将对象的 JSON 数组转换为 List<String>

Question

我有一段 JSON 中的选择数据，我想将它转换为 Java ArrayList。

String q = "SELECT attributes FROM common_attr_test";

PreparedStatement preparedStatement = (PreparedStatement) conn.prepareStatement(q);

preparedStatement.execute();

ResultSet rs = preparedStatement.executeQuery();

while (rs.next()) {

    valueAttributes = rs.getString("attributes");

} 

JSONObject obj=(JSONObject)JSONValue.parse(valueAttributes); 

JSONArray arrOne=(JSONArray)obj.get("1"); 

System.out.println(arrOne);

从代码中，我得到以下结果：

[{"entry":"1","count":1},{"entry":"2","count":1},{"entry":"3","count":1}]

我尝试使用编码

ArrayList<String> listOne = new ArrayList<String>();

if (arrOne != null) { 

    int len = arrOne.size();

    for (int i=0;i<len;i++){ 

        listOne.add(arrOne.get(i).toString());

    } 

} 

System.out.println(arrOne);

System.out.println("\nlistOne:"+listOne);

并得到结果：

[{"entry":"2","count":3}]

我的问题是如何将结果放入 Java 中的 ArrayList 中，如下所示：

[(1,1),(2,1),(3,1)]

Answer 1

您需要遍历您的JSONArray，将每个元素转换为 aJSONObject并从每个元素中提取entry和count值，然后从中创建一个字符串并添加到您的列表中：if (arrOne != null) {&nbsp; &nbsp; JSONObject entryCountJson;&nbsp; &nbsp; String entry, count;&nbsp; &nbsp; for (Object o : arrOne) {&nbsp; &nbsp; &nbsp; &nbsp; entryCountJson = (JSONObject) o;&nbsp; &nbsp; &nbsp; &nbsp; entry = String.valueOf(entryCountJson.get("entry"));&nbsp; &nbsp; &nbsp; &nbsp; count = String.valueOf(entryCountJson.get("count"));&nbsp; &nbsp; &nbsp; &nbsp; listOne.add("(" + entry + "," + count + ")");&nbsp; &nbsp; }}System.out.println("arrOne: "+arrOne);System.out.println("listOne: "+listOne);这输出：arrOne: [{"entry":"1","count":1},{"entry":"2","count":1},{"entry":"3","count":1}]listOne: [(1,1), (2,1), (3,1)]