get specified value from Json Array - java

how r u
I need to access a database and read data from a table then get the values of it so I create a php file to print a database in JSON format to access data:
<?php
try{
$db=new PDO('mysql:host=localhost;dbname='database','table','password');
$row=$db->prepare('select * from users' );
$row->execute();
$json_data=array();
foreach($row as $rec)
{
$json_array['userId']=$rec['userId'];
$json_array['user']=$rec['user'];
$json_array['pass']=$rec['pass'];
$json_array['name']=$rec['name'];
$json_array['family']=$rec['family'];
$json_array['gender']=$rec['gender'];
$json_array['birthday']=$rec['birthday'];
array_push($json_data,$json_array);
}
echo json_encode($json_data);
} catch(PDOExcetion $e)
{
print "Error: " . $e->getMessage()."<br/>";
die();
}
?>
and this is the output:
[
{"userId":"1","user":"saly","pass":"666","name":"SalyR","family":"manson","gender":"male","birthday":"1988\/11\/10"},
{"userId":"1","user":"foo","pass":"2657","name":"foo","family":"rocki","gender":"male","birthday":"13989\/2\/07"},
{"userId":"1","user":"mil","pass":"63495","name":"milo","family":"toufa","gender":"male","birthday":"13987\/04\/21"},
{"userId":"1","user":"soos","pass":"03468","name":"soro","family":"radi","gender":"female","birthday":"13990\/08\/09"}
]
I wanna get access to specified value like 'userId' and 'name' and 'birthday'.
I use three methods to get values:
1) getJSONFromDatabase method gets a database URL and returns an JSON String.
public String getJSONFromDatabase(String getDatabaseURL) {
HttpClient client = new DefaultHttpClient();
HttpPost method = new HttpPost(getDatabaseURL);
String result = "";
try {
HttpResponse response = client.execute(method);
int code = response.getStatusLine().getStatusCode();
InputStream stream = response.getEntity().getContent();
result = inputstreamToString(stream);
Log.i("LOG", "Code :" + code);
} catch (IOException e) {
Log.e("Database", "Error Connect to Database!");
e.printStackTrace();
}
return result;
}
2) inputstreamToString method gets an Inputstream and read all lines.
private String inputstreamToString(InputStream getStream) {
BufferedReader reader = new BufferedReader(new InputStreamReader(getStream));
StringBuilder builder = new StringBuilder();
String line;
try {
while ((line = reader.readLine()) != null) {
builder.append(line);
}
return builder.toString();
} catch (IOException e) {
Log.e("Reader", "Error reading stream!");
e.printStackTrace();
}
return "";
}
3) jsonToString method gets JSON String with a String value that we want to get.
public String jsonToString(String getJSONString, String value) {
String userId = "";
try {
JSONObject object = new JSONObject(getJSONString);
userId = object.getString(value);
return userId;
} catch (JSONException e) {
Log.e("JSON", "Error converting!");
e.printStackTrace();
}
return "";
}
so I call methods like this:
String databaseURL = "http://192.168.56.1/saly/getDatabaseTable.php";
String jsonFormat = getJSONFromDatabase(databaseURL);
String userId = jsonToString(jsonFormat, "userId");
String name= jsonToString(jsonFormat, "name");
String birthday= jsonToString(jsonFormat, "birthday");
at the end I get this errors in Log:
JSON: Error converting!
JSON: Error converting!
JSON: Error converting!
when I remove [ ] and write one line just like this JSON String, it works properly, just one line!:
{
"userId":"1",
"user":"saly",
"pass":"666",
"name":"SalyR",
"family":"manson",
"gender":"male",
"birthday":"1988\/11\/10"
}
but it's not gonna work for me because when I print all table of database in JSON format the whole data will print.
I wrote too much and sorry for that, I tried explanation every things.
would you gyus please help me where I wrong?
thank you.

You have to parse it as jsonArray. The following snip will help you.
JSONArray jsonarray = new JSONArray(str);//str= your json string.
for(int i=0; i<jsonarray.length(); i++){
JSONObject obj = jsonarray.getJSONObject(i);
String name = obj.getString("name");
String url = obj.getString("url");
System.out.println(name);
System.out.println(url);
}
Here is the answer for this question.

User.java
it's the user class.
public class User {
private String userId = "";
private String user = "";
private String pass = "";
private String name = "";
private String family = "";
private String gender = "";
private String birthday = "";
public String getUserId() {
return userId;
}
public void setUserId(String userId) {
this.userId = userId;
}
public String getUser() {
return user;
}
public void setUser(String user) {
this.user = user;
}
public String getPass() {
return pass;
}
public void setPass(String pass) {
this.pass = pass;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getFamily() {
return family;
}
public void setFamily(String family) {
this.family = family;
}
public String getGender() {
return gender;
}
public void setGender(String gender) {
this.gender = gender;
}
public String getBirthday() {
return birthday;
}
public void setBirthday(String birthday) {
this.birthday = birthday;
}
#Override
public String toString() {
// TODO Auto-generated method stub
return userId+" "+user+ " "+pass+ " "+name+" "+family+" "+ gender+ " "+ " ";
}
}
you can run this as a test, this example shows how easy it would be to deal with JSON by using Gson library
public class SIx {
public static void main(String[] args) {
ArrayList<User> list = new ArrayList<User>();
System.out.println("#### Object ####");
for (int i = 0; i < 4; i++) {
User user = new User();
user.setUserId("UserId_"+i);
user.setUser("User_"+i);
user.setPass("Pass_"+i);
user.setName("Name_"+i);
user.setGender("Gender_"+i);
user.setFamily("Family_"+i);
user.setBirthday("Birthday_"+i);
list.add(user);
System.out.println(user.toString());
}
String string = (new Gson()).toJson(list);
System.out.println();
System.out.println();
System.out.println(string);
System.out.println();
System.out.println();
ArrayList<User> newList = (new Gson()).fromJson(string, new TypeToken<ArrayList<User>>() {}.getType());
for (int i = 0; i < newList.size(); i++) {
User user = newList.get(i);
System.out.println("UserId_: "+user.getUserId());
System.out.println("User_: "+user.getUser());
System.out.println("Pass_: "+user.getPass());
System.out.println("Name_: "+user.getName());
System.out.println("Gender_: "+user.getGender());
System.out.println("Family_: "+user.getFamily());
System.out.println("Birthday_: "+user.getBirthday());
System.out.println();
}
}
}
output

Related

Confused on how to use BufferedReader for reading arraylist of User objects

After the user is registered, they can login which is supposed to read their details from a text file by using a BufferedReader. However, I am unsure of how to use a BufferedReader to read the arraylist of User objects line by line to check the details are in the text file and allow for the user to login.
This is what I have written:
public class LoginJFrame extends javax.swing.JFrame {
ArrayList<User> users = new ArrayList<>();
public LoginJFrame() {
initComponents();
}
private void btnLoginActionPerformed(java.awt.event.ActionEvent evt) {
String nickname = edtNickname.getText();
String loginID = edtLoginID.getText();
String password = String.valueOf(edtPassword.getPassword());
try {
BufferedReader br = new BufferedReader(new FileReader("userinfo.txt"));
String readFile = br.readLine();
while (readFile != null) {
String[] splitString = readFile.split(",");
nickname = splitString[0];
loginID = splitString[1];
password = splitString[2];
User user = new User(nickname, loginID, password);
users.add(user);
readFile = br.readLine();
this.dispose();
ThreadJFrame threadPage = new ThreadJFrame();
threadPage.setVisible(true);
}
} catch (Exception e) {
e.printStackTrace();
}
}
The only reason why I have another arrayList that is a string is because I cannot figure out a way for the BufferedReader to read my User arrayList line by line. Is there a way for the BufferedReader to read the arraylist class type instead of a string ArrayList?
The User object is a separate class that stores the nickname, login ID and password by using a string.
public class User {
String nickname;
String loginID;
String password;
public User(String nickname, String loginID, String password) {
this.nickname = nickname;
this.loginID = loginID;
this.password = password;
}
public String getNickname() {
return nickname;
}
public String getLoginID() {
return loginID;
}
public String getPassword() {
return password;
}
public void setNickname(String nickname) {
this.nickname = nickname;
}
public void setLoginID(String loginID) {
this.loginID = loginID;
}
public void setPassword(String password) {
this.password = password;
}
#Override
public String toString() {
return "User{" + "nickname= " + nickname + ", loginID= " + loginID + ", password= " + password + '}';
}
currentLine = br.readLine();
while (currentLine != null) {
userstring.add(currentLine);
}
Well, that code only reads a single line since you only ever invoke the readline() method once.
The code should be something like:
currentLine = br.readLine();
while (currentLine != null) {
userstring.add(currentLine);
currentLine = br.readLine();
}
And since your data for the User is contained in a single line (since you just save the toString() of your User class) you will need to parse the data into its individual tokens probably by using the String.split(...) method.
Of course your readToFile(...) method won't really do anything because you define the ArrayList locally and don't return any data from the method so the rest of your class can't access the data.

Read json list in java

Previously I was reading json data in the following format:
JSON
{
"CreationTime":"2018-01-12T12:32:31",
"Id":"08f81fd7-21f1-48ba-a991-08d559b88cc5",
"Operation":"AddedToGroup",
"RecordType":14,
"UserType":0,
"Version":1,
"Workload":"OneDrive",
"ClientIP":"115.186.129.229",
"UserId":"omaji7#emumbaa10.onmicrosoft.com",
"EventSource":"SharePoint",
"ItemType":"Web"
}
I am reading this json data from a kafka topic and doing some stream processing on it and passing it onto another topic. In processing I have created two json objects, send and received.
Using this code:
final StreamsBuilder builder = new StreamsBuilder();
KStream<String, String> source_o365_user_activity = builder.stream("o365_user_activity");
source_o365_user_activity.flatMapValues(new ValueMapper<String, Iterable<String>>() {
#Override
public Iterable<String> apply(String value) {
System.out.println("========> o365_user_activity_by_date Log: " + value);
ArrayList<String> keywords = new ArrayList<String>();
try {
JSONObject send = new JSONObject();
JSONObject received = new JSONObject(value);
send.put("current_date", getCurrentDate().toString()); // UTC TIME
send.put("activity_time", received.get("CreationTime")); // CONSTANTS FINAL STATIC(Topic Names, Cassandra keys)
send.put("user_id", received.get("UserId"));
send.put("operation_type", received.get("Operation"));
send.put("app_name", received.get("Workload"));
keywords.add(send.toString());
// apply regex to value and for each match add it to keywords
} catch (Exception e) {
// TODO: handle exception
System.err.println("Unable to convert to json");
e.printStackTrace();
}
return keywords;
}
}).to("o365_user_activity_by_date");
This was fairly simple. Now I have a json data with lists in them.
JSON
{
"CreationTime":"2017-12-27T07:47:46",
"Id":"10ee505b-90a4-4ac1-b96f-a6dbca939694",
"Operation":"Add member to role.",
"OrganizationId":"2f88f444-62da-4aae-b8af-8331a6915801",
"RecordType":8,
"ResultStatus":"success",
"UserKey":"10030000A656FE5B#emumbaa10.onmicrosoft.com",
"UserType":0,
"Version":1,
"Workload":"AzureActiveDirectory",
"ObjectId":"mustafa#emumbaa10.onmicrosoft.com",
"UserId":"omaji7#emumbaa10.onmicrosoft.com",
"AzureActiveDirectoryEventType":1,
"ExtendedProperties":[
{
"Name":"Role.ObjectID",
"Value":"b0f54661-2d74-4c50-afa3-1ec803f12efe"
},
{
"Name":"Role.DisplayName",
"Value":"Billing Administrator"
},
{
"Name":"Role.TemplateId",
"Value":"b0f54661-2d74-4c50-afa3-1ec803f12efe"
},
{
"Name":"Role.WellKnownObjectName",
"Value":"BillingAdmins"
}
],
"Actor":[
{
"ID":"omaji7#emumbaa10.onmicrosoft.com",
"Type":5
},
{
"ID":"10030000A656FE5B",
"Type":3
},
{
"ID":"User_d03ca514-adfa-4585-a8bd-7182a9a086c7",
"Type":2
}
],
"ActorContextId":"2f88f444-62da-4aae-b8af-8331a6915801",
"InterSystemsId":"6d402a5b-c5de-4d9f-a805-9371c109e55f",
"IntraSystemId":"a5568d01-f100-497a-b88b-c9731ff31248",
"Target":[
{
"ID":"User_8f77c311-3ea0-4146-9f7d-db21bd052d3d",
"Type":2
},
{
"ID":"mustafa#emumbaa10.onmicrosoft.com",
"Type":5
},
{
"ID":"1003BFFDA67CCA03",
"Type":3
}
],
"TargetContextId":"2f88f444-62da-4aae-b8af-8331a6915801"
}
How can I go about doing the same thing in my Stream processing?
I want to be able to read JSON data against some keys (including the list data keys).
Why not convert JSON to Object and then filter against using the field in Object?
Can't you do like this?
send.put("target_0_id", received.get("Target").getJSONObject(0).get("ID"));
You can use gson library and can convert the json to object and using getter and setter you can build your desired output JSON. You can also parse the input JSON to fetch the JSONArray details. Following is the code how you can do it using POJO.
Input class:
public class Input {
private String UserType;
private String TargetContextId;
private String RecordType;
private String Operation;
private String Workload;
private String UserId;
private String OrganizationId;
private String InterSystemsId;
private ExtendedProperties[] ExtendedProperties;
private String ActorContextId;
private String CreationTime;
private String IntraSystemId;
private Target[] Target;
private Actor[] Actor;
private String Id;
private String Version;
private String ResultStatus;
private String ObjectId;
private String AzureActiveDirectoryEventType;
private String UserKey;
public String getUserType ()
{
return UserType;
}
public void setUserType (String UserType)
{
this.UserType = UserType;
}
public String getTargetContextId ()
{
return TargetContextId;
}
public void setTargetContextId (String TargetContextId)
{
this.TargetContextId = TargetContextId;
}
public String getRecordType ()
{
return RecordType;
}
public void setRecordType (String RecordType)
{
this.RecordType = RecordType;
}
public String getOperation ()
{
return Operation;
}
public void setOperation (String Operation)
{
this.Operation = Operation;
}
public String getWorkload ()
{
return Workload;
}
public void setWorkload (String Workload)
{
this.Workload = Workload;
}
public String getUserId ()
{
return UserId;
}
public void setUserId (String UserId)
{
this.UserId = UserId;
}
public String getOrganizationId ()
{
return OrganizationId;
}
public void setOrganizationId (String OrganizationId)
{
this.OrganizationId = OrganizationId;
}
public String getInterSystemsId ()
{
return InterSystemsId;
}
public void setInterSystemsId (String InterSystemsId)
{
this.InterSystemsId = InterSystemsId;
}
public ExtendedProperties[] getExtendedProperties ()
{
return ExtendedProperties;
}
public void setExtendedProperties (ExtendedProperties[] ExtendedProperties)
{
this.ExtendedProperties = ExtendedProperties;
}
public String getActorContextId ()
{
return ActorContextId;
}
public void setActorContextId (String ActorContextId)
{
this.ActorContextId = ActorContextId;
}
public String getCreationTime ()
{
return CreationTime;
}
public void setCreationTime (String CreationTime)
{
this.CreationTime = CreationTime;
}
public String getIntraSystemId ()
{
return IntraSystemId;
}
public void setIntraSystemId (String IntraSystemId)
{
this.IntraSystemId = IntraSystemId;
}
public Target[] getTarget ()
{
return Target;
}
public void setTarget (Target[] Target)
{
this.Target = Target;
}
public Actor[] getActor ()
{
return Actor;
}
public void setActor (Actor[] Actor)
{
this.Actor = Actor;
}
public String getId ()
{
return Id;
}
public void setId (String Id)
{
this.Id = Id;
}
public String getVersion ()
{
return Version;
}
public void setVersion (String Version)
{
this.Version = Version;
}
public String getResultStatus ()
{
return ResultStatus;
}
public void setResultStatus (String ResultStatus)
{
this.ResultStatus = ResultStatus;
}
public String getObjectId ()
{
return ObjectId;
}
public void setObjectId (String ObjectId)
{
this.ObjectId = ObjectId;
}
public String getAzureActiveDirectoryEventType ()
{
return AzureActiveDirectoryEventType;
}
public void setAzureActiveDirectoryEventType (String AzureActiveDirectoryEventType)
{
this.AzureActiveDirectoryEventType = AzureActiveDirectoryEventType;
}
public String getUserKey ()
{
return UserKey;
}
public void setUserKey (String UserKey)
{
this.UserKey = UserKey;
}
#Override
public String toString()
{
return "ClassPojo [UserType = "+UserType+", TargetContextId = "+TargetContextId+", RecordType = "+RecordType+", Operation = "+Operation+", Workload = "+Workload+", UserId = "+UserId+", OrganizationId = "+OrganizationId+", InterSystemsId = "+InterSystemsId+", ExtendedProperties = "+ExtendedProperties+", ActorContextId = "+ActorContextId+", CreationTime = "+CreationTime+", IntraSystemId = "+IntraSystemId+", Target = "+Target+", Actor = "+Actor+", Id = "+Id+", Version = "+Version+", ResultStatus = "+ResultStatus+", ObjectId = "+ObjectId+", AzureActiveDirectoryEventType = "+AzureActiveDirectoryEventType+", UserKey = "+UserKey+"]";
}}
Target class:
public class Target {
private String Type;
private String ID;
public String getType() {
return Type;
}
public void setType(String Type) {
this.Type = Type;
}
public String getID() {
return ID;
}
public void setID(String ID) {
this.ID = ID;
}
#Override
public String toString() {
return "ClassPojo [Type = " + Type + ", ID = " + ID + "]";
}}
Actor class :
public class Actor {
private String Type;
private String ID;
public String getType() {
return Type;
}
public void setType(String Type) {
this.Type = Type;
}
public String getID() {
return ID;
}
public void setID(String ID) {
this.ID = ID;
}
#Override
public String toString() {
return "ClassPojo [Type = " + Type + ", ID = " + ID + "]";
}}
ExtendedProperties class :
public class ExtendedProperties {
private String Name;
private String Value;
public String getName() {
return Name;
}
public void setName(String Name) {
this.Name = Name;
}
public String getValue() {
return Value;
}
public void setValue(String Value) {
this.Value = Value;
}
#Override
public String toString() {
return "ClassPojo [Name = " + Name + ", Value = " + Value + "]";
}}
Main class :
public class Stack {
public static void main(String[] args) {
doIt();
}
private static void doIt() {
String received = "{\"CreationTime\":\"2017-12-27T07:47:46\",\"Id\":\"10ee505b-90a4-4ac1-b96f-a6dbca939694\",\"Operation\":\"Add member to role.\",\"OrganizationId\":\"2f88f444-62da-4aae-b8af-8331a6915801\",\"RecordType\":8,\"ResultStatus\":\"success\",\"UserKey\":\"10030000A656FE5B#emumbaa10.onmicrosoft.com\",\"UserType\":0,\"Version\":1,\"Workload\":\"AzureActiveDirectory\",\"ObjectId\":\"mustafa#emumbaa10.onmicrosoft.com\",\"UserId\":\"omaji7#emumbaa10.onmicrosoft.com\",\"AzureActiveDirectoryEventType\":1,\"ExtendedProperties\":[{\"Name\":\"Role.ObjectID\",\"Value\":\"b0f54661-2d74-4c50-afa3-1ec803f12efe\"},{\"Name\":\"Role.DisplayName\",\"Value\":\"Billing Administrator\"},{\"Name\":\"Role.TemplateId\",\"Value\":\"b0f54661-2d74-4c50-afa3-1ec803f12efe\"},{\"Name\":\"Role.WellKnownObjectName\",\"Value\":\"BillingAdmins\"}],\"Actor\":[{\"ID\":\"omaji7#emumbaa10.onmicrosoft.com\",\"Type\":5},{\"ID\":\"10030000A656FE5B\",\"Type\":3},{\"ID\":\"User_d03ca514-adfa-4585-a8bd-7182a9a086c7\",\"Type\":2}],\"ActorContextId\":\"2f88f444-62da-4aae-b8af-8331a6915801\",\"InterSystemsId\":\"6d402a5b-c5de-4d9f-a805-9371c109e55f\",\"IntraSystemId\":\"a5568d01-f100-497a-b88b-c9731ff31248\",\"Target\":[{\"ID\":\"User_8f77c311-3ea0-4146-9f7d-db21bd052d3d\",\"Type\":2},{\"ID\":\"mustafa#emumbaa10.onmicrosoft.com\",\"Type\":5},{\"ID\":\"1003BFFDA67CCA03\",\"Type\":3}],\"TargetContextId\":\"2f88f444-62da-4aae-b8af-8331a6915801\"}";
JSONObject send = new JSONObject();
Gson gson = new Gson();
Input inputObject = gson.fromJson(received, Input.class);
// you can add values here and customize the output JSON
send.put("userId", inputObject.getUserId());
send.put("Workload", inputObject.getWorkload());
// read Actor list
Actor[] arr = inputObject.getActor();
for (int i = 0; i < arr.length; i++) {
// write your logic here how you want to handle the Actor list
// values
System.out.println(arr[i].getID() + " : " + arr[i].getType());
}
// read ExtendedProperties list
ExtendedProperties[] extendedProperties = inputObject.getExtendedProperties();
for (int j = 0; j < extendedProperties.length; j++) {
// write your logic here how you want to handle the
// ExtendedProperties list values
System.out.println(extendedProperties[j].getName() + " : " + extendedProperties[j].getValue());
}
System.out.println("*************");
}}
alternate main class without using POJO. Here org.json library have been used to parse the input JSON.
public class Test {
public static void main(String[] args) {
doIt();
}
private static void doIt() {
String received = "{\"CreationTime\":\"2017-12-27T07:47:46\",\"Id\":\"10ee505b-90a4-4ac1-b96f-a6dbca939694\",\"Operation\":\"Add member to role.\",\"OrganizationId\":\"2f88f444-62da-4aae-b8af-8331a6915801\",\"RecordType\":8,\"ResultStatus\":\"success\",\"UserKey\":\"10030000A656FE5B#emumbaa10.onmicrosoft.com\",\"UserType\":0,\"Version\":1,\"Workload\":\"AzureActiveDirectory\",\"ObjectId\":\"mustafa#emumbaa10.onmicrosoft.com\",\"UserId\":\"omaji7#emumbaa10.onmicrosoft.com\",\"AzureActiveDirectoryEventType\":1,\"ExtendedProperties\":[{\"Name\":\"Role.ObjectID\",\"Value\":\"b0f54661-2d74-4c50-afa3-1ec803f12efe\"},{\"Name\":\"Role.DisplayName\",\"Value\":\"Billing Administrator\"},{\"Name\":\"Role.TemplateId\",\"Value\":\"b0f54661-2d74-4c50-afa3-1ec803f12efe\"},{\"Name\":\"Role.WellKnownObjectName\",\"Value\":\"BillingAdmins\"}],\"Actor\":[{\"ID\":\"omaji7#emumbaa10.onmicrosoft.com\",\"Type\":5},{\"ID\":\"10030000A656FE5B\",\"Type\":3},{\"ID\":\"User_d03ca514-adfa-4585-a8bd-7182a9a086c7\",\"Type\":2}],\"ActorContextId\":\"2f88f444-62da-4aae-b8af-8331a6915801\",\"InterSystemsId\":\"6d402a5b-c5de-4d9f-a805-9371c109e55f\",\"IntraSystemId\":\"a5568d01-f100-497a-b88b-c9731ff31248\",\"Target\":[{\"ID\":\"User_8f77c311-3ea0-4146-9f7d-db21bd052d3d\",\"Type\":2},{\"ID\":\"mustafa#emumbaa10.onmicrosoft.com\",\"Type\":5},{\"ID\":\"1003BFFDA67CCA03\",\"Type\":3}],\"TargetContextId\":\"2f88f444-62da-4aae-b8af-8331a6915801\"}";
JSONObject send = new JSONObject();
JSONObject input = new JSONObject(received);
// you can add values here and customize the output JSON
send.put("userId", input.getString("UserId"));
send.put("Workload", input.getString("Workload"));
// read Actor list
JSONArray actorArray = input.getJSONArray("Actor");
for (int i = 0; i < actorArray.length(); i++) {
// write your logic here how you want to handle the Actor list
// values
System.out.println(
actorArray.getJSONObject(i).getString("ID") + ":" + actorArray.getJSONObject(i).getInt("Type"));
}
// read ExtendedProperties list
JSONArray extendedProperties = input.getJSONArray("ExtendedProperties");
for (int j = 0; j < extendedProperties.length(); j++) {
// write your logic here how you want to handle the
// ExtendedProperties list values
System.out.println(extendedProperties.getJSONObject(j).getString("Name") + " : "
+ extendedProperties.getJSONObject(j).getString("Value"));
}
System.out.println("*************");
}}

Java - Type Mismatch: Cannot Convert From Element type String[] to List<String>

I'm unfamiliar with getters and setters (and basically just Java) but I have to use them for this assignment, so if I did anything wrong with those please tell me.
The more important issue is the error that I am getting on my method. The word for word instructions from my assignment for the particular method I'm working on are:
Your processData() method should take all the record data from your ArrayList and add the data into each of your instance fields via your setters.
But I keep getting an error that says:
Type mismatch: cannot convert from element type String[] to List
On the line that says "for (List<String> rowData: content)" on the word content.
Thank you very much for any help you can give me.
My code so far:
public abstract class Client {
String file = "bank-Detail.csv";
ArrayList<String[]> bank = new ArrayList<>();
static Client o[] = new Client[12];
public Client(String file) {
this.file = file;
}
private String ID;
private String Age;
private String Sex;
private String Region;
private String Income;
private String Married;
private String Children;
private String Car;
private String Save_Act;
private String Current_Act;
private String Mortgage;
private String Pep;
public List<String[]> readData() throws IOException {
//initialize variable
int count = 0;
//name file
String file = "bank-Detail.txt";
//make array list
List<String[]> content = new ArrayList<>();
//trycatch for exceptions
try {
//file reader
BufferedReader br = new BufferedReader(new FileReader(file));
//string to add lines to
String line = "";
while ((line = br.readLine()) != null) {
content.add(line.split(","));
}
} catch (FileNotFoundException e) {
e.printStackTrace();
}
processData(content);
return content;
}
public String getID() {
return ID;
}
public void setID(String ID) {
this.ID = ID;
}
public String getAge() {
return Age;
}
public void setAge(String age) {
this.Age = age;
}
public String getSex() {
return Sex;
}
public void setSex(String sex) {
Sex = sex;
}
public String getRegion() {
return Region;
}
public void setRegion(String region) {
Region = region;
}
public String getIncome() {
return Income;
}
public void setIncome(String income) {
Income = income;
}
public String getMarried() {
return Married;
}
public void setMarried(String married) {
Married = married;
}
public String getChildren() {
return Children;
}
public void setChildren(String children) {
Children = children;
}
public String getCar() {
return Car;
}
public void setCar(String car) {
Car = car;
}
public String getSave_Act() {
return Save_Act;
}
public void setSave_Act(String save_Act) {
Save_Act = save_Act;
}
public String getCurrent_Act() {
return Current_Act;
}
public void setCurrent_Act(String current_Act) {
this.Current_Act = current_Act;
}
public String getMortgage() {
return Mortgage;
}
public void setMortgage(String mortgage) {
this.Mortgage = mortgage;
}
public String getPep() {
return Pep;
}
public void setPep(String pep) {
Pep = pep;
}
public String toString() {
return "[ID = " + ", age=";
/// ect....
}
public void processData(List<String[]> content) {
int index = 0;
for (List<String> rowData : content) {
//initialize array of objects
//o[index] = new Client();
//use setters to populate your array of objects
o[index].setID(rowData.get(0));
o[index].setAge(rowData.get(1));
o[index].setRegion(rowData.get(3));
o[index].setSex(rowData.get(2));
o[index].setIncome(rowData.get(4));
o[index].setMarried(rowData.get(5));
o[index].setChildren(rowData.get(6));
o[index].setCar(rowData.get(7));
o[index].setSave_Act(rowData.get(8));
o[index].setCurrent_Act(rowData.get(9));
o[index].setMortgage(rowData.get(10));
o[index].setPep(rowData.get(11));
System.out.println(rowData);
index++;
}
}
public void printData() {
}
}
The problem is in the processData method. The type of content is List<String[]>. So when you try to loop this list, each element is a String array, not List. Also, since each element in your list is a String array, you can access the elements of each of the String Array elements of the list by using the normal array square brackets, instead of get method of List. Try the following fix:
public void processData(List<String[]> content) {
int index=0;
for (String[] rowData: content){
//initialize array of objects
//o[index] = new Client();
//use setters to populate your array of objects
o[index].setID(rowData[0]);
o[index].setAge(rowData[1]);
o[index].setRegion(rowData[3]);
o[index].setSex(rowData[2]);
o[index].setIncome(rowData[4]);
o[index].setMarried(rowData[5]);
o[index].setChildren(rowData[6]);
o[index].setCar(rowData[7]);
o[index].setSave_Act(rowData[8]);
o[index].setCurrent_Act(rowData[9]);
o[index].setMortgage(rowData[10]);
o[index].setPep(rowData[11]);
System.out.println(rowData);
index++;
}
}
As your error hints at... content is a List<String[]>, so it contains String[] elements, not List<String> elements.
If your end goal is a list of Client objects, just make the method List<Client> readData() instead.
List<Client> clients = new ArrayList<Client>();
BufferedReader br = null;
try {
//file reader
br = new BufferedReader(new FileReader(file));
//string to add lines to
String line = "";
Client c = null;
while ((line = br.readLine()) != null) {
c = new Client();
String[] rowData = line.split(",");
c.setID(rowData.get(0));
...
clients.add(c);
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} finally {
try {
if (br != null) br.close();
} catch (Exception e) {}
}
return clients;

Parsing JSON in Android, not getting value

I am able to parse everything i need, except for the target_id's in the field_exercis_arc. I get the nid, title and body. Not sure how to get the id's in the field_exercis_arc.
The JSON
[{
"nid": "26",
"title": "Question test",
"body": "xcvxcv",
"field_exercis_arc": ["25","27"]
}]
The Code
String finalJson = buffer.toString();
JSONArray parentArray = new JSONArray(finalJson);
List<ExerciseModel> exerciseModelList = new ArrayList<>();
for(int i=0; i<parentArray.length(); i++){
JSONObject finalObject = parentArray.getJSONObject(i);
title_exi = finalObject.getString("title");
text_exi = finalObject.getString("body");
//This part is working.
ExerciseModel exerciseModel = new ExerciseModel();
exerciseModel.setTitle(finalObject.getString("title"));
exerciseModel.setNid(finalObject.getInt("nid"));
exerciseModel.setBody(finalObject.getString("body"));
//Problem with this part, not getting the target_id's.
List<ExerciseModel.Exer> exerList = new ArrayList<>();
for(int j=0; j<finalObject.getJSONArray("field_exercis_arc").length(); j++){
ExerciseModel.Exer exercis = new ExerciseModel.Exer();
exercis.setTarget_id(finalObject.getJSONArray("field_exercis_arc").getJSONObject(j).getString("target_id"));
exerList.add(exercis);
}
exerciseModel.setExerList(exerList);
exerciseModelList.add(exerciseModel);
mDB.saveRecordEX(exerciseModel);
}
The model for the field_exercis_arc and target_id's fields
private List<Exer> exerList;
public List<Exer> getExerList() {
return exerList;
}
public void setExerList(List<Exer> exerList) {
this.exerList = exerList;
}
public static class Exer{
private String target_id;
public String getTarget_id() {
return target_id;
}
public void setTarget_id(String target_id) {
this.target_id = target_id;
}
}
Thanks in advance
I recommend you to use GSON library to get result from JSON. For that you will need Java class in order to parse result to object. For this you can use JSON to Java Class conversion here.
For you example classes would be:
public class Und
{
private String value;
public String getValue() { return this.value; }
public void setValue(String value) { this.value = value; }
}
public class Body
{
private ArrayList<Und> und;
public ArrayList<Und> getUnd() { return this.und; }
public void setUnd(ArrayList<Und> und) { this.und = und; }
}
public class Und2
{
private String target_id;
public String getTargetId() { return this.target_id; }
public void setTargetId(String target_id) { this.target_id = target_id; }
}
public class FieldExercisArc
{
private ArrayList<Und2> und;
public ArrayList<Und2> getUnd() { return this.und; }
public void setUnd(ArrayList<Und2> und) { this.und = und; }
}
public class RootObject
{
private String vid;
public String getVid() { return this.vid; }
public void setVid(String vid) { this.vid = vid; }
private String uid;
public String getUid() { return this.uid; }
public void setUid(String uid) { this.uid = uid; }
private String title;
public String getTitle() { return this.title; }
public void setTitle(String title) { this.title = title; }
private Body body;
public Body getBody() { return this.body; }
public void setBody(Body body) { this.body = body; }
private FieldExercisArc field_exercis_arc;
public FieldExercisArc getFieldExercisArc() { return this.field_exercis_arc; }
public void setFieldExercisArc(FieldExercisArc field_exercis_arc) { this.field_exercis_arc = field_exercis_arc; }
private String cid;
public String getCid() { return this.cid; }
public void setCid(String cid) { this.cid = cid; }
private String last_comment_timestamp;
public String getLastCommentTimestamp() { return this.last_comment_timestamp; }
public void setLastCommentTimestamp(String last_comment_timestamp) { this.last_comment_timestamp = last_comment_timestamp; }
}
You can convert result to RootObject. Fox example:
String json = "{\"vid\": \"26\",\"uid\": \"1\",\"title\": \"Question test\",\"body\": {\"und\": [{\"value\": \"xcvxcv\"}]},\"field_exercis_arc\": {\"und\": [{\"target_id\": \"25\"},{\"target_id\":\"27\"}]},\"cid\": \"0\",\"last_comment_timestamp\": \"1472217577\"}";
RootObject object = new Gson().fromJson(json, RootObject.class);
System.out.println("Title is: "+object.getTitle() );
Result is:
Title is: Question test
After this you can use your object to get any value from your JSON.
Also you should know that your JSON is not valid. You have commas on two places that should not exists. In string i gave you above those are fixed. You should check you JSON with: JSON Formatter
Use below code :
exercis.setTarget_id(finalObject.getJSONArray("field_exercis_arc").getString(j));
JsonArray fieldArray=yourJsonObject.getJsonArray("field_exercis_arc");
for(int i=0;i<fieldArray.length;i++){
fieldArray.getString(i);
}
TO the parse the JSON you have to do it like this.
String finalJson = buffer.toString();
JSONArray parentArray = new JSONArray(finalJson);
for(int i=0; i<parentArray.length(); i++){
JSONObject finalObject = parentArray.getJSONObject(i);
String title = finalObject.getString("title");
String body = finalObject.getString("body");
JSONArray arr = finalObject.getJSONArray("field_exercis_arc");
for(int x=0; x < arr.length(); x++){
String val = arr.getString(x);
}
}

java.lang.NullPointerException while reading value from json to java object

Here I am reading json value from youtube to java.
I am getting values properly except the thumbnail data while getting thumbnail object value i am getting java.lang.NullPointerException
public class JsonVideoDetais {
public static void main(String... args) {
BufferedReader reader = null;
StringBuilder buffer = null;
try {
String link = "https://gdata.youtube.com/feeds/api/videos/" + "aa_wFClyiVE" + "?v=2&alt=jsonc";
URL url = new URL(link);
reader = new BufferedReader(new InputStreamReader(url.openStream(), "UTF-8"));
buffer = new StringBuilder();
int read;
char[] chars = new char[1024];
while ((read = reader.read(chars)) != -1) {
buffer.append(chars, 0, read);
}
} catch (Exception e) {
} finally {
if (reader != null) {
try {
reader.close();
} catch (IOException ex) {
Logger.getLogger(JsonVideoDetais.class.getName()).log(Level.SEVERE, null, ex);
}
}
}
videoDetails data;
data = new Gson().fromJson(buffer.toString(), videoDetails.class);
System.out.println(data.getData().getTitle());
System.out.println(data.getData().getTn().getHqDefault());
System.out.println(data.getData().getTn().getSqDefault());
}
}
class videoDetails {
private Data data;
public Data getData() {
return data;
}
public void setData(Data data) {
this.data = data;
}
public String toString() {
return String.format("data:%s", data);
}
}
class Data {
private String id;
private String title;
private String description;
private int duration;
private Thumbnail tn;
public Thumbnail getTn() {
return tn;
}
public void setTn(Thumbnail tn) {
this.tn = tn;
}
public int getDuration() {
return duration;
}
public void setDuration(int duration) {
this.duration = duration;
}
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public String getDescription() {
return description;
}
public void setDescription(String description) {
this.description = description;
}
public String toString() {
return String.format("title:%s,id:%s,description:%s,tn:%s,duration:%d", title, id, description, tn, duration);
}
}
class Thumbnail {
private String sqDefault;
private String hqDefault;
public String getSqDefault() {
return sqDefault;
}
public void setSqDefault(String sqDefault) {
this.sqDefault = sqDefault;
}
public String getHqDefault() {
return hqDefault;
}
public void setHqDefault(String hqDefault) {
this.hqDefault = hqDefault;
}
public String toString() {
return String.format("sqDefault:%s,hqDefault:%s", hqDefault, sqDefault);
}
}
I am getting following exception
Exception in thread "main" java.lang.NullPointerException
at utility.JsonVideoDetais.main(JsonVideoDetais.java:52)
while calling
System.out.println(data.getData().getTn().getHqDefault());
System.out.println(data.getData().getTn().getSqDefault());
If you wll see this link. It is having value for sqDefault and hqDefault
I would like to fetch the value of sqDefault and hqDefault.
How to do this.
In your Data class, i created an object like this. I guess the Thumbnail object is getting set to thumbnail, tn is not working on my side too.
private Thumbnail thumbnail;// instead of tn
and the resultant output is : -
Blood Glucose Hindi - Dr. Anup, MD Teaches Series
https://i1.ytimg.com/vi/aa_wFClyiVE/hqdefault.jpg
https://i1.ytimg.com/vi/aa_wFClyiVE/default.jpg
Using debugger to find out which object is null is fastest way to solve your problem.
OR
Find the null return value with the following code:
System.out.println(data);
System.out.println(data.getData());
System.out.println(data.getData().getTn());
--The following text are newly added-----------------
Well, I have run your program on my laptop, and it seem that the json response of https://gdata.youtube.com/feeds/api/videos/aa_wFClyiVE?v=2&alt=jsonc#data/thumbnail/hqDefault contains no tn field at all. That's why you always got null value.

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