好吧我是java的新手,我不知道如何真正做到这一点。如果你们能帮助我,那么我可能会理解更多。我得到了我的主类(Mysql.java)和一个Connection类(Connection.java)现在我希望它使用Connection.java部分连接到数据库。但我想从Mysql.java中使用它。我现在明白了:
Mysql.java
public class Mysql {
public static void main(String[] args) {
Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
int w = screenSize.width;
JFrame frame = new MainFrame(w/5, 100, 2*w/5, 0);
frame.show();
new Connection();
}
}
class MainFrame extends JFrame {
MainFrame(int width, int height, int x, int y) {
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setTitle("Todothelydoo - To do planner");
setSize(width, height);
setLocation(x, y);
JPanel mainPanel = new JPanel();
mainPanel.setBackground(Color.blue);
}
}
Connection.java
public class Connection {
public static Connection getConnection() throws SQLException {
Connection conn = null;
try
{
Class.forName("com.mysql.jdbc.Driver");
String url = "jdbc:mysql://h2318966.stratoserver.net/";
String user = "root";
String password = "";
conn = (Connection) DriverManager.getConnection(url, user, password);
System.out.println("Connection established");
}
catch(ClassNotFoundException e)
{
System.out.println(e.getMessage());
System.exit(0);
}
catch(SQLException e)
{
System.out.println(e.getMessage());
System.exit(0);
}
return conn;
}
}
我尝试在mysql.java中使用新的连接,但我可能是一个彻头彻尾的白痴。如果你们能帮助我那会很棒。
答案 0 :(得分:0)
您可以在url字符串中将以下代码与您自己的主机和数据库名称一起使用。我测试了它。
注意:在项目中包含mysql-connector.jar
Mysql.java
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Toolkit;
import java.sql.SQLException;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class Mysql {
public static void main(String[] args) {
Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
int w = screenSize.width;
JFrame frame = new MainFrame(w/5, 100, 2*w/5, 0);
frame.show();
try {
new Connection().getConnection();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
class MainFrame extends JFrame {
MainFrame(int width, int height, int x, int y) {
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setTitle("Todothelydoo - To do planner");
setSize(width, height);
setLocation(x, y);
JPanel mainPanel = new JPanel();
mainPanel.setBackground(Color.blue);
}
}
Connection.java
import java.sql.DriverManager;
import java.sql.SQLException;
public class Connection {
public static java.sql.Connection getConnection() throws SQLException {
java.sql.Connection conn = null;
try
{
Class.forName("com.mysql.jdbc.Driver");
String url = "jdbc:mysql://localhost/database_name";
String user = "root";
String password = "";
conn = DriverManager.getConnection(url, user, password);
System.out.println("Connection established");
}
catch(ClassNotFoundException e)
{
System.out.println(e.getMessage());
System.exit(0);
}
catch(SQLException e)
{
System.out.println(e.getMessage());
System.exit(0);
}
return conn;
}
}
答案 1 :(得分:0)
公共类Mysql扩展了Connectionn {
public static void main(String[] args) {
Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
int w = screenSize.width;
JFrame frame = new MainFrame(w/5, 100, 2*w/5, 0);
frame.show();
Connectionn con=new Connectionn();
try {
con.getConnection();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}