我正在制作一个程序，我将从 excel 文件中读取数据并将它们存储在表格中。每个表都有文件名和文件中的数据。在程序开始时，我想检查用户是否给出了正确的文件路径，然后检查表是否已经存在于数据库中。我会怎么做？我的意思是在读取用户的路径后，我只想使用我在代码中指定的文件名作为“tablename”来检查数据库中是否已经存在。
我的获取连接、给出路径和测试路径的程序如下。用户应该给出的正确路径如下：C:\Users\myuser\Docs\myfile.xls
Class.forName("com.mysql.jdbc.Driver");
Connection con = (Connection) DriverManager.getConnection(
"jdbc:mysql://localhost:3306/kainourgia", "root", "root");
DatabaseMetaData meta = (DatabaseMetaData) con.getMetaData();
ResultSet res = meta.getCatalogs();
System.out.println("List of the databases: ");
while (res.next()) {
System.out.println(" " + res.getString(1));
}
String strfullPath = "";
Scanner scanner = new Scanner(System.in);
while (true) {
System.out.println("Please enter the fullpath of the file:");
strfullPath = scanner.nextLine();
File f = new File(strfullPath);
if (f.canRead())
break;
System.out.println("Error:File does not exist");
}
String file = strfullPath.substring(strfullPath.lastIndexOf('/') + 1);
System.out.println(file.substring(0, file.indexOf('.')));
System.out.println("The path of the file is:");
String Path = strfullPath.substring(strfullPath.indexOf('\\') - 2,
(strfullPath.lastIndexOf('\\') - 2));
System.out.println(Path);
@SuppressWarnings("unused")
String filename = strfullPath
.substring(strfullPath.lastIndexOf('\\') + 1);
System.out.println("The filename is");
System.out.println(filename);
String[] parts = filename.split("\\.");
String tablename = parts[0];
DatabaseMetaData md2 = (DatabaseMetaData) con.getMetaData();
ResultSet rs = md2.getTables(null, null, "tablename", null);
System.out.println("The name of the table would be:");
System.out.println(tablename);