Implement crud in struts2

Crud is the abbreviation of create, read, update, and delete. It is a microcosm of common applications.

View instances:

Employee. Java class:

Package com. LLP. Crud;

Public class employee {
Private string employeeid;
Private string firstname;
Private string lastname;
Public String getemployeeid (){
Return employeeid;
}
Public void setemployeeid (string employeeid ){
This. employeeid = employeeid;
}
Public String getfirstname (){
Return firstname;
}
Public void setfirstname (string firstname ){
This. firstname = firstname;
}
Public String getlastname (){
Return lastname;
}
Public void setlastname (string lastname ){
This. lastname = lastname;
}
@ Override
Public String tostring (){
Return "Employee [employeeid =" + employeeid + ", firstname ="
+ Firstname + ", lastname =" + lastname + "]";
}
 
}

 

Operation class: Dao. Java, the operation set for data in this class: This class does not implement database connection operations, but only uses the set to simulate;

Package com. LLP. Crud;
Import java. util .*;
Public class Dao {
Private Static Map <string, employee> EMPs = new hashmap <string, employee> ();
 
/* The static initiator initializes the class, that is, the member variables that belong to the class,
* Automatically implemented by the system when the class is loaded such as memory
*
**/
Static {
Long id = system. currenttimemillis ();

Employee EMP = new employee ();
EMP. setemployeeid (ID + "");
EMP. setfirstname ("AA ");
EMP. setlastname ("AA ");

EMPs. Put (EMP. getemployeeid (), EMP );

EMP = new employee ();
EMP. setemployeeid (ID + 1 + "");
EMP. setfirstname ("BB ");
EMP. setlastname ("BB ");

EMPs. Put (EMP. getemployeeid (), EMP );

EMP = new employee ();
EMP. setemployeeid (ID + 2 + "");
EMP. setfirstname ("cc ");
EMP. setlastname ("cc ");

EMPs. Put (EMP. getemployeeid (), EMP );


}
 
/* Return an existing set */
Public list <employee> findall (){

Return new arraylist <employee> (EMPs. Values ());
}
 
/* Save */
Public void save (employee EMP ){
String id = system. currenttimemillis () + "";
EMP. setemployeeid (ID );
EMPs. Put (ID, EMP );
}
 
/* Update */
Public void Update (employee EMP ){
EMPs. Put (EMP. getemployeeid (), EMP );
}
 
/* Get */
Public Employee get (string employeeid ){
Employee EMP = NULL;
EMP = EMPs. Get (employeeid );
Return EMP;
}
 
/* Delete */
Public void Delete (string employeeid ){
EMPs. Remove (employeeid );
}
}

1. Do not use the modeldriven_preparable interceptor crud
Action class, employeeaction. Java:

Package com. LLP. Crud;

Import com. opensymphony. xwork2.actionsupport;
Import java. util .*;
Import org. Apache. struts2.interceptor. requestaware;

Public class employeeaction extends actionsupport implements requestaware {
 
Private Dao = New Dao ();
 
Private string employeeid;
 
Private string firstname;
 
Private string lastname;
 
Public void setemployeeid (string employeeid) {// to obtain the Relative ID value passed from the page
This. employeeid = employeeid;
}
 
 
Public String getemployeeid (){
Return employeeid;
}

Public String getfirstname (){
Return firstname;
}

Public void setfirstname (string firstname ){
This. firstname = firstname;
}

Public String getlastname (){
Return lastname;
}

Public void setlastname (string lastname ){
This. lastname = lastname;
}
 
Public String Update (){
// 1. Obtain the form information
// 2. encapsulate form information as an employee object
Employee EMP = Dao. Get (employeeid );
EMP. setemployeeid (employeeid );
EMP. setfirstname (firstname );
EMP. setlastname (lastname );

// 3. Call the update method of Dao
Dao. Update (EMP );
Return success;
}
Public string edit (){
// 1. Get the object corresponding to the employee ID from the database
Employee EMP = Dao. Get (employeeid );
// 2. Assign the attribute of the object obtained in 1 to the corresponding attribute of the current action.
Firstname = EMP. getfirstname ();
Lastname = EMP. getlastname ();

Return "edit-sucess ";
}
Public String add (){
// 1. Obtain the value of the firstname and lastname Request Parameters
// 2. encapsulate firstname and lastname as an employee object
Employee EMP = new employee ();
EMP. setfirstname (firstname );
EMP. setlastname (lastname );
// 3. Call the Save method of DAO to perform the save operation.
Dao. Save (EMP );

Return success;
}
Public String Delete (){
// 1. Get the employee ID
// 2. Call the delete method of Dao
Dao. Delete (employeeid );
Return success;
}
 
Public String list (){
// Obtain information about all the employees
// Put the employee information in the request
Requestmap. Put ("emplist", Dao. findall ());
Return "list-sucess ";
}
 
Private Map <string, Object> requestmap = NULL;
 
Public void setrequest (Map <string, Object> arg0 ){
Requestmap = arg0;
}
}

 

2. modeldriven interceptor

Package com. LLP. Crud;

Import com. opensymphony. xwork2.actionsupport;
Import com. opensymphony. xwork2.modeldriven;

Import java. util .*;
Import org. Apache. struts2.interceptor. requestaware;

Public class employeeaction extends actionsupport
Implements requestaware, modeldriven <employee> {
 
Private Dao = New Dao ();
 
Public Employee GetModel (){
EMP = new employee ();
Return EMP;
}

Public String Update (){
// 1. Obtain the form information
// 2. encapsulate form information as an employee object
// Employee EMP = Dao. Get (employeeid );
// EMP. setemployeeid (employeeid );
// EMP. setfirstname (firstname );
// EMP. setlastname (lastname );

// 3. Call the update method of Dao
Dao. Update (EMP );
Return success;
}
Public string edit (){
/// 1. Obtain the object corresponding to the employee ID from the database
// Employee EMP = Dao. Get (employeeid );
/// 2. Assign the attribute of the object obtained in 1 to the corresponding attribute of the current action.
// Firstname = EMP. getfirstname ();
// Lastname = EMP. getlastname ();
Employee emp2 = Dao. Get (EMP. getemployeeid ());
EMP. setfirstname (emp2.getfirstname ());
EMP. setlastname (emp2.getlastname ());

Return "edit-sucess ";
}

Private employee EMP = NULL;
 
Public String add (){
/// 1. Obtain the value of the firstname and lastname Request Parameters
/// 2. encapsulate firstname and lastname as an employee object
//
// EMP. setfirstname (firstname );
// EMP. setlastname (lastname );
/// 3. Call the Save method of DAO to perform the save operation.
Dao. Save (EMP );

Return success;
}
Public String Delete (){
// 1. Get the employee ID
// 2. Call the delete method of Dao
// Dao. Delete (employeeid );
Dao. Delete (EMP. getemployeeid ());
Return success;
}
 
Public String list (){
// Obtain information about all the employees
// Put the employee information in the request
Requestmap. Put ("emplist", Dao. findall ());
Return "list-sucess ";
}
 
Private Map <string, Object> requestmap = NULL;
 
Public void setrequest (Map <string, Object> arg0 ){
Requestmap = arg0;
}

}

 

3. preparable interceptor and paramsprepareparamsstack interceptor Stack

Package com. LLP. Crud;

Import com. opensymphony. xwork2.actionsupport;
Import com. opensymphony. xwork2.modeldriven;
Import com. opensymphony. xwork2.preparable;

Import java. util .*;
Import org. Apache. struts2.interceptor. requestaware;

Public class employeeaction extends actionsupport
Implements requestaware, modeldriven <employee>, preparable {
 
Private Dao = New Dao ();
 
Public void prepare () throws exception {
// Add a new employee or modify an employee
// EMP = new employee ();
// When querying an object from a database for displaying a form
// EMP = Dao. Get (EMP. getemployeeid ());
System. Out. println ("prepare ");

}
Public Employee GetModel (){
Return EMP;
}
 
Public void prepareupdate (){
EMP = new employee ();
}
Public String Update (){
// 1. Obtain the form information
// 2. encapsulate form information as an employee object
// Employee EMP = Dao. Get (employeeid );
// EMP. setemployeeid (employeeid );
// EMP. setfirstname (firstname );
// EMP. setlastname (lastname );

// 3. Call the update method of Dao
Dao. Update (EMP );
Return success;
}
 
Public void prepareedit (){
EMP = Dao. Get (employeeid );
}
Public string edit (){
/// 1. Obtain the object corresponding to the employee ID from the database
// Employee EMP = Dao. Get (employeeid );
/// 2. Assign the attribute of the object obtained in 1 to the corresponding attribute of the current action.
// Firstname = EMP. getfirstname ();
// Lastname = EMP. getlastname ();
Employee emp2 = Dao. Get (EMP. getemployeeid ());
EMP. setfirstname (emp2.getfirstname ());
EMP. setlastname (emp2.getlastname ());

Return "edit-sucess ";
}

Private employee EMP = NULL;
 
Public void prepareadd (){
EMP = new employee ();
}
Public String add (){
/// 1. Obtain the value of the firstname and lastname Request Parameters
/// 2. encapsulate firstname and lastname as an employee object
//
// EMP. setfirstname (firstname );
// EMP. setlastname (lastname );
/// 3. Call the Save method of DAO to perform the save operation.
Dao. Save (EMP );

Return success;
}
 
Private string employeeid;
 
Public void setemployeeid (string employeeid ){
This. employeeid = employeeid;
}
 
Public String Delete (){
// 1. Get the employee ID
// 2. Call the delete method of Dao
// Dao. Delete (employeeid );
Dao. Delete (employeeid );
Return success;
}
 
Public String list (){
// Obtain information about all the employees
// Put the employee information in the request
Requestmap. Put ("emplist", Dao. findall ());
Return "list-sucess ";
}
 
Private Map <string, Object> requestmap = NULL;
 
Public void setrequest (Map <string, Object> arg0 ){
Requestmap = arg0;
}
}

 

 

 

Struts. xml configuration:

<? XML version = "1.0" encoding = "UTF-8"?>
<! Doctype struts public
"-// Apache Software Foundation // DTD struts configuration 2.3 // en"
Http://struts.apache.org/dtds/struts-2.3.dtd>
<Struts>
<Constant name = "struts. UI. Theme" value = "simple"> </constant>
<Package name = "test_result" extends = "struts-Default">

<! -- Configure paramsprepareparamsstack as the default interceptor -->
<Default-interceptor-ref name = "paramsprepareparamsstack"> </default-interceptor-ref>

<Action name = "Employee _ *" class = "com. LLP. Crud. employeeaction" method = "{1}">
<! -- The value of the alwaysinvokeprepare parameter that overwrites the prepare interceptor is false -->
<Interceptor-ref name = "paramsprepareparamsstack">
<Param name = "prepare. alwaysinvokeprepare"> false </param>
</Interceptor-ref>

<Result name = "list-sucess">/WEB-INF/JSP/list. jsp </result>
<Result name = "edit-sucess">/WEB-INF/JSP/edit. jsp </result>
<! -- <Result name = "Update-success">/WEB-INF/JSP/list. jsp </result> -->
<Result name = "success" type = "redirectaction">
<Param name = "actionname"> employee_list </param>
</Result>
</Action>
</Package>
</Struts>

 

 

JSP page:

Index. jsp:

<% @ Page Language = "Java" Import = "Java. util. *" pageencoding = "UTF-8" %>

<! Doctype HTML public "-// W3C // dtd html 4.01 transitional // en">
<HTML>
<Head>
<Title> my JSP 'index. jsp 'starting page </title>
</Head>
<Body>
<A href = "employee_list"> employee list </a>
</Body>
</Html>

 

Display list. jsp:

<% @ Page Language = "Java" Import = "Java. util. *" pageencoding = "UTF-8" %>

<! Doctype HTML public "-// W3C // dtd html 4.01 transitional // en">
<HTML>
<Head>
<Title> my JSP 'list. jsp 'starting page </title>
</Head>
<Body>
<H4> Add new employee </H4>
<S: Form Action = "employee_add">
<S: textfield name = "firstname" label = "firstname"> </S: textfield>
<S: textfield name = "lastname" label = "lastname"> </S: textfield>
<S: Submit> </S: Submit>
</S: Form>
<S: If test = "# request. Employees! = NULL ">
<Br/>
<HR/>
<Br/>
<S: If test = "# request. Employees. size! = 0 ">
Display Information
<Table>
<Tr>
<TH> employeeid </Th>
<TH> firstname </Th>
<TH> lastname </Th>
<TH> edit </Th>
<TH> Delete </Th>
</Tr>
<S: iterator value = "# request. Employees">
<Tr>
<TD >$ {employeeid} </TD>
<TD >$ {firstname} </TD>
<TD >$ {lastname} </TD>
<TD> <a href = "employee_edit? Employeeid =$ {employeeid} "> edit </a> </TD>
<TD> <a href = "employee_delete? Employeeid =$ {employeeid} "> Delete </TD>
</Tr>
</S: iterator>
</Table>
</S: If>
<S: else>
No employee information
</S: else>
</S: If>
</Body>
</Html>

 

Edit. jsp:

<% @ Page Language = "Java" Import = "Java. util. *" pageencoding = "ISO-8859-1" %>
<% @ Taglib prefix = "S" uri = "/Struts-tags" %>
<! Doctype HTML public "-// W3C // dtd html 4.01 transitional // en">
<HTML>
<Head>
<Title> my JSP 'edit. jsp 'starting page </title>
</Head>
<Body>
<H4> edit employee </H4>
<S: Form Action = "employee_update">
<S: hidden name = "employeeid"> </S: hidden>
<S: textfield name = "firstname" label = "firstname"> </S: textfield>
<S: textfield name = "lastname" label = "lastname"> </S: textfield>
<S: Submit> </S: Submit>
</S: Form>
</Body>
</Html>