I am trying to create a simple little webservice on a glassfish server backed by a mysql server on my netbeans
Its designed to be a very simple currency conversion service
Here is what its supposed to do
It takes an amount of money (Always in GBp) as an INT and a currency to convert it in as a string.
The service then looks up that currency from my database table to get the conversion rate with a query like
select * from exchange.rates where currency = string
Then it performs the simple calculation to convert the money into the currency and returns the amount
The problem is that i have no clue how to call that conversion rate from my mysql server, i tried and tried but nothing happens
i just keep getting the same amount i entered in.
I tried entering euro and 10
I set the rate for that in my database but i just got 10 back out when i tested the webservice
/**
* Web service operation
*/
#WebMethod(operationName = "convert")
public int convert(#WebParam(name = "currency") String currency, #WebParam(name = "amount") int amount) {
int newamount = 0;
try {
Class.forName("com.mysql.jdbc.Driver");
Connection con =
DriverManager.getConnection("jdbc:mysql://localhost:3306/exhange",
"root", "25587");
PreparedStatement st =
con.prepareStatement("select * from rates where currency = '" + currency+"'");
ResultSet rs = null;
rs = st.executeQuery();
rs.first();
newamount =rs.getInt("conversion") * amount;
return newamount;
} catch (Exception e) {
System.out.println("error");
}
return amount;
}
Whe you use prepared statemen you need to pass the parameter explicitly:
PreparedStatement st = con.prepareStatement("select * from rates where currency = ?");
st.setString(1,currency) //Check this
ResultSet rs = st.executeQuery();
// If you are sure that is only one row then you nee to do
String columnX = null;
if (rs.next() != null) {
columnX = rs.getString(1); //Where 1 is the first column
}
Related
Hello so i'm trying to code my own type of error catching on a sql statement. On my method add order i want to add some way of stopping someone from selling a product which has no stock. My code below does not yet do that. I can add orders and update the stock amount but i haven't figured out a way of adding an if statement that works.
#FXML
public void AddOrder(ActionEvent event) {
String orderID = orderBox.getText();
String customerID = customerBox.getText();
String productID = productBox.getText();
String amount = amountBox.getText();
// String cost = costBox.getText();
String date = dateBox.getText();
PreparedStatement sample;
dc = new Database();
try {
c = dc.Connect();
sample = c.prepareStatement("Select stockAmount from inventory WHERE productID = ?");
ResultSet rs = sample.executeQuery();
while (rs.next()) {
Integer amount2 = rs.getInt("Amount");
if (amount2 <= 0) {
System.out.println("No stock exists");
} else {
query = c.prepareStatement(
"INSERT INTO ordertable (orderID,customerID,productID,Amount,Date)VALUES(?,?,?,?,?)");
update = c.prepareStatement("UPDATE inventory set stockAmount = stockAmount-? WHERE productID =?");
update.setString(1, amount);
update.setString(2, productID);
update.execute();
query.setString(1, orderID);
query.setString(2, customerID);
query.setString(3, productID);
query.setString(4, amount);
// query.setString(5, cost);
query.setString(5, date);
query.executeUpdate();
// update.executeUpdate();
Alert confirmation = new Alert(Alert.AlertType.CONFIRMATION, "Saved");
// closeConfirmation.showMessageDialog(this, "Saved");
confirmation.show();
}
}
} catch (Exception e) {
e.printStackTrace();
}
orderBox.clear();
customerBox.clear();
productBox.clear();
amountBox.clear();
dateBox.clear();
loadDataFromDatabase(event);
}
Below is the error i'm getting
java.sql.SQLException: No value specified for parameter 1
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:964)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:897)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:886)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:860)
at
If you are just having trouble because of that exception, check these lines:
sample = c.prepareStatement("Select stockAmount from inventory WHERE productID = ?");
ResultSet rs = sample.executeQuery();
The query is defined to accept a parameter for productID, but you haven't given it a value prior to executing the statement. You'll need to change the query so that it doesn't require a parameter or assign a value to the parameter, like this:
sample = c.prepareStatement("Select stockAmount from inventory WHERE productID = ?");
sample.setString(1, productID);
ResultSet rs = sample.executeQuery();
I am trying to return a tuples within a certain year and I can't get the prepared statement to return anything but an empty set. Here is the parameter I call it with: year.valueOf("2014-01-01"); not sure if that's already the problem, and this is just for testing it's normally a value from a textfield.
public List<Sales> findYear(Date date) {
try {
List<Sales> listSales = new ArrayList<>();
I tried it with two parameters so this is just the test version.
When I hard code both dates into the prepared statement it works, so the method itself seems fine. Adding ' ' around the ? makes no difference.
PreparedStatement ps = ConnectDB
.getConnection()
.prepareStatement(
"select * from sales where sale_date between ? and '2014-12-30'");
ps.setDate(1, date);
ResultSet rs = ps.executeQuery();
while (rs.next()) {
Sales s = new Sales();
s.setEmpno(rs.getInt("empno"));
s.setOutno(rs.getInt("outno"));
s.setPno(rs.getInt("pno"));
s.setCno(rs.getInt("cno"));
s.setOno(rs.getInt("ono"));
s.setQty(rs.getInt("qty"));
s.setSale_date(rs.getDate("sale_date"));
s.setSale_time(rs.getTime("sale_time"));
listSales.add(s);
}
return listSales;
} catch (Exception e) {
System.out.println(e.getMessage());
return null;
}
}
"select * from sales where sale_date between ?-?-? and ?-?-?"
Then set the dates:
prepare.setInt(1, day1);
prepare.setInt(2, month1);
prepare.setInt(3, year1);
prepare.setInt(4, day2);
prepare.setInt(5, month2);
prepare.setInt(6, year3);
You can also turn a date into a string:
"select * from sales where sale_date between ? and ?"
...
String date1Str = SimpleDateFormat("dd-MM-yyyy").format(date1);
String date2Str = SimpleDateFormat("dd-MM-yyyy").format(date2);
prepare.setString(1, date1Str);
prepare.setString(2, date2Str);
Expanded example:
try {
PreparedStatement ps = ConnectDB.getConnection()
.prepareStatement(
"select * from sales where sale_date between ? and ?");
ps.setDate(1, date);
// whatever date2 is
ps.setDate(2, date2);
ResultSet rs = ps.executeQuery();
while (rs.next()) {
Sales s = new Sales();
s.setEmpno(rs.getInt("empno"));
s.setOutno(rs.getInt("outno"));
s.setPno(rs.getInt("pno"));
s.setCno(rs.getInt("cno"));
s.setOno(rs.getInt("ono"));
s.setQty(rs.getInt("qty"));
s.setSale_date(rs.getDate("sale_date"));
s.setSale_time(rs.getTime("sale_time"));
listSales.add(s);
}
return listSales;
} catch (Exception e) {
System.out.println(e.getMessage());
return null;
}
I have
employee(id, name, company, salary);
Need to display data for given id
public static void Connect(String conString, String username, String password, int id) throws SQLException{
try {
Class.forName("com.mysql.jdbc.Driver");
Connection conn = null;
conn = DriverManager.getConnection(conString, username, password);
String query = "select * from employee where id = " + id + "" ;
ResultSet rs = null;
Statement stmt = null;
stmt = conn.createStatement();
rs = stmt.executeQuery(query);
while(rs.next()){
String name = rs.getString("name");
String company = rs.getString("company");
int salary = rs.getInt("salary");
System.out.println("Name: " + name + "\tCompany: " + company + "\tSalary: " + salary);
}
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
But here we are passing the id directly. How can we pass it like parametrized queries (like how we pass ? during PreparedStatement)
in that case your query should be
String query = "select * from employee where id = ?";
instead of Statement you need to create PreparedStatement
PreparedStatement preparedStatement = conn.prepareStatement(query);
and then set your id to the prepared statement
preparedStatment.setInt(1, id);
finally execute the query
resultSet = preparedStatement.executeQuery();
It's old post but I would still like to add my answer.
I don't have enough reputation to comment on #prasad's answer, so I am adding small correction as separate answer. Actually, passing query inside praparedStatement.executeQuery() throws MySQLSyntaxErrorException because still it calls Statement.executeQuery instead of PreparedStatement.executeQuery(). And how do I know? I had to spent ample amount of time in figuring out this issue.
So use PreparedStatement.executeQuery() instead of PreparedStament.executeQuery(query).
I have a method that returns an array list of search results from my database.
Instead of:
Select *
from employee
where first_name like ?
I would rather use:
Select *
from employee
where ? like ?
but I'm not sure if this is even possible? there's no errors when I compile it in eclipse but it keeps giving me blank values in the array. Is there something I'm doing wrong?
This is the method that gives me the blank value it works fine when I have where first_name like ? so I know the logic works.
public static ArrayList<String> AdvanceSearchFirstName(String selected, String searchTerm) {
String selectQuery = "select * from employee_info where ? like ?";
ArrayList<String> searchResults = new ArrayList<>();
try {
stmt = con.createStatement();
PreparedStatement ps = con.prepareStatement(selectQuery);
ps.setString(1, selected);
ps.setString(2, '%'+searchTerm+'%');
ResultSet rs = ps.executeQuery();
while (rs.next()) {
String firstName = rs.getString("first_name");
String lastName = rs.getString("last_name");
String studentNumber = rs.getString("employee_number");
String combo = employeeNumber + " " + firstName + " " + lastName;
searchResults.add(combo);
}
} catch (SQLException e) {
e.printStackTrace();
}
return searchResults;
}
I've looked over a lot of posts so I'm pretty sure this hasn't been posted but I apologies if this is a double. I'm new to programming and sql so any help is appreciated.
I have an error updating my database because of variables. This is my code:
UPDATE `payment` SET `paid`=1 AND `amoun`=$amountpaid WHERE `paid`=0 AND `userid`=$uid
$amountpaid is the amount of the bill that the user paid and $uid is user id. It seems like using $ in front of variable names is forbidden. How can I use variables in SQL?
Where are your variables coming from? You probably want something like this if you're using JDBC:
int setPaid = 1;
int amountPaid = x; // put $amountpaid here
int wherePaid = 0;
int userId = y; // put $uid here
String updateQuery = "UPDATE payment SET paid = ?, amoun = ?"
+ " WHERE paid = ? AND userid = ?";
PreparedStatement ps = con.prepareStatement(updateQuery);
ps.setInt(1, setPaid);
ps.setInt(2, amountPaid);
ps.setInt(3, wherePaid);
ps.setInt(4, userId);
ps.executeUpdate();
I got the solution by using String.
I converted the ArrayList to a String and then sent the data as string. The data got updated but I don't know what will happen next if I want to view the data in the client tier...