Question

我的JSON值如下，

   { "emp_id": 1017,
   "emp_name": "karthik Y", 
  "emp_designation": "Manager", 
   "department": "JavaJson", 
   "salary": 30000, 
   "direct_reports":
  [ 
  "Nataraj G",
   "Kalyan", 
  "Mahitha" 
  ] 
} 

 HashMap < String, String[] >input1 = new HashMap < String, String[] >();
 input1.put("empid","1017");
 input1.put("emp_name","karthik");
 input1.put("emp_designation","manager");
 input1.put("salary","30000");

现在我想添加next_report的下一个数组作为下一个键和值（整个数组应该是一个键和值）。有人请帮忙。

Answer 1

Hashmap是键/值存储，其中键是唯一的。您可以将JSON转换为字符串，然后将其作为值存储到hashmap中。例如，如下所示：

before_filter :authenticate

....

protected

def authenticate
 domain = request.host
 if domain == 'www.domain.hu' 
  authenticate_or_request_with_http_basic do |username, password| username == 'stuff' && password == 'boda'
  end
 elsif domain == 'www.domain.com'
  authenticate_or_request_with_http_basic do |username, password| username == 'stuff' && password == 'boda'
 end
end
end

您还需要使用“org.json”库

手动创建JSON对象
将现有JSONObject转换为字符串表示
将JSON字符串转换为JSONObject

您还可以使用以下解决方案：

public static void main(String[] args) {
        String json = "{ \"emp_id\": 1017," 
               + "\"emp_name\": \"karthik Y\"," 
               + "\"emp_designation\": \"Manager\"," 
               + "\"department\": \"JavaJson\"," 
               + "\"salary\": 30000," 
               + "\"direct_reports\": [" 
               + "\"Nataraj G\","
               + "\"Kalyan\"," 
               + "\"Mahitha\"]}"; 

        HashMap<String, String> jsonStore = new HashMap<String, String>(); 
        jsonStore.put("myJson", json); 

        System.out.println(jsonStore.get("myJson"));
    }

确保下载org.json jar文件并将其放在类路径中以便能够使用JSONObject。您可以从here下载jar。

为了将每个值作为单个键/值条目放入映射中。你自己提到过，它应该没有任何问题。见下面的方法：

方法1 Java中的所有内容都是Object，String继承Object，String []继承对象。您可以拥有以下解决方案：

JSONObject jsonObject = new JSONObject(); 
jsonObject.put("empt_id", 1017); 
jsonObject.put("emp_name", "karthik"); 

HashMap<String, JSONObject> jsonObjectStore = new HashMap<String, JSONObject>(); 
jsonObjectStore.put("myJsonObject", jsonObject); 

HashMap<JSONObject, String> jsonObjectStore2 = new HashMap<JSONObject, String>();
jsonObjectStore2.put(jsonObject, "myJson");

方法2 要将字段存储为键/值，并且如果可以将数组转换为String（表示所有数组元素以逗号分隔，则使用此方法）。

HashMap<String, Object> myObjectStore4 = new HashMap<String, Object>();

String[] directReports4 = new String[]{"Natraj G", "Kalyan", "Mahitha"}; 

myObjectStore4.put("emp_id", new String("123")); 
myObjectStore4.put("emp_name", new String("Raf")); 
// others .... 
myObjectStore4.put("directReports", directReports4);

方法3 以Hash Map存储String key和Array值为代价。你必须把其他元素也作为数组。

HashMap<String, String> myObjectStoreTwo = new HashMap<String, String>();

String[] directReports2 = new String[]{"Natraj G", "Kalyan", "Mahitha"}; 

myObjectStoreTwo.put("emp_id", "123"); 
myObjectStoreTwo.put("emp_name", "Raf"); 
myObjectStoreTwo.put("salary", "222");

//Converts array to comma separated String 
myObjectStoreTwo.put("directReports",Arrays.toString(directReports2));

Answer 2

使用jackson ObjectMapper。试试这是否有效

String json = "{....}"
HashMap<String,Object> mappedVals = new ObjectMapper().readValue(
                    json ,
                    new TypeReference<HashMap<String,Object>>() {
                    });

将JSON值放入Hashmap

2 个答案: