用JSF实现依赖注入

无意中看到JSF中的Managed Properties，不禁突发奇想: 用JSF能实现依赖注入吗?理论上是可以通的,于是开始了自己的尝试,只是写一个简单的Login页面.

首先,写一个IUserService的接口,接口中只有属性方法: getUsername,getPassword,setUsername,setPassword四个方法.代码如下:

package net.moon.service;

public interface IUserService {
StringgetUsername();
StringgetPassword();
voidsetUsername(Stringusername);
voidsetPassword(Stringpassword);
}

用一个类实现该接口,代码如下:

package net.moon.model;

import net.moon.service.IUserService;

public class UserInfo implements IUserService {
privateStringusername;
privateStringpassword;
/**
*@returntheusernmae
*/
publicStringgetUsername(){
returnusername;
}
/**
*@paramusernmaetheusernmaetoset
*/
publicvoidsetUsername(Stringusernmae){
this.username=usernmae;
}
/**
*@returnthepassword
*/
publicStringgetPassword(){
returnpassword;
}
/**
*@parampasswordthepasswordtoset
*/
publicvoidsetPassword(Stringpassword){
this.password=password;
}
}

写一个事务类,实现login功能,其中有一个类型为IUserService的域,代码如下:

package net.moon.business;

import net.moon.service.IUserService;

public class UserBO {

IUserServiceuser;

publicStringlogin(){
Stringresult="FAILED";
//System.out.println(result);
if(user.getUsername().equalsIgnoreCase("admin")
&&user.getPassword().equals("password")){
result="PASS";
}
returnresult;
}

/**
*@returntheuser
*/
publicIUserServicegetUser(){
returnuser;
}

/**
*@paramusertheusertoset
*/
publicvoidsetUser(IUserServiceuser){
this.user=user;
}
}

注意该类中的属性方法setUser,其中的参数user作为IUserService的接口类型.然后就是用什么方法对user进行注入,这时候就要想到JSF中的Managed Properties.

首先在,faces-config中配置UserInfo类为MBean,代码如下:

< managed-bean >
< managed-bean-name > userInfo </ managed-bean-name >
< managed-bean-class > net.moon.model.UserInfo </ managed-bean-class >
< managed-bean-scope > session </ managed-bean-scope >
</ managed-bean >

然后将事务类UserBO也配置为MBean,代码如下:

< managed-bean >
< managed-bean-name > userBO </ managed-bean-name >
< managed-bean-class >
net.moon.business.UserBO
</ managed-bean-class >
< managed-bean-scope > request </ managed-bean-scope >
< managed-property >
< property-name > user </ property-name >
< property-class >
net.moon.service.IUserService
</ property-class >
< value > #{userInfo} </ value >
</ managed-property >
</ managed-bean >

注意蓝色显示部分,为userBO这个MBean配置了一个Managed Property,也就是要求JSF在实现userBO时,用userInfo这个MBean为其user这个域赋值,从而实现注入.

接下来就是页面的实现了,首先是login页面,代码如下:

<% @pagecontentType="text/html;charset=UTF-8" %>
<% @tagliburi="http://java.sun.com/jsf/html"prefix="h" %>
<% @tagliburi="http://java.sun.com/jsf/core"prefix="f" %>

< html >
< head >
< meta http-equiv ="Content-Type" content ="text/html;charset=UTF-8" />
< title ></ title >
</ head >
< body >
< f:view >
< h:form >
< h:panelGrid border ="1" columns ="2" >
< h:outputText value ="UserName:" ></ h:outputText >
< h:inputText value ="#{userInfo.username}" ></ h:inputText >
< h:outputText value ="Password:" ></ h:outputText >
< h:inputText value ="#{userInfo.password}" ></ h:inputText >
</ h:panelGrid >
< h:commandButton value ="Login" action ="#{userBO.login}" ></ h:commandButton >
</ h:form >
</ f:view >
</ body >
</ html >

表示登录成功的页面welcome.jsp,代码如下:

配置导航如下:

< navigation-rule >
< display-name > login </ display-name >
< from-view-id > /login.jsp </ from-view-id >
< navigation-case >
< from-action > #{userBO.login} </ from-action >
< from-outcome > PASS </ from-outcome >
< to-view-id > /welcome.jsp </ to-view-id >
</ navigation-case >
< navigation-case >
< from-action > #{userBO.login} </ from-action >
< from-outcome > FAILED </ from-outcome >
< to-view-id > /login.jsp </ to-view-id >
</ navigation-case >
</ navigation-rule >

以上代码在JDK 1.6,JSF 1.2,Tomcat 6.0下测试通过.

用JSF实现依赖注入

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