Struts 2 automatically receives parameters by action

There are three main methods of action receiving parameters in Struts2:

1. Receive parameters using the properties of the action: (via Property-driven)

A. Definition: Define attributes in the action class, create get and set methods;

B. Receive: Receive parameters through attributes, such as: UserName;

C. Send: Use property name to pass parameters, such as: USER1!ADD?USERNAME=MAGCI;

Jsp:

<form action= "Sys/login.action" method= "POST" >  
 <input type= "text" name= "username" >  
 <input Type= "Submit" value= "Submit" >  
</form>

Action: Gets directly through the get, set method.

public class Sysaction extends actionsupport{  
 private String username;  
        
 Public String Login () throws Exception {  
  System.out.println (username);  
  return SUCCESS;  
 }  
        
 Public String GetUserName () {return  
  username;  
 }  
 public void Setusername (String username) {  
  this.username= username;  
 }  
}

2. Use Modeldriven to receive parameters: (model-driven, the Modeldriven<t> interface must be implemented.) Inconvenient for the second way to pass in multiple model

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A. Definition: The action implements the Modeldriven generic interface, defines the object of the model class (must be New), and returns the object through the Getmodel method;

B. Receive: Parameters are received through the properties of the object, such as: User.getusername ();

C. Send: Pass parameters directly using attribute names, such as: USER2!ADD?USERNAME=MGC

Jsp:

<form action= "Sys/login.action" method= "POST" >  
 <input type= "text" name= "username" >  
 <input Type= "Submit" value= "Submit" >  
</form>

Action: The Getmodel () method must be implemented

public class Sysaction extends Actionsupport implements modeldriven<user>{  
 Private user user;  
       
 Public String Login () throws Exception {  
  System.out.println (Getmodel (). GetUserName ());  
  return SUCCESS;  
 }  
       
 Public User Getmodel () {  
  if (null = = user) {return  
   user = new User ();  
  }  
  return user;  
 }  

3. Use Domainmodel to receive parameters: (the third domain model method can not implement MODELDRIVEN<T> at all, or you can use the properties of multiple model objects. )

A. Definition: Define the Model class, define the object of the model class (without new) in the action, and create the Get and set methods of the object;

B. Receive: Parameters are received through the properties of the object, such as: User.getusername ();

C. Send: Use the properties of the object to pass parameters, such as: USER2!ADD?USER.USERNAME=MGC;

Jsp:

<form action= "Sys/login.action" method= "POST" >  
 <input type= "text" name= "User.username" >  
 < Input type= "text" name= "Teacher.level" >  
 <input type= "Submit" value= "Submit" >  
</form>

Action: The set method must be supplied

public class Sysaction extends actionsupport{  
 Private user user;  
 Private Teacher Teacher;  
       
 Public String Login () throws Exception {  
  System.out.println (User.getusername ());  
  System.out.println (Teacher.getlevel ());  
  return SUCCESS;  
 }  
       
 public void SetUser (user user) {  
  this.user = user  
 }  
 public void Setteacher (Teacher Teacher) {  
  this.teacher = Teacher;  
 }  
}