java - 如何在 java netbeans 类中存储 mysql 的数据库连接方法，并在 jFrame 中需要时调用它

Question

public void Helper(){
    try{Class.forName("com.mysql.jdbc.DRIVER"); 

    Connection con=DriverManager.getConnection("jdbc:mysql://localhost/kutbuddin","root","*****");

       Statement stmt=con.createStatement();
    }
    catch(Exception e){}

现在我想在为 jButton 编码时调用以下类，而不必一次又一次地编写连接语句

Answer 1

让我们看看您发布的代码。我假设您正在尝试获取数据库连接。如果这是真的，为什么不从该方法返回一个呢？

这是我的写法:

package database.util;

import org.mariadb.jdbc.MySQLDataSource;

import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.DatabaseMetaData;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

/**
 * Database utilities
 * Created by Michael
 * Creation date 5/3/2016.
 * @link https://stackoverflow.com/questions/36999860/mysql-driver-problems/37000276#comment61553720_37000276
 */
public class DatabaseUtils {

    public static final String DEFAULT_DRIVER = "org.mariadb.jdbc.Driver";
    public static final String DEFAULT_URL = "jdbc:mariadb://localhost:3306/contact";
    public static final String DEFAULT_USERNAME = "contact";
    public static final String DEFAULT_PASSWORD = "contact";
    public static final String DEFAULT_HOST = "localhost";
    public static final int DEFAULT_PORT = 3306;
    public static final String DEFAULT_DATABASE = "contact";

    public static void main(String[] args) {
        Connection connection = null;
        try {
            connection = createConnection(DEFAULT_DRIVER, DEFAULT_URL, DEFAULT_USERNAME, DEFAULT_PASSWORD);
            DatabaseMetaData meta = connection.getMetaData();
            System.out.println(String.format("Connected to %s version %s", meta.getDatabaseProductName(), meta.getDatabaseProductVersion()));
        } catch (ClassNotFoundException | SQLException e) {
            e.printStackTrace();
        } finally {
            close(connection);
        }
    }

    public static DataSource createDataSource(String host, int port, String database) throws ClassNotFoundException, SQLException {
        return new MySQLDataSource(host, port, database);
    }

    public static Connection createConnection(String driverClass, String url, String username, String password) throws ClassNotFoundException, SQLException {
        Class.forName(driverClass);
        return DriverManager.getConnection(url, username, password);
    }

    public static void close(Connection connection) {
        try {
            if (connection != null) {
                connection.close();
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    public static void close(Statement st) {
        try {
            if (st != null) {
                st.close();
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    public static void close(ResultSet rs) {
        try {
            if (rs != null) {
                rs.close();
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}