Layers of progressive Struts1 (i) introduced to struts by the servlet

Before we say Struts1, we're going to use the servlet to write a program to understand the cause and purpose of struts: a simple additions and deletions, we look at how the use of the servlet implementation, in order to figure out, we start from the most basic to write, and gradually progressive.

First edition

In this version we use the most conventional approach, delete and check each feature to use their own servlet, the content is as follows:

File tree

index.jsp

<form 

action= "Servlet/adduserservlet" method= "POST" >  
    name: <input type= "text" name= "username"/> <br/>  
    <input type= "Submit" value= "Submit"/>   
</form>

Servlet

For the convenience of stating that the four servlet content is basically the same here, take Adduserservlet and Delservlet for example:

Adduserservlet

Package com.tgb.struts1.servlet;  
      
Import java.io.IOException;  
      
Import javax.servlet.ServletException;  
Import Javax.servlet.http.HttpServlet;  
Import Javax.servlet.http.HttpServletRequest;  
Import Javax.servlet.http.HttpServletResponse;  
      
public class Adduserservlet extends HttpServlet {  
      
    @Override
    protected void doget (HttpServletRequest request, HttpServletResponse response)  
            throws Servletexception, IOException {  
            String username=request.getparameter ( "username");  
            Usermanager usermanager=new Usermanager ();  
            Usermanager.add (username);  
            Request.getrequestdispatcher ("/add_success.jsp"). Forward (request, response);  
      
    @Override
    protected void DoPost (HttpServletRequest request, httpservletresponse response)  
            throws Servletexception, IOException {  
            doget (request, response);  
    }  

Deluserservlet

Package com.tgb.struts1.servlet;  
Import java.io.IOException;  
Import javax.servlet.ServletException;  
Import Javax.servlet.http.HttpServlet;  
Import Javax.servlet.http.HttpServletRequest;  
Import Javax.servlet.http.HttpServletResponse;  
      
public class Deluserservlet extends HttpServlet {  
    @Override
    protected void doget (HttpServletRequest request, HttpServletResponse response)  
            throws Servletexception, IOException {  
            String username=request.getparameter ( "username");  
            Usermanager usermanager=new Usermanager ();  
            Usermanager.del (username);  
            Request.getrequestdispatcher ("/del_success.jsp"). Forward (request, response);  
    @Override
    protected void DoPost (HttpServletRequest request, httpservletresponse response)  
            throws Servletexception, IOException {  
            doget (request, response);  
    }  

Usermanager

Imitate logical processing layer and data processing layer

Package com.tgb.struts1.servlet;  
      
Import java.util.ArrayList;  
Import java.util.List;  
      
public class Usermanager {public  
    void Add (String username) {  
        System.out.println ("Usermanager------->add, Username= "+username);  
    }  
    public void del (String username) {  
        System.out.println ("Usermanager------->del,username=" +username);  
    }  
    public void Modify (String username) {  
        System.out.println ("Usermanager------->modify,username=" +username);  
    Public  
    List Query (String username) {  
        System.out.println ("Usermanager------->query,username=" + username);  
        List userlist=new ArrayList ();  
        UserList. Add ("a");  
        Userlist.add ("B");  
        Return userlist  
    }  
}