JSF教程 - JSF注入托管Bean示例

JSF教程 - JSF注入托管Bean示例


下面的代码显示了如何做bean注入。

我们首先定义一个消息bean，它有一个string属性存储信息。

@ManagedBean(name="message")
@SessionScoped
public class MessageBean implements Serializable {

  private static final long serialVersionUID = 1L;
  
  private String sayWelcome = "Welcome to JSF 2.0";

然后我们定义另一个托管bean并注入MessageBean @ManagedProperty 注释。

@ManagedBean
@SessionScoped
public class UserBean implements Serializable {

  private static final long serialVersionUID = 1L;
  
  @ManagedProperty(value="#{message}")
  private MessageBean messageBean;

  public void setMessageBean(MessageBean messageBean) {
    this.messageBean = messageBean;
  }


例子

下面的代码来自UserBean.java。

package cn.w3cschool.common;

import java.io.Serializable;

import javax.faces.bean.ManagedBean;
import javax.faces.bean.ManagedProperty;
import javax.faces.bean.SessionScoped;

@ManagedBean
@SessionScoped
public class UserBean implements Serializable {

  private static final long serialVersionUID = 1L;
  
  @ManagedProperty(value="#{message}")
  private MessageBean messageBean;

  public void setMessageBean(MessageBean messageBean) {
    this.messageBean = messageBean;
  }

  private String name;

  public String getName() {
    return name;
  }

  public void setName(String name) {
    this.name = name;
  }
  
  public String getSayWelcome(){
    //check if null?
    if("".equals(name) || name ==null){
      return "";
    }else{
      return messageBean.getSayWelcome() + name;
    }
  }
  
}

以下代码来自demo.xhtml。

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
      xmlns:f="http://java.sun.com/jsf/core"      
      xmlns:h="http://java.sun.com/jsf/html">
 
    <h:body>
 
      <h:form>
         <h:inputText id="name" value="#{userBean.name}"></h:inputText>
         <h:commandButton value="Welcome Me">
         <f:ajax execute="name" render="output" />
         </h:commandButton>
 
         <h2><h:outputText id="output" value="#{userBean.sayWelcome}" /></h2>  
      </h:form>
 
    </h:body>
</html>

下面的代码来自MessageBean.java。

package cn.w3cschool.common;
import java.io.Serializable;

import javax.faces.bean.ManagedBean;
import javax.faces.bean.SessionScoped;

@ManagedBean(name="message")
@SessionScoped
public class MessageBean implements Serializable {

  private static final long serialVersionUID = 1L;
  
  private String sayWelcome = "Welcome to JSF 2.0";

  public String getSayWelcome() {
    return sayWelcome;
  }

  public void setSayWelcome(String sayWelcome) {
    this.sayWelcome = sayWelcome;
  }

}

Download Inject-Managed-Beans.zip


跑步

将生成的WAR文件从目标文件夹复制到Tomcat部署文件夹并运行Tomcat-Install-folder / bin / startup.bat。

Tomcat完成启动后，在浏览器地址栏中键入以下URL。

http://localhost:8080/simple-webapp/demo.xhtml
juanshu.xyz
0.0579s