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[英]How do I call data from a table in a database into a java class in netbeans?
[英]how do i store Database connectivity methods of mysql in a java netbeans class and call it whenever i need it in a jFrame
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){}
現在,當我為jButton編碼時,我想調用以下類,而不必一次又一次編寫連接性語句
讓我們看看您發布的代碼。 我假設您正在嘗試建立數據庫連接。 如果是這樣,為什么不從方法中返回一個呢?
這是我的寫法:
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();
}
}
}
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