java - 无法解析连接变量

Question

public class GestorBase{

 public static void main(String[] args){
  try
  {
   Class.forName("org.sqlite.JDBC");
  }
  catch (ClassNotFoundException e) {
   System.out.println("Unable to load driver class");
   // TODO: handle exception
  }
  try {
   Connection con = DriverManager.getConnection("jdbc:sqlite:db/Freepark.sqlite");
  } catch (SQLException e) {
   // TODO Auto-generated catch block
   System.out.println("error al buscar la base de datos");
  }

  Statement sentencia = con.createStatement();


 }}

eclipse 说:

"con" variable cannot be resolved to a type.

为什么？

Answer 1

con 变量是 try block 的局部变量，

try {
   Connection con = DriverManager.getConnection("jdbc:sqlite:db/Freepark.sqlite");
  }   

您正在 try block 之外访问 con。

应该是

Connection con = null;
Statement sentencia = null;
try {
      con = DriverManager.getConnection("jdbc:sqlite:db/Freepark.sqlite");
      sentencia = con.createStatement();
 } catch (SQLException e) {
      // TODO Auto-generated catch block
      System.out.println("error al buscar la base de datos");
 } catch (Exception ex){

     //handle it
 }

• Have a look at variable scope and blocks