view layer: JSP and display data transmission:
Controller layer:
servlet: multiple requests to call a servlet:
@WebServlet(name ="CustomerServlet",urlPatterns ="*.do")
public class CustomerServletextends HttpServlet {
// protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// String method = request.getParameter("method");
// switch (method){
// case "add":add(request,response);break;
// case "query":query(request,response);break;
// case "delete":delete(request,response);break;
// }
// }
protected void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
// get 1 ServletPath: /edit.do or add.do
String servletPath = request.getServletPath();
// 2. removing / and .do, obtain such string edit and add similar
try {
String methodName = servletPath.substring(5);
methodName = methodName.substring(0,methodName.length()-3);
System.out.println(methodName);
Method // 3. MethodName acquired by reflection corresponding
Method method = getClass().getDeclaredMethod(methodName,HttpServletRequest.class,HttpServletResponse.class);
// 4. The method of using reflection to invoke the corresponding
method.invoke(this,request,response);
}
catch (Exception e) {
request.getRequestDispatcher("/WEB-INF/error.jsp").forward(request,response);
// e.printStackTrace ();
}
}
private void add(HttpServletRequest request,HttpServletResponse response)throws ServletException{
System.out.println("add");
}
private void query(HttpServletRequest request,HttpServletResponse response)throws ServletException{
System.out.println("query");
}
private void delete(HttpServletRequest request,HttpServletResponse response)throws ServletException{
System.out.println("delete");
}
protected void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
doPost(request,response);
}
}
Data layer:
JDBC tool uses DBUtils
Database connection pool: c3p0
By DAO design model, reflective, generic, universal configuration database background operation code:
Greatly increasing the reusability of code database back-end operations
