使用JSON.simple解析嵌套JSON数组，如何获取param3的参数值？

Hey there! You're already doing a solid job parsing the top-level parameters with JSON.simple—let's tackle that nested param3 array next.

Since param3 is another JSON array (just like your top-level example array), we can reuse the same iterator pattern you already have, just one level deeper. Here's how to implement it:

First, Update Your ExampleClass #

Let's add a nested class or dedicated structure to hold the param3 values (adjust this to match your actual data model):

class ExampleClass {
    double param1;
    long param2;
    List<Param3Data> param3Items = new ArrayList<>();

    // Nested class to store param3's inner values
    static class Param3Data {
        long param3_1;
        String param3_2;
    }
}

Add the Parsing Logic for param3 #

Replace the ..... in your case "param3" block with this code:

case "param3":
    // Cast the value to JSONArray since param3 is an array
    JSONArray param3Array = (JSONArray) pair.getValue();
    if (param3Array != null) {
        Iterator param3Iterator = param3Array.iterator();
        while (param3Iterator.hasNext()) {
            ExampleClass.Param3Data param3Obj = new ExampleClass.Param3Data();
            // Get the nested JSONObject from the array (JSON.simple maps objects to Map)
            Map param3Map = (Map) param3Iterator.next();
            Iterator<Map.Entry> param3MapIterator = param3Map.entrySet().iterator();
            
            // Iterate over the nested object's entries
            while (param3MapIterator.hasNext()) {
                Map.Entry param3Pair = param3MapIterator.next();
                switch (param3Pair.getKey().toString()) {
                    case "param3_1":
                        param3Obj.param3_1 = (long) param3Pair.getValue();
                        break;
                    case "param3_2":
                        param3Obj.param3_2 = (String) param3Pair.getValue();
                        break;
                    default:
                        break;
                }
            }
            // Add the parsed param3 object to your ExampleClass list
            e.param3Items.add(param3Obj);
        }
    }
    break;

How This Works #

1. Cast to JSONArray: We first convert the param3 value from the parent object to a JSONArray (since it's wrapped in []).
2. Iterate the Nested Array: We use an iterator to loop through each object inside param3.
3. Parse the Inner JSONObject: Each element in the param3 array is a JSON object, which JSON.simple represents as a Java Map. We iterate over this map's entries to extract param3_1 and param3_2.
4. Store the Data: We populate the nested Param3Data class and add it to the list in your ExampleClass.

This follows the exact same pattern you already used for the top-level example array—just applied one level deeper!

内容的提问来源于stack exchange，提问作者Mitch