybody\" } },\"array\": [1, 2, 3],\"objArr\": [{ \"cid\": \"topSecret\" }, { \"cid\": \"iCantBelieveItsSecret\" }], \"arrArr\": [[1, 2], [1, 2]],\"mixed\": [{ \"name\": \"Waldo\" },{ \"cid\": \"unbelievablySecret\" },7,[{ \"name\": \"HeisenBurg\" }, 9]],\"emptyObj\": {},\"emptyArr\": []}";
    try {
        JSONObject jObject  = new JSONObject(json);
        modJO(jObject);
        return jObject.toString();
    }
    catch(Exception ex){
        int stop  = 4;
    }
    return "";
}