A presentation about Developing Applications with MySQL and Java for beginners. It includes the following topics: - Requirements - MySQL Data Definitions - Java Classes - MySQL Connector (JDBC) - Define Methods - Compile and Run

1. Saeid Zebardast
@saeid
http://about.me/saeid
saeid.zebardast@gmail.com
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2. Please Please Please
Ask Questions
As Much As You Like
• This is not a lecture!
- But an opportunity to learn
from each other.
- If you haven’t seen some of
these frameworks, methods,
etc. It is OK!
- Let we know if you know
‣ Better ways
‣ Best practices
‣ My mistakes!

3. Requirements
• Java (OpenJDK)
• MySQL
• MySQL Connector
- JDBC (Java Database Connectivity)
‣ https://dev.mysql.com/downloads/connector/j/
• Text Editor
• Command Line!
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4. MySQL Data Definition
• Create database
- $ mysql -u root -p
‣ mysql> CREATE DATABASE phonebook_app;
• Create database user
- $ mysql -u root -p
‣ mysql> GRANT ALL PRIVILEGES on `phonebook_app`.* to `pb_app`@'127.0.0.1' identified by '123456';
• Create table
- $ mysql -u pb_app -p phonebook_app
‣ mysql> CREATE TABLE `contact` (
`id` INT(11) UNSIGNED NOT NULL AUTO_INCREMENT,
`first_name` VARCHAR(100),
`last_name` VARCHAR(100),
`email` VARCHAR(100),
`mobile` VARCHAR(15),
PRIMARY KEY (`id`)
);
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5. Java Classes
Contact
• Contact
- Fields
‣ long id
‣ String firstName
‣ String lastName
‣ String email
‣ String mobile
- Methods
‣ Contact()
‣ Getters for all fields: getId(), getFirstName() and etc.
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6. Java Classes
PhonebookApp
• PhonebookApp
- Import java.sql.* and java.util.*;
- Fields
‣ Connection con;
‣ PreparedStatement pst;
‣ ResultSet rs;
‣ String url;
‣ String user;
‣ String password;
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- Methods
‣ PhonebookApp()
‣ main()
‣ printHelp()
‣ showList()
‣ add()
‣ delete()
‣ closeAllConnections()

7. Create Content Class
public class Contact {
private long id;
private String firstName;
private String lastName;
private String email;
private String mobile;
Contact(long id, String firstName, String lastName, String email, String mobile) {
this.id = id;
this.firstName = firstName;
this.lastName = lastName;
this.email = email;
this.mobile = mobile;
}
// getter here
}
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8. Create PhonebookApp Class
Fields and Constructor
public class PhonebookApp {
Connection con;
PreparedStatement pst;
ResultSet rs;
String url;
String user;
String password;
PhonebookApp() {
url = "jdbc:mysql://127.0.0.1:3306/phonebook_app";
user = "pb_app";
password = "123456";
}
//write methods here
}
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9. Create PhonebookApp Class
Methods: main()
public static void main(String[] args) {
if (args == null || args.length == 0) {
printHelp();
return;
}
PhonebookApp phonebookApp = new PhonebookApp();
switch (args[0]) {
case "list" : phonebookApp.showList(); break;
case "add" : phonebookApp.add(args); break;
case "delete" : phonebookApp.delete(args); break;
default : printHelp();
}
}
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10. Create PhonebookApp Class
Methods: printHelp()
static void printHelp() {
System.out.println("Usage: java PhonebookApp [OPTIONS]");
System.out.println("Options: add FIRST_NAME LAST_NAME EMAIL MOBILE");
System.out.println("Options: list");
System.out.println("Options: delete ID”);
}
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11. Create PhonebookApp Class
Methods: showList()
void showList() {
List<Contact> contactList = new ArrayList<>();
try {
con = DriverManager.getConnection(url, user, password);
pst = con.prepareStatement("SELECT * FROM contact");
rs = pst.executeQuery();
while (rs.next()) {
contactList.add(new Contact(rs.getLong("id"), rs.getString("first_name"), rs.getString("last_name"),
rs.getString("email"), rs.getString("mobile")));
}
if (contactList.size() > 0) {
for (Contact contact : contactList) {
System.out.println(contact.getId() + "-" + contact.getFirstName() + " " + contact.getLastName() + ": Email = '" +
contact.getEmail() + "', Mobile = '" + contact.getMobile() + "'.");
}
} else {
System.out.println("You don't have any contacts in your list!");
}
} catch (SQLException ex) {
Logger lgr = Logger.getLogger(this.getClass().getName());
lgr.log(Level.SEVERE, ex.getMessage(), ex);
} finally {
closeAllConnections();
}
}
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12. Create PhonebookApp Class
Methods: add()
void add(String[] args) {
if (args.length != 5) {
System.out.println("Error: Wrong Usage!");
printHelp();
} else {
try {
con = DriverManager.getConnection(url, user, password);
pst = con.prepareStatement("INSERT INTO contact(first_name, last_name, email, mobile) value (?,?,?,?) ");
int index = 1;
pst.setString(index, args[index++]);
pst.setString(index, args[index++]);
pst.setString(index, args[index++]);
pst.setString(index, args[index++]);
pst.executeUpdate();
} catch (SQLException ex) {
Logger lgr = Logger.getLogger(this.getClass().getName());
lgr.log(Level.SEVERE, ex.getMessage(), ex);
} finally {
closeAllConnections();
}
}
}
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13. Create PhonebookApp Class
Methods: delete()
void delete(String[] args) {
if (args.length != 2) {
System.out.println("Error: Wrong Usage!");
printHelp();
} else {
long id = Integer.parseInt(args[1]);
if (id < 1) {
System.out.println("Error: id is not valid!");
} else {
try {
con = DriverManager.getConnection(url, user, password);
pst = con.prepareStatement("DELETE FROM contact where id = ? ");
pst.setLong(1, id);
pst.executeUpdate();
} catch (SQLException ex) {
Logger lgr = Logger.getLogger(this.getClass().getName());
lgr.log(Level.SEVERE, ex.getMessage(), ex);
} finally {
closeAllConnections();
}
}
}
}
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14. Create PhonebookApp Class
Methods: closeAllConnections()
void closeAllConnections() {
try {
if (rs != null) {
rs.close();
}
if (pst != null) {
pst.close();
}
if (con != null) {
con.close();
}
} catch (SQLException ex) {
Logger lgr = Logger.getLogger(this.getClass().getName());
lgr.log(Level.WARNING, ex.getMessage(), ex);
}
}
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15. Compile and Run
PhonebookApp
• compile
- javac PhonebookApp.java
• run
- java -cp .:lib/mysql-connector-java-5.1.34-bin.jar PhonebookApp
- java -cp .:lib/mysql-connector-java-5.1.34-bin.jar PhonebookApp list
- java -cp .:lib/mysql-connector-java-5.1.34-bin.jar PhonebookApp add
myFirstName myLastName myEmail myMobile
- java -cp .:lib/mysql-connector-java-5.1.34-bin.jar PhonebookApp delete 2
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16. Read The F* Manual
• RTFM
- https://dev.mysql.com/doc/
- http://docs.oracle.com/javase/
• Java: The Really Big Index
- http://docs.oracle.com/javase/tutorial/reallybigindex.html
• MySQL Help
- mysql> HELP;
- mysql> HELP CONTENTS;
- mysql> HELP SELECT;
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17. Thank You