未报告异常ClassNotFoundException的;必须捕获或抛出的Class.forName（在sun.jdbc.odbc.JdbcOdbcDriver）

Question

import java.sql.*; 
import java.awt.*; 
import java.awt.event.*; 
import javax.swing.*; 
class DeleteDemo extends Frame implements 
    ActionListener { 
         Label l1; 
         Button b1; 
         TextField t1; 
         DeleteDemo() 
         { 
         setVisible(true); 
         setSize(400,400); 
         l1=new Label("Enter Id"); 
         b1=new Button("Delete"); 
         t1=new TextField(20); 
         setLayout(new FlowLayout()); 
         add(l1);add(t1); 
         add(b1); 
         b1.addActionListener(this); 
         } 


     public void actionPerformed(ActionEvent e) 
     { 
          if(e.getSource()==b1) 
          {  
           try 
           {   
             System.out.println("Data try to delete"); 
             String id=t1.getText(); 
             l1.setText("hi"); 
             Class.forName("sun.jdbc.odbc.JdbcOdbcDriver"); 
         Connection con=DriverManager.getConnection("Jdbc:Odbc:xyz","",""); 
       Statement st=con.createStatement(); 
       st.executeUpdate("delete from tblEmp where id ='"+id+"' "); 
       System.out.println("Data has been deleted"); 
      }catch(SQLException eb){} 
     } 
    }  
     public static void main(String args[ ])  { 
      DeleteDemo dtl=new DeleteDemo();  } 
     } 

Answer 1

Class.forName(String)抛出一个ClassNotFoundException，如果它不能加载谁的名字传递给它（例如类，如果你在你的类路径中缺少一个jar）。这是一个检查的异常，并且必须被向上抛出（例如添加throws ClassNotFoundException到您的方法的声明），或抓住：

try { 
    System.out.println("Data try to delete"); 
    String id=t1.getText(); 
    l1.setText("hi"); 
    Class.forName("sun.jdbc.odbc.JdbcOdbcDriver"); 
    Connection con=DriverManager.getConnection("Jdbc:Odbc:xyz","",""); 
    Statement st=con.createStatement(); 
    st.executeUpdate("delete from tblEmp where id ='"+id+"' "); 
    System.out.println("Data has been deleted"); 
} catch(ClassNotFoundException cne) { 
    System.err.println("Could not load JDBC driver"); 
} catch(SQLException eb) { 
    System.err.println("Could not delete data"); 
}