我想獲取主要方法會產生的值,並在getConnection方法中使用它們。但是,當我嘗試訪問getConnection方法時,返回空值。如何從getConnection方法訪問主方法的值?
我想使用ConnectionManager類連接到數據庫。
下面的代碼。
public class ConnectionManager {
public static String database;
public static String dbuser;
public static String dbpassword;
public static void main(String args[]) {
Properties prop = new Properties();
InputStream input = null;
try {
input = new FileInputStream("config.properties");
// load a properties file
prop.load(input);
database = prop.getProperty("database");
dbuser = prop.getProperty("dbuser");
dbpassword = prop.getProperty("dbpassword");
System.out.println(database);
} catch (IOException ex) {
ex.printStackTrace();
} finally {
if (input != null) {
try {
input.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
public static String url = "jdbc:mysql://localhost:3306/" + database;
private static String driverName = "com.mysql.jdbc.Driver";
private static String username = dbuser;
private static String password = dbpassword;
private static Connection con;
public static Connection getConnection() {
try {
Class.forName(driverName);
try {
con = DriverManager.getConnection(url, username, password);
} catch (SQLException ex) {
// log an exception. For example:
System.out.println("Failed to create the database connection.");
System.out.println(url + " " + username + " " + password);
}
} catch (ClassNotFoundException ex) {
System.out.println("Your driver has not been found.");
}
return con;
}
}
參數的值將來自公共靜態無效的主要(字符串參數[]) –
謝謝。它進行了一些修改。 –