java - 如何接收2个或更多不同的异常？

Question

我编写了一段代码将用户添加到数据库中。当我们收到重复的条目时，我需要重定向到 EmpInfo.jsp。我需要为此使用更多异常，而且我想知道如何重定向。

    response.setContentType("text/html");
    PrintWriter out = response.getWriter();
    Connection conn = null;
    String url = "jdbc:mysql://localhost:3306/";
    String dbName = "cervlet";
    String driver = "com.mysql.jdbc.Driver";
    String userName = "root"; 
String password = "1234";
int Empid =Integer.parseInt(request.getParameter("Empid").toString()); 
String Name = request.getParameter("Name").toString();
int Age =Integer.parseInt(request.getParameter("Age").toString()); 
int Salary =Integer.parseInt(request.getParameter("Salary").toString());
PreparedStatement stmt;
try {
 Class.forName(driver).newInstance();
 conn = DriverManager.getConnection(url+dbName,userName,password);
 System.out.println("Connected to the database");
 //ArrayList al=null;
 //ArrayList userList =new ArrayList();
 String query = "insert into employee set Empid='"+Empid+"',name='"+Name+"',Age='"+Age+"',Salary='"+Salary+"'";
stmt = (PreparedStatement) conn.prepareStatement(query);
  int i = 0;
try {
   i = stmt.executeUpdate(query);
    }
  catch (SQLException e) {
    String nextj = "/AddUser.jsp";
    RequestDispatcher rd = getServletContext().getRequestDispatcher(nextj);
   rd.forward(request, response);
    }
   System.out.println("i="+i);
System.out.println("query: " + query);
//if(i==0)
 //{
  //String nextj = "/EmpInfo.jsp";
    //RequestDispatcher cd = getServletContext().getRequestDispatcher(nextj);
    //cd.forward(request, response);
 //response.sendRedirect("servletRecord");
//}
 response.sendRedirect("/EmpInfo.jsp");
 conn.close();
 System.out.println("Disconnected from database");

} catch (Exception e) {
e.printStackTrace();

更新

当它添加新条目时，我需要重定向到EmpInfo.jsp。执行方法 executeUpadte() 后，我使用了它的返回值值重定向到另一个名为 EmpInfo.jsp 的页面。但它没有重定向。我正在使用 eclipse 。告诉我.jsp页面多重重定向的常用方法。

Answer 1

好吧，如果您问如何捕获不同的异常，则可以使用以下代码:

try {
    ...
    // Code that may throw a few types of exceptions
    ...
} catch(FileNotFoundException fnfe) {
    // handle very specific exceptions
} catch (IOException ioe) {
    // handle less specific exceptions
} catch (Exception e) {
    // handle the most generic exception case
} 

这将允许您在一个代码块中处理多种异常类型。