I'm very new in spring development because I'm not a back developer.
I create a back to manage sports training.
I has several times a TransactionSystemException like
Exceptionorg.springframework.transaction.TransactionSystemException: Could not commit JPA transaction; nested exception is javax.persistence.RollbackException: Error while committing the transaction
I don't understand what it mean.
I have a class Person who contains a Coordinates object on #OneToOne relation.
Each class have a Service class that has a method of adding.
In PersonService's add method, I call the Coordinates add method which save and return saved object.
This is the add method of PersonClass
public ResponseService<ObjectCreatedModel<UUID, PersonneMorale>> add(PersonneMorale personneMorale) {
String messageErreur = TAG + " - add - ";
StatusReturn status = StatusReturn.ERROR;
String message = null;
ObjectCreatedModel<UUID, PersonneMorale> objectCreatedModel = null;
if (personneMorale != null) {
if (personneMorale.getId() == null) {
personneMorale.setId(UUID.randomUUID());
try {
// Gestion des coordonnees
ResponseService<ObjectCreatedModel<UUID, Coordonnees>> responseServiceCoordonnees =
coordonneesService.add(personneMorale.getCoordonnees());
if (responseServiceCoordonnees.isSuccess() || responseServiceCoordonnees.exist()) {
ResponseService<Coordonnees> responseServiceCoordonneesGet = coordonneesService
.getOne(responseServiceCoordonnees.getObjectReturn().getId());
Coordonnees coordonnees = responseServiceCoordonneesGet.getObjectReturn();
personneMorale.setCoordonnees(coordonnees);
personneMorale = personneMoraleRepository.save(personneMorale);
if (personneMorale != null) {
status = StatusReturn.SUCCESS;
objectCreatedModel = new ObjectCreatedModel<>(personneMorale.getId(), null);
} else {
message = messageErreur + StringResource.E_OCCURRED;
}
} else {
status = responseServiceCoordonnees.getStatusReturn();
message = responseServiceCoordonnees.getMessage();
}
} catch (ConstraintViolationException violationException) {
status = StatusReturn.EXCEPTION;
message = messageErreur + ConstraintViolationReader.extractException(violationException);
} catch (Exception ex) {
status = StatusReturn.EXCEPTION;
message = messageErreur + ex.toString();
}
} else {
message = messageErreur + StringResource.E_MUST_NULL;
}
} else {
message = messageErreur + StringResource.E_SET_PARAMETER;
}
return new ResponseService<>(status, message, objectCreatedModel);
}
This is the add method of CoordinatesService
public ResponseService<ObjectCreatedModel<UUID, Coordonnees>> add(Coordonnees coordonnees) {
StatusReturn status = StatusReturn.ERROR;
String message = "";
ObjectCreatedModel<UUID, Coordonnees> objectCreatedModel = null;
if (coordonnees != null) {
if (coordonnees.getIdCoordonnees() == null) {
try {
coordonnees.setIdCoordonnees(UUID.randomUUID());
Coordonnees coordonneesBase = coordonneesRepository.save(coordonnees);
if (coordonneesBase != null) {
status = StatusReturn.SUCCESS;
objectCreatedModel = new ObjectCreatedModel<>(coordonneesBase.getIdCoordonnees(), null);
} else {
message = StringResource.E_ERROR_OCCURRED;
}
} catch (ConstraintViolationException violationException) {
status = StatusReturn.EXCEPTION;
message = "Exception" + ConstraintViolationReader.extractException(violationException);
} catch (Exception ex) {
status = StatusReturn.EXCEPTION;
message = "Exception" + ex.toString();
}
} else {
message = "Coordonnées" + ErrorsString.ERROR_COMMON_ID_MUST_BE_EMPTY;
}
} else {
message = ErrorsString.ERROR_COORDINATES_MANDATORY;
}
return new ResponseService<>(status, message, objectCreatedModel);
}
The error occurs when CoordinatesService try to save coordinates and pass to the catch (Exception e)
Could you help me to understand what Transaction error mean with an example like my code please ?
I am trying to parse a csv and map the fields to a POJO class. However I can see that the mapping is not achieved correctly.
I am trying to map the header from a POJO file to the csv.
public class CarCSVFileInputBean {
private long Id;
private String shortName;
private String Name;
private String Type;
private String Environment;
//getter and setters
}
Can someone please take a look at my code:
public class carCSVUtil {
private static Log log = LogFactory.getLog(carCSVUtil.class);
private static final List<String> fileHeaderFields = new ArrayList<String>();
private static final String UTF8CHARSET = "UTF-8";
static {
for (Field f : carCSVFileInputBean.class.getDeclaredFields()) {
fileHeaderFields.add(f.getName());
}
}
public static List<carCSVFileInputBean> getCSVInputList(InputStream inputStream) {
CSVReader reader = null;
List<carCSVFileInputBean> csvList = null;
carCSVFileInputBean inputRecord = null;
String[] header = null;
String[] row = null;
try {
reader = new CSVReader(new InputStreamReader(inputStream, UTF8CHARSET));
csvList = new ArrayList<carCSVFileInputBean>();
header = reader.readNext();
boolean isEmptyLine = true;
while ((row = reader.readNext()) != null) {
isEmptyLine = true;
if (!(row.length == 1 && StringUtils.isBlank(row[0]))) { // not an empty line, not even containing ','
inputRecord = new carCSVFileInputBean();
isEmptyLine = populateFields(inputRecord, header, row);
if (!isEmptyLine)
csvList.add(inputRecord);
}
}
} catch (IOException e) {
log.debug("IOException while accessing carCSVFileInputBean: " + e);
return null;
} catch (IllegalAccessException e) {
log.debug("IllegalAccessException while accessing carCSVFileInputBean: " + e);
return null;
} catch (InvocationTargetException e) {
log.debug("InvocationTargetException while copying carCSVFileInputBean properties: " + e);
return null;
} catch (Exception e) {
log.debug("Exception while parsing CSV file: " + e);
return null;
} finally {
try {
if (reader != null)
reader.close();
} catch (IOException ioe) {}
}
return csvList;
}
protected static boolean populateFields(carCSVFileInputBean inputRecord, String[] header, String[] row) throws IllegalAccessException, InvocationTargetException {
boolean isEmptyLine = true;
for (int i = 0; i < row.length; i++) {
String val = row[i];
if (!StringUtils.isBlank(val)) {
BeanUtilsBean.getInstance().copyProperty(inputRecord, header[i], val);
isEmptyLine = false;
}
}
return isEmptyLine;
}
}
I found the solution - the headers in the csv file are expected to begin with a lowercase.
Im trying to read values from my jTable1
private void jcmdOKActionPerformed(java.awt.event.ActionEvent evt) {
DefaultTableModel model = (DefaultTableModel) jTable1.getModel();
int colum=jTable1.getSelectedColumn();
int row=jTable1.getSelectedRow();
System.out.println("row of selected is "+row+"col is "+colum);
final String remark1 = (String) jTable1.getValueAt(row, 8);
final String remark2 = (String) jTable1.getValueAt(row, 9);
final String invoiceno = (String) jTable1.getValueAt(row, 11);
final String id=(String) jTable1.getValueAt(row, 12);
System.out.println(id + "id");
try{
Transaction t = new Transaction(s) {
public Object transact() throws BasicException {
System.out.println("try loop for update");
SentenceExec followinsert = new PreparedSentence(s
, "UPDATE FOLLOWUP SET REMARK1= ?, REMARK2=?, INVOICENO=? WHERE ID= ?"
, SerializerWriteParams.INSTANCE);
followinsert.exec(new DataParams() { public void writeValues() throws BasicException {
System.out.println("executing command");
setString(1, remark1);
setString(2, remark2);
setString(3, invoiceno);
setString(2, id);
//System.out.println(" after update line");
}});
return null;
}
};
t.execute(); //im getting null pointer exception here :(
}
catch (BasicException ex) {
Logger.getLogger(FollowUp.class.getName()).log(Level.SEVERE, null, ex);
}
}
i get this error:
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at com.openbravo.data.loader.Transaction.execute(Transaction.java:42)
at com.openbravo.pos.followup.FollowUp.jcmdOKActionPerformed(FollowUp.java:679)
at com.openbravo.pos.followup.FollowUp.access$300(FollowUp.java:66)
at com.openbravo.pos.followup.FollowUp$5.actionPerformed(FollowUp.java:193)
Transaction.java is
public abstract class Transaction<T> {
private Session s;
/** Creates a new instance of Transaction */
public Transaction(Session s) {
this.s = s;
}
public final T execute() throws BasicException {
if (s.isTransaction()) {
return transact();
} else {
try {
try {
s.begin();
T result = transact();
s.commit();
return result;
} catch (BasicException e) {
s.rollback();
throw e;
}
} catch (SQLException eSQL) {
throw new BasicException("Transaction error", eSQL);
}
}
}
protected abstract T transact() throws BasicException;
}
This is the first version of my code :
public class ListSchedule implements ListInterface {
private ArrayList<Schedule> list;
private String cookie;
public ListSchedule() {
this.list = new ArrayList<Schedule>();
}
public ArrayList<Schedule> getList() {
return list;
}
}
In another class, I made this call :
protected final ListSchedule parse(String jsonString)
throws CustomException {
ListSchedule list = new ListSchedule();
JSONArray schedulesArray;
try {
// Convert the response to a JSONObject
JSONObject json = new JSONObject(jsonString);
try {
int errorCode = json.getInt("error");
// Check if there is no error from FilBleu server
if (errorCode > 0) {
throw new CustomException(
CustomException.ERROR_FILBLEU,
"DataAccessObject", "Server error "
+ json.getInt("subError"));
}
try {
String cookie = json.getString("cookie");
list = new ListSchedule(cookie);
} catch (JSONException e) {
throw new CustomException(CustomException.JSON_FORMAT,
"DataAccessObject", "No cookie value");
}
schedulesArray = json.getJSONArray("schedules");
// NullPointerException with the line below
Log.d("DAO", list.getList().toString());
parseSchedulesArray(list, schedulesArray);
} catch (JSONException e) { // Unable to get the error code
throw new CustomException(CustomException.JSON_FORMAT,
"DataAccessObject", "Bad JSON format ("
+ e.getMessage() + ")");
}
} catch (JSONException e) { // Unable to convert response
throw new CustomException(CustomException.JSON_FORMAT,
"DataAccessObject", "Bad JSON format ("
+ e.getMessage() + ")");
}
return list;
}
then I had a NullPointerException from the line Log.d("DAO", list.getList().toString());. So I tried another solution. As you can see, the only difference is the initialization of the list property :
public class ListSchedule implements ListInterface {
private ArrayList<Schedule> list = new ArrayList<Schedule>();
private String cookie;
public ListSchedule() {
}
public ArrayList<Schedule> getList() {
return list;
}
}
and the NullPointerException was never thrown again...
I don't really understand the difference between the two ways of initializing the list property. Can somebody give me a hint please ?
I am speculating that the following constructor exists in your code base :
public ListSchedule(String cookie) {
this.cookie = cookie;
}
and what you need is the following:
public ListSchedule(String cookie) {
this.cookie = cookie;
this.list = new ArrayList<Schedule>();
}
This is further validated by the invocation of this line in your program:
list = new ListSchedule(cookie);
Notice how you don't initialize the list in the second constructor. Also you start by invoking the default constructor, but you later reassign the pointer to the object into what gets created from the String constructor of ListSchedule.
You code is calling this constructor:
list = new ListSchedule(cookie);
Which to me, does not call the one that initializes your ArrayList<Schedule> and that explains the NullReferenceException
I want to write a Object into CSV file.
For XML we have XStream like this
So if i want to convert object to CSV do we have any such library ?
EDIT:
I want to pass my list of Bean to a method which should write all the fields of bean to CSV.
First, serialization is writing the object to a file 'as it is'. AFAIK, you cannot choose file formats and all. The serialized object (in a file) has its own 'file format'
If you want to write the contents of an object (or a list of objects) to a CSV file, you can do it yourself, it should not be complex.
Looks like Java CSV Library can do this, but I have not tried this myself.
EDIT: See following sample. This is by no way foolproof, but you can build on this.
//European countries use ";" as
//CSV separator because "," is their digit separator
private static final String CSV_SEPARATOR = ",";
private static void writeToCSV(ArrayList<Product> productList)
{
try
{
BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(new FileOutputStream("products.csv"), "UTF-8"));
for (Product product : productList)
{
StringBuffer oneLine = new StringBuffer();
oneLine.append(product.getId() <=0 ? "" : product.getId());
oneLine.append(CSV_SEPARATOR);
oneLine.append(product.getName().trim().length() == 0? "" : product.getName());
oneLine.append(CSV_SEPARATOR);
oneLine.append(product.getCostPrice() < 0 ? "" : product.getCostPrice());
oneLine.append(CSV_SEPARATOR);
oneLine.append(product.isVatApplicable() ? "Yes" : "No");
bw.write(oneLine.toString());
bw.newLine();
}
bw.flush();
bw.close();
}
catch (UnsupportedEncodingException e) {}
catch (FileNotFoundException e){}
catch (IOException e){}
}
This is product (getters and setters hidden for readability):
class Product
{
private long id;
private String name;
private double costPrice;
private boolean vatApplicable;
}
And this is how I tested:
public static void main(String[] args)
{
ArrayList<Product> productList = new ArrayList<Product>();
productList.add(new Product(1, "Pen", 2.00, false));
productList.add(new Product(2, "TV", 300, true));
productList.add(new Product(3, "iPhone", 500, true));
writeToCSV(productList);
}
Hope this helps.
Cheers.
For easy CSV access, there is a library called OpenCSV. It really ease access to CSV file content.
EDIT
According to your update, I consider all previous replies as incorrect (due to their low-levelness). You can then go a completely diffferent way, the hibernate way, in fact !
By using the CsvJdbc driver, you can load your CSV files as JDBC data source, and then directly map your beans to this datasource.
I would have talked to you about CSVObjects, but as the site seems broken, I fear the lib is unavailable nowadays.
Two options I just ran into:
http://sojo.sourceforge.net/
http://supercsv.sourceforge.net/
It would be interesting to have a csv serializer as it would take up the minimal space compared to other serializing method.
The closest support for java object to csv is stringutils provided by spring utils project
arrayToCommaDelimitedString(Object[] arr) but it is far from being a serializer.
Here is a simple utility which uses reflection to serialize value objects
public class CSVWriter
{
private static String produceCsvData(Object[] data) throws IllegalArgumentException, IllegalAccessException, InvocationTargetException
{
if(data.length==0)
{
return "";
}
Class classType = data[0].getClass();
StringBuilder builder = new StringBuilder();
Method[] methods = classType.getDeclaredMethods();
for(Method m : methods)
{
if(m.getParameterTypes().length==0)
{
if(m.getName().startsWith("get"))
{
builder.append(m.getName().substring(3)).append(',');
}
else if(m.getName().startsWith("is"))
{
builder.append(m.getName().substring(2)).append(',');
}
}
}
builder.deleteCharAt(builder.length()-1);
builder.append('\n');
for(Object d : data)
{
for(Method m : methods)
{
if(m.getParameterTypes().length==0)
{
if(m.getName().startsWith("get") || m.getName().startsWith("is"))
{
System.out.println(m.invoke(d).toString());
builder.append(m.invoke(d).toString()).append(',');
}
}
}
builder.append('\n');
}
builder.deleteCharAt(builder.length()-1);
return builder.toString();
}
public static boolean generateCSV(File csvFileName,Object[] data)
{
FileWriter fw = null;
try
{
fw = new FileWriter(csvFileName);
if(!csvFileName.exists())
csvFileName.createNewFile();
fw.write(produceCsvData(data));
fw.flush();
}
catch(Exception e)
{
System.out.println("Error while generating csv from data. Error message : " + e.getMessage());
e.printStackTrace();
return false;
}
finally
{
if(fw!=null)
{
try
{
fw.close();
}
catch(Exception e)
{
}
fw=null;
}
}
return true;
}
}
Here is an example value object
public class Product {
private String name;
private double price;
private int identifier;
private boolean isVatApplicable;
public Product(String name, double price, int identifier,
boolean isVatApplicable) {
super();
this.name = name;
this.price = price;
this.identifier = identifier;
this.isVatApplicable = isVatApplicable;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public double getPrice() {
return price;
}
public void setPrice(long price) {
this.price = price;
}
public int getIdentifier() {
return identifier;
}
public void setIdentifier(int identifier) {
this.identifier = identifier;
}
public boolean isVatApplicable() {
return isVatApplicable;
}
public void setVatApplicable(boolean isVatApplicable) {
this.isVatApplicable = isVatApplicable;
}
}
and the code to run the util
public class TestCSV
{
public static void main(String... a)
{
Product[] list = new Product[5];
list[0] = new Product("dvd", 24.99, 967, true);
list[1] = new Product("pen", 4.99, 162, false);
list[2] = new Product("ipad", 624.99, 234, true);
list[3] = new Product("crayons", 4.99,127, false);
list[4] = new Product("laptop", 1444.99, 997, true);
CSVWriter.generateCSV(new File("C:\\products.csv"),list);
}
}
Output:
Name VatApplicable Price Identifier
dvd true 24.99 967
pen false 4.99 162
ipad true 624.99 234
crayons false 4.99 127
laptop true 1444.99 997
I wrote a simple class that uses OpenCSV and has two static public methods.
static public File toCSVFile(Object object, String path, String name) {
File pathFile = new File(path);
pathFile.mkdirs();
File returnFile = new File(path + name);
try {
CSVWriter writer = new CSVWriter(new FileWriter(returnFile));
writer.writeNext(new String[]{"Member Name in Code", "Stored Value", "Type of Value"});
for (Field field : object.getClass().getDeclaredFields()) {
writer.writeNext(new String[]{field.getName(), field.get(object).toString(), field.getType().getName()});
}
writer.flush();
writer.close();
return returnFile;
} catch (IOException e) {
Log.e("EasyStorage", "Easy Storage toCSVFile failed.", e);
return null;
} catch (IllegalAccessException e) {
Log.e("EasyStorage", "Easy Storage toCSVFile failed.", e);
return null;
}
}
static public void fromCSVFile(Object object, File file) {
try {
CSVReader reader = new CSVReader(new FileReader(file));
String[] nextLine = reader.readNext(); // Ignore the first line.
while ((nextLine = reader.readNext()) != null) {
if (nextLine.length >= 2) {
try {
Field field = object.getClass().getDeclaredField(nextLine[0]);
Class<?> rClass = field.getType();
if (rClass == String.class) {
field.set(object, nextLine[1]);
} else if (rClass == int.class) {
field.set(object, Integer.parseInt(nextLine[1]));
} else if (rClass == boolean.class) {
field.set(object, Boolean.parseBoolean(nextLine[1]));
} else if (rClass == float.class) {
field.set(object, Float.parseFloat(nextLine[1]));
} else if (rClass == long.class) {
field.set(object, Long.parseLong(nextLine[1]));
} else if (rClass == short.class) {
field.set(object, Short.parseShort(nextLine[1]));
} else if (rClass == double.class) {
field.set(object, Double.parseDouble(nextLine[1]));
} else if (rClass == byte.class) {
field.set(object, Byte.parseByte(nextLine[1]));
} else if (rClass == char.class) {
field.set(object, nextLine[1].charAt(0));
} else {
Log.e("EasyStorage", "Easy Storage doesn't yet support extracting " + rClass.getSimpleName() + " from CSV files.");
}
} catch (NoSuchFieldException e) {
Log.e("EasyStorage", "Easy Storage fromCSVFile failed.", e);
} catch (IllegalAccessException e) {
Log.e("EasyStorage", "Easy Storage fromCSVFile failed.", e);
}
} // Close if (nextLine.length >= 2)
} // Close while ((nextLine = reader.readNext()) != null)
} catch (FileNotFoundException e) {
Log.e("EasyStorage", "Easy Storage fromCSVFile failed.", e);
} catch (IOException e) {
Log.e("EasyStorage", "Easy Storage fromCSVFile failed.", e);
} catch (IllegalArgumentException e) {
Log.e("EasyStorage", "Easy Storage fromCSVFile failed.", e);
}
}
I think with some simple recursion these methods could be modified to handle any Java object, but for me this was adequate.
Though its very late reply, I have faced this problem of exporting java entites to CSV, EXCEL etc in various projects, Where we need to provide export feature on UI.
I have created my own light weight framework. It works with any Java Beans, You just need to add annotations on fields you want to export to CSV, Excel etc.
Link: https://github.com/abhisoni96/dev-tools
Worth mentioning that the handlebar library https://github.com/jknack/handlebars.java can trivialize many transformation tasks include toCSV.
You can use gererics to work for any class
public class FileUtils<T> {
public String createReport(String filePath, List<T> t) {
if (t.isEmpty()) {
return null;
}
List<String> reportData = new ArrayList<String>();
addDataToReport(t.get(0), reportData, 0);
for (T k : t) {
addDataToReport(k, reportData, 1);
}
return !dumpReport(filePath, reportData) ? null : filePath;
}
public static Boolean dumpReport(String filePath, List<String> lines) {
Boolean isFileCreated = false;
String[] dirs = filePath.split(File.separator);
String baseDir = "";
for (int i = 0; i < dirs.length - 1; i++) {
baseDir += " " + dirs[i];
}
baseDir = baseDir.replace(" ", "/");
File base = new File(baseDir);
base.mkdirs();
File file = new File(filePath);
try {
if (!file.exists())
file.createNewFile();
} catch (Exception e) {
e.printStackTrace();
return isFileCreated;
}
try (BufferedWriter writer = new BufferedWriter(
new OutputStreamWriter(new FileOutputStream(file), System.getProperty("file.encoding")))) {
for (String line : lines) {
writer.write(line + System.lineSeparator());
}
} catch (IOException e) {
e.printStackTrace();
return false;
}
return true;
}
void addDataToReport(T t, List<String> reportData, int index) {
String[] jsonObjectAsArray = new Gson().toJson(t).replace("{", "").replace("}", "").split(",\"");
StringBuilder row = new StringBuilder();
for (int i = 0; i < jsonObjectAsArray.length; i++) {
String str = jsonObjectAsArray[i];
str = str.replaceFirst(":", "_").split("_")[index];
if (i == 0) {
if (str != null) {
row.append(str.replace("\"", ""));
} else {
row.append("N/A");
}
} else {
if (str != null) {
row.append(", " + str.replace("\"", ""));
} else {
row.append(", N/A");
}
}
}
reportData.add(row.toString());
}