Question

我是Android平台的新手，我想通过JSON Parser从PHP Web服务获取值。但我没有得到数据，而是错误：No value for data25 ,data26 and data27。

感谢您解决此问题的任何帮助。

try{
            JSONArray jArray = new JSONArray(result);
            for(int i=0;i<jArray.length();i++)
            {
            HashMap<String, String> map = new HashMap<String, String>();

              JSONObject json_data = jArray.getJSONObject(i);

            map.put("data25", "date25:" + json_data.getString("data25"));
            map.put("data26", "data26:" + json_data.getString("data26"));
            map.put("data27", "data27:" + json_data.getString("data27"));

            mylist.add(map);

            }

JSON结果如下：

[
{
    "data1": "5794",
    "data2": "2922",
    "data3": "6799",
    "data4": "2729",
    "data5": "9860",
    "data6": "4486",
    "data7": "9903",
    "data8": "0113",
    "data9": "9936",
    "data10": "5470",
    "data11": "7423",
    "data12": "1237",
    "data13": "6564",
    "data14": "1261",
    "data15": "4730",
    "data16": "7714",
    "data17": "2410",
    "data18": "7486",
    "data19": "7046",
    "data20": "8263",
    "data21": "4305",
    "data22": "6244",
    "data23": "2495",
    "data24": " 19\/09\/2012(Wed)"
},
{
    "data1": "555",
    "data2": "039",
    "data3": "353",
    "data4": "1438",
    "data5": "8720",
    "data6": "7490",
    "data7": "1294",
    "data8": "4000",
    "data9": "6017",
    "data10": "2294",
    "data11": "4042",
    "data12": "0064",
    "data13": "8441",
    "data14": "1252",
    "data15": "9609",
    "data16": "0797",
    "data17": "1680",
    "data18": "0917",
    "data19": "7492",
    "data20": "9488",
    "data21": "3253",
    "data22": "7915",
    "data23": "1071",
    "data24": " 19\/09\/2012(Wed)",
    //--heredata25,
    data26,
    data27----------"data25": "9555",
    "data26": "3039",
    "data27": "6353"
},
{
    "data1": "0395",
    "data2": "5928",
    "data3": "8998",
    "data4": "6447",
    "data5": "1827",
    "data6": "8131",
    "data7": "7454",
    "data8": "4647",
    "data9": "1892",
    "data10": "3656",
    "data11": "1989",
    "data12": "9095",
    "data13": "6826",
    "data14": "1860",
    "data15": "9766",
    "data16": "6069",
    "data17": "6050",
    "data18": "6526",
    "data19": "8392",
    "data20": "0520",
    "data21": "7540",
    "data22": "3608",
    "data23": "7430",
    "data24": " 19\/09\/2012(Wed)"
},

Answer 1

根据您发布的响应，它是JSONArray的JSONArray。每个JSONObject都包含带有data1，data2 ... etch等键的值。但是每个JSONObject都不包含密钥data25，data26，data27。如果您不想抛出异常，即使响应不包含每个JSONObject中的data25，data26，data27键，那么您需要修改如下代码：

        JSONArray jArray = new JSONArray(result);
        for(int i=0;i<jArray.length();i++)
        {
        HashMap<String, String> map = new HashMap<String, String>();

          // getJSONObject() will throw exception if the key is not found in the jsonObject. Instead of it use optJSONObject() to get the values from JSONObject. It returns the value if contains otherwise returns the empty jsonObject.
          // JSONObject json_data = jArray.getJSONObject(i);
          JSONObject json_data = jArray.optJSONObject(i);


        //map.put("data25", "date25:" + json_data.getString("data25"));
         map.put("data25", "date25:" + json_data.optString("data25")); // returns empty string on not finding the key in JSONObject.

        //map.put("data26", "data26:" + json_data.getString("data26"));
        //map.put("data27", "data27:" + json_data.getString("data27"));

        mylist.add(map);

        }

如何从php webservice获取JSON数据：“没有数据值”错误

1 个答案: