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Appendix B. AccountService Example
Abstract
The
AccountService example class illustrates how you can use Spring JdbcTemplate class to access a JDBC data source.
B.1. AccountService Example Code
Overview
The
AccountService class provides a simple example of accessing a data source through JDBC. The methods in this class can be used inside a local transaction or inside a global (XA) transaction.
Database schema
The
AccountService example requires a single database table, accounts, which has two columns: a name column (containing the account name), and an amount column (containing the dollar balance of the account). The required database schema can be created by the following SQL statement:
CREATE TABLE accounts (name VARCHAR(50), amount INT);
AccountService class
Example B.1, “The AccountService Class” shows the complete listing of the
AccountService class, which uses the Spring JdbcTemplate class to access a JDBC data source.
Example B.1. The AccountService Class
// Java
package org.fusesource.example.tx.xa;
import java.util.List;
import javax.sql.DataSource;
import org.apache.camel.Exchange;
import org.apache.camel.language.XPath;
import org.apache.log4j.Logger;
import org.springframework.jdbc.core.JdbcTemplate;
public class AccountService {
private static Logger log = Logger.getLogger(AccountService.class);
private JdbcTemplate jdbc;
public AccountService() {
}
public void setDataSource(DataSource ds) {
jdbc = new JdbcTemplate(ds);
}
public void credit(
@XPath("/transaction/transfer/receiver/text()") String name,
@XPath("/transaction/transfer/amount/text()") String amount
)
{
log.info("credit() called with args name = " + name + " and amount = " + amount);
int origAmount = jdbc.queryForInt(
"select amount from accounts where name = ?",
new Object[]{name}
);
int newAmount = origAmount + Integer.parseInt(amount);
jdbc.update(
"update accounts set amount = ? where name = ?",
new Object[] {newAmount, name}
);
}
public void debit(
@XPath("/transaction/transfer/sender/text()") String name,
@XPath("/transaction/transfer/amount/text()") String amount
)
{
log.info("debit() called with args name = " + name + " and amount = " + amount);
int iamount = Integer.parseInt(amount);
if (iamount > 100) {
throw new IllegalArgumentException("Debit limit is 100");
}
int origAmount = jdbc.queryForInt(
"select amount from accounts where name = ?",
new Object[]{name}
);
int newAmount = origAmount - Integer.parseInt(amount);
if (newAmount < 0) {
throw new IllegalArgumentException("Not enough in account");
}
jdbc.update(
"update accounts set amount = ? where name = ?",
new Object[] {newAmount, name}
);
}
public void dumpTable(Exchange ex) {
log.info("dump() called");
List<?> dump = jdbc.queryForList("select * from accounts");
ex.getIn().setBody(dump.toString());
}
}