6.3.2 登录流程的代码
/*--------------------------------------------------------------------------------------*/
//1、用户登录界面 - login.jsp
＜!- 部分HTML代码此处省略 -- ＞
＜form name="teaForm" method="post" action="＜%=contextPath%＞/login.do"＞
＜table border="0" cellspacing="0" cellpadding="0"＞
＜tr＞
＜td width="60"＞＜font size="2"＞用户类型＜/font＞＜/td＞
＜td＞
＜input type="radio" value="0" name="actortype" checked＞＜font size="2"＞系统管理员 ＜/font＞
＜input type="radio" value="1" name="actortype"＞＜font size="2"＞学生 ＜/font＞
＜input type="radio" value="2" name="actortype"＞＜font size="2"＞老师 ＜/font＞
＜/td＞
＜/tr＞
＜tr＞
＜td width="60"＞＜font size="2"＞用户名＜/font＞＜/td＞
＜td＞＜input name="username" value="" size="12"＞ *＜/td＞
＜/tr＞
＜tr＞
＜td width="60"＞＜font size="2"＞口令＜/font＞＜/td＞
＜td＞＜input type="password" name="password" value="" size="8" maxlength="8"＞ *＜/td＞
＜/tr＞
＜/table＞
＜br＞
＜table border="0" cellspacing="0" cellpadding="0"＞
＜tr＞
＜td width="50"＞ ＜/td＞
＜td＞＜input type="submit" value="登 录"＞＜/td＞
＜/tr＞
＜/table＞
＜/form＞ |
/*--------------------------------------------------------------------------------------*/
//2、Struts程序
//2.1 LoginForm.java（存储用户在页面上提交的用户名、口令和用户类型）
package com.chenxc.coursesonline.struts;
/**
* Title: LoginForm
* Description: 存储登录信息
* Time: 2004-3-20
* Company:
* Author: chenxc
* version 1.0
*/
import java.util.*;
public class LoginForm extends org.apache.struts.action.ActionForm{
private String username; //用户名
private String password; //口令
private int actortype; //用户类型
//用户名
public void setUsername(String username) {
this.username = username;
}
public String getUsername() {
return username;
}
//口令
public void setPassword(String password) {
this.password = password;
}
public String getPassword() {
return password;
}
//用户类型
public void setActortype(int actortype)
{
this.actortype = actortype;
}
public int getActortype()
{
return actortype;
}
} |
//2.2 LoginAction.java（控制登录流程的走向）
package com.chenxc.coursesonline.struts;
/**
* Title: LoginAction
* Description: 登录验证
* Time: 2004-3-20
* Company:
* Author: chenxc
* version 1.0
*/
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.util.*;
import org.apache.struts.action.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.ServletException;
import com.chenxc.coursesonline.struts.*;
public class LoginAction extends org.apache.struts.action.Action{
public ActionForward execute(ActionMapping mapping,ActionForm actionForm,HttpServletRequest request,HttpServletResponse response) throws Exception
{
ActionErrors errors = new ActionErrors();
HttpSession session = request.getSession();
ActionForward forward = null;
LoginForm loginForm = (LoginForm)actionForm;
FacadeBean facadeBean = new FacadeBean();
if(facadeBean.actorlogin(loginForm.getUsername(),loginForm.getPassword(),loginForm.getActortype()))
{
forward = mapping.findForward("success");
return forward;
}
return (new ActionForward(mapping.getInput()));
}
} |
//2.3 FacadeBean.java（实现登录验证）
package com.chenxc.coursesonline.struts;
/**
* Title: FacadeBean
* Description: 负责与Session Bean沟通
* Time: 2004-3-20
* Company:
* Author: chenxc
* version 1.0
*/
import com.chenxc.coursesonline.ejb20.*;
import javax.naming.*;
import java.util.Properties;
import javax.rmi.PortableRemoteObject;
import javax.ejb.CreateException;
import java.rmi.RemoteException;
public class FacadeBean
extends Object {
private static final String ERROR_NULL_REMOTE = "Remote interface reference is null. It must be created by calling one of the Home interface methods first.";
private static final int MAX_OUTPUT_LINE_LENGTH = 100;
private CoursesFacadeHome coursesFacadeHome = null;
private CoursesFacade coursesFacade = null;
//Construct the FacadeBean
public FacadeBean() {
initialize();
}
public void initialize() {
try {
//get naming context
Context context = getInitialContext();
//look up jndi name
Object ref = context.lookup("CoursesFacade");
//look up jndi name and cast to Home interface
coursesFacadeHome = (CoursesFacadeHome) PortableRemoteObject.narrow(ref,CoursesFacadeHome.class);
}
catch (Exception e) {
e.printStackTrace();
}
}
private Context getInitialContext() throws Exception {
String url = "t3://192.168.100.134:7001";
String user = null;
String password = null;
Properties properties = null;
try {
properties = new Properties();
properties.put(Context.INITIAL_CONTEXT_FACTORY， "weblogic.jndi.WLInitialContextFactory");
properties.put(Context.PROVIDER_URL, url);
if (user != null) {
properties.put(Context.SECURITY_PRINCIPAL, user);
properties.put(Context.SECURITY_CREDENTIALS,
password == null ? "" : password);
}
return new InitialContext(properties);
}
catch (Exception e) {
throw e;
}
}
//actorlogin
public boolean actorlogin(String username, String password, int actortype) {
try {
coursesFacade = coursesFacadeHome.create();
if (coursesFacade.actorLogin(username, password, actortype)) {
return true;
}
else
{
return false;
}
}
catch (CreateException ex) {
ex.printStackTrace();
}
catch (RemoteException ex) {
ex.printStackTrace();
}
return false;
}
} |
/*--------------------------------------------------------------------------------------*/
//3、Session Bean程序
//3.1 SessionFacadeHome.java
package com.chenxc.coursesonline.ejb20;
import javax.ejb.*;
import java.util.*;
import java.rmi.*;
public interface SessionFacadeHome extends javax.ejb.EJBHome {
public SessionFacade create() throws CreateException, RemoteException;
} |
//3.2 SessionFacade.java
package com.chenxc.coursesonline.ejb20;
import javax.ejb.*;
import java.util.*;
import java.rmi.*;
public interface SessionFacade extends javax.ejb.EJBObject {
public boolean actorLogin(String actor, String password, int actortype) throws RemoteException;
} |
//3.2 SessionFacadeBean.java
package com.chenxc.coursesonline.ejb20;
import javax.ejb.*;
import javax.naming.*;
import java.rmi.RemoteException;
public class SessionFacadeBean implements SessionBean {
SessionContext sessionContext;
ActorHome actorHome;
Actor actor;
public void ejbCreate() throws CreateException {
try
{
Context ctx = new InitialContext();
actorHome = (ActorHome)ctx.lookup("Actor");
}
catch (Exception ex) {
throw new EJBException(ex);
}
}
public void ejbRemove() {
/**@todo Complete this method*/
}
public void ejbActivate() {
/**@todo Complete this method*/
}
public void ejbPassivate() {
/**@todo Complete this method*/
}
public void setSessionContext(SessionContext sessionContext) {
this.sessionContext = sessionContext;
}
public boolean actorLogin(String username, String password, int actortype) {
try
{
actor = actorHome.findByName(username,actortype);
if(actor.getPassword().equals(password))
{
System.out.println(username + " 登录成功！");
return true;
}
}catch(ObjectNotFoundException ex) {
}
catch(Exception ex) {
ex.printStackTrace();
}
return false;
}
} |
/*--------------------------------------------------------------------------------------*/
//4、为Entity Bean(Actor)新增一个findByName的Finder，如下图
Finder名findByName，返回值Actor，输入参数用户名，用户类型，接口local home，EJB-QL: SELECT OBJECT(a) FROM Actor AS a WHERE a.username = ?1 AND a.actortype = ?2
6.3.3 阶段总结
Client -＞ Struts -＞ Session Bean -＞ Entity Bean，实现一个登录流程用了十几个java程序，真是累人的说。一个JSP程序就可以实现的功能却要大阵战对待，杀鸡用牛刀乎？
答案是否定的，因为EJB存在的意义在于分布式计算和分层的思想。
6.4未完成的
写到这里，CoursesOnline系统只实现了系统登录验证的功能，主要的业务逻辑基本上没实现，但MVC框架，Facade Design Pattern都或多或少有所描述，继续完成CoursesOnline系统应该不会太困难。
另外由于使用CMP查询记录集时处理起来比较麻烦，所以在浏览课程或浏览学生等记录集查询时可以考虑用BMP来实现，或者干脆在Session Bean实现。
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