数组列表转换成JSON [英] Converting arraylist to JSON
本文介绍了数组列表转换成JSON的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我从一个servlet接收一个ArrayList的机器人活动。示例[stl1010，P3。当我尝试将其转换为JSON对象（使用解析器类），我得到的异常的错误解析数据org.json.JSONException：值[stl1010，P3]类型的org.json.JSONArray不能被转换为JSONObject的下面是servlet code：
私人的ArrayList＆LT;串GT; ticketLookup（字符串TKT）
{
连接CON = NULL;
声明ST = NULL;
//字符串数组MSGA =新的字符串数组（）;
ArrayList的＆LT;串GT; MSGA =新的ArrayList（）; 尝试
{
//这将取决于您的服务器/数据库而异
的Class.forName（com.microsoft.sqlserver.jdbc.SQLServerDriver）;
CON = DriverManager.getConnection(\"jdbc:sqlserver://serveripaddr;databaseName=dbname;user=sa;password=pwd\");
声明语句= con.createStatement（）;
结果集RS = stmt.executeQuery（选择status,description,priority,openingdate,closeddate,assigned_to,resolvergroup,assigneddatel1,impactedbyuser,emailid从ServiceRequest那里TicketNo ='+ TKT +'）;
而（rs.next（））
{// rs.getString（2）;
msga.add（将String.valueOf（rs.getString（assigned_to）））;
msga.add（将String.valueOf（rs.getString（优先权）））;
}
// JSONArray mJSONArray =新JSONArray（Arrays.asList（mStringArray））;
返回MSGA;
下面是我的Android应用程序的code（JSON解析器类+活动）。活动code：
公共无效addListenerOnGoButton（）{
btnGo.setOnClickListener（新OnClickListener（）{
公共无效的onClick（视图v）{ 字符串URL =http://10.0.2.2:8080/GnP22/GetNpostServlet?TicketNo=+ etTkt.getText（）;
字符串TAG_TICKET =准考证;
字符串TAG_STATUS =身份;
字符串TAG_DESC =说明;
字符串TAG_PRIORITY =优先级;
字符串TAG_OPENDATE =openingdate;
字符串TAG_CLOSEDATE =closingdate;
字符串TAG_ASSIGNEDTO =assignedto;
字符串TAG_RESOLVERGROUP =resolvergroup;
字符串TAG_ASSIGNEDDATEL1 =assigneddatel1;
字符串TAG_IMPACTEDUSER =impactedbyuser;
字符串TAG_EMAILID =EMAILID; //接触JSONArray
JSONArray接触= NULL; //创建JSON解析器实例
JSONParser jParser =新JSONParser（）; // URL从获取JSON字符串
JSONObject的JSON = jParser.getJSONFromUrl（URL）; 尝试{
//获取联系人的数组
接触= json.getJSONArray（TAG_TICKET）;
的for（int i = 0; I＆LT; contacts.length（）;我++）{
JSONObject的C = contacts.getJSONObject（0）; 字符串状态= c.getString（TAG_STATUS）;
字符串描述= c.getString（TAG_DESC）;
//字符串email = c.getString（TAG_EMAIL）;
//字符串的地址= c.getString（TAG_ADDRESS）;
//字符串性别= c.getString（TAG_GENDER）;
tvStatus.setText（状态）;
tvDescription.setText（介绍）;
}
}赶上（JSONException E）{
//e.printStackTrace（）;
Log.d（JSON异常，e.toString（））;
}
}
}）;}
下面是code为JSON解析器类：
公共类JSONParser { 静态InputStream为= NULL;
静态的JSONObject jObj = NULL;
静态JSON字符串=; //构造
公共JSONParser（）{ } 公众的JSONObject getJSONFromUrl（字符串URL）{ //使HTTP请求
尝试{
// defaultHttpClient
DefaultHttpClient的HttpClient =新DefaultHttpClient（）;
// HttpPost httpPost =新HttpPost（URL）;
HTTPGET httpPost =新HTTPGET（URL）; HTT presponse HTT presponse = httpClient.execute（httpPost）;
HttpEntity httpEntity = HTT presponse.getEntity（）;
是= httpEntity.getContent（）; }赶上（UnsupportedEncodingException五）{
e.printStackTrace（）;
}赶上（ClientProtocolException E）{
e.printStackTrace（）;
}赶上（IOException异常五）{
e.printStackTrace（）;
} 尝试{
读者的BufferedReader =新的BufferedReader（新的InputStreamReader（
是，ISO-8859-1），8）;
StringBuilder的SB =新的StringBuilder（）;
串线= NULL;
而（（行= reader.readLine（））！= NULL）{
sb.append（行+\\ n）;
}
is.close（）;
JSON = sb.toString（）;
}赶上（例外五）{
Log.e（缓冲区错误，错误转换结果+ e.toString（））;
} //尝试分析字符串到一个JSON对象
尝试{
jObj =新的JSONObject（JSON）;
}赶上（JSONException E）{
Log.e（JSON解析器，错误分析数据+ e.toString（））;
} //返回JSON字符串
返回jObj; }
}
解决方案
您也越来越响应数组，其中与您试图获取对象
替换
//获取JSON从URL字符串
JSONObject的JSON = jParser.getJSONFromUrl（URL）;
到
JSONArray JSON = jParser.getJSONFromUrl（URL）;
此外
公开的JSONObject getJSONFromUrl（字符串URL）{
//这会返回一个JSONObject修改此返回JSONArray
}
I have an android activity that receives an arraylist from a servlet. Example [stl1010, P3]. When I try to convert this to JSON Object (using the parser class) I get the exception "Error parsing data org.json.JSONException: Value ["stl1010","P3"] of type org.json.JSONArray cannot be converted to JSONObject." Below is the servlet code:
private ArrayList<String> ticketLookup(String tkt)
{
Connection con = null;
Statement st = null;
//StringArray msga = new StringArray();
ArrayList<String> msga = new ArrayList();
try
{
// These will vary depending on your server/database
Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
con = DriverManager.getConnection("jdbc:sqlserver://serveripaddr;databaseName=dbname;user=sa;password=pwd");
Statement stmt = con.createStatement();
ResultSet rs = stmt.executeQuery("Select status,description,priority,openingdate,closeddate,assigned_to,resolvergroup,assigneddatel1,impactedbyuser,emailid from ServiceRequest where TicketNo = '"+tkt+"'");
while (rs.next())
{
// rs.getString(2);
msga.add(String.valueOf(rs.getString("assigned_to")));
msga.add(String.valueOf(rs.getString("priority")));
}
//JSONArray mJSONArray = new JSONArray(Arrays.asList(mStringArray));
return msga;
Below is the code from my android app (JSON Parser class + activity). Activity code:
public void addListenerOnGoButton(){
btnGo.setOnClickListener(new OnClickListener()
{
public void onClick(View v) {
String url = "http://10.0.2.2:8080/GnP22/GetNpostServlet?TicketNo="+etTkt.getText();
String TAG_TICKET = "ticket";
String TAG_STATUS = "status";
String TAG_DESC = "description";
String TAG_PRIORITY = "priority";
String TAG_OPENDATE = "openingdate";
String TAG_CLOSEDATE = "closingdate";
String TAG_ASSIGNEDTO = "assignedto";
String TAG_RESOLVERGROUP = "resolvergroup";
String TAG_ASSIGNEDDATEL1 = "assigneddatel1";
String TAG_IMPACTEDUSER = "impactedbyuser";
String TAG_EMAILID = "emailid";
// contacts JSONArray
JSONArray contacts = null;
// Creating JSON Parser instance
JSONParser jParser = new JSONParser();
// getting JSON string from URL
JSONObject json = jParser.getJSONFromUrl(url);
try {
// Getting Array of Contacts
contacts = json.getJSONArray(TAG_TICKET);
for(int i = 0; i < contacts.length(); i++){
JSONObject c = contacts.getJSONObject(0);
String status = c.getString(TAG_STATUS);
String description = c.getString(TAG_DESC);
//String email = c.getString(TAG_EMAIL);
//String address = c.getString(TAG_ADDRESS);
//String gender = c.getString(TAG_GENDER);
tvStatus.setText(status);
tvDescription.setText(description);
}
} catch (JSONException e) {
//e.printStackTrace();
Log.d("JSON Exception", e.toString());
}
}
});
}
Below is the code for JSON Parser class:
public class JSONParser {
static InputStream is = null;
static JSONObject jObj = null;
static String json = "";
// constructor
public JSONParser() {
}
public JSONObject getJSONFromUrl(String url) {
// Making HTTP request
try {
// defaultHttpClient
DefaultHttpClient httpClient = new DefaultHttpClient();
//HttpPost httpPost = new HttpPost(url);
HttpGet httpPost = new HttpGet(url);
HttpResponse httpResponse = httpClient.execute(httpPost);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
try {
BufferedReader reader = new BufferedReader(new InputStreamReader(
is, "iso-8859-1"), 8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
is.close();
json = sb.toString();
} catch (Exception e) {
Log.e("Buffer Error", "Error converting result " + e.toString());
}
// try parse the string to a JSON object
try {
jObj = new JSONObject(json);
} catch (JSONException e) {
Log.e("JSON Parser", "Error parsing data " + e.toString());
}
// return JSON String
return jObj;
}
}
解决方案
You are getting an array in response where as you are trying to get an object
Replace
// getting JSON string from URL
JSONObject json = jParser.getJSONFromUrl(url);
to
JSONArray json = jParser.getJSONFromUrl(url);
Also
public JSONObject getJSONFromUrl(String url) {
//This returns a JSONObject Modify this to return JSONArray
}
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