Question

我有一个简单的JSF项目，我使用<f:viewaction action="#{backingBean.init}"/>并且正在构建两次辅助bean。我找出了会话ID，每次调用都得到不同的会话ID。

的index.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:h="http://xmlns.jcp.org/jsf/html"
      xmlns:ui="http://xmlns.jcp.org/jsf/facelets"
      xmlns:f="http://xmlns.jcp.org/jsf/core">
<f:metadata>
    <f:viewAction action="#{backingBean.init}"/>
</f:metadata>
<h:body>
<h:outputLabel value="#{backingBean.text}"/>
</h:body>
</html>

BackingBean.java

package com.test.bean;

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

@ManagedBean
@SessionScoped
public class BackingBean {

    public BackingBean() {
        System.out.println("Constructor called");
    }

    public void init() {
        FacesContext fCtx = FacesContext.getCurrentInstance();
        String sessionId = fCtx.getExternalContext().getSessionId(false);
        System.out.println("Init called - session id: "+sessionId);
    }

    public String getText() {
        return "Some text";
    }
}

的pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0                 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.test</groupId>
    <artifactId>PrerenderViewTest</artifactId>
    <version>1.0-SNAPSHOT</version>
    <dependencies>
        <dependency>
            <groupId>javax.el</groupId>
            <artifactId>javax.el-api</artifactId>
            <version>3.0.0</version>
        </dependency>
        <dependency>
            <groupId>com.sun.faces</groupId>
            <artifactId>jsf-api</artifactId>
            <version>2.2.7</version>
        </dependency>

        <dependency>
            <groupId>com.sun.faces</groupId>
            <artifactId>jsf-impl</artifactId>
            <version>2.2.7</version>
        </dependency>

        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>jstl</artifactId>
            <version>1.2</version>
        </dependency>

    </dependencies>
</project>

的web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
         version="3.1">
    <servlet>
        <servlet-name>Faces Servlet</servlet-name>
        <servlet-class>javax.faces.webapp.FacesServlet</servlet-class>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>Faces Servlet</servlet-name>
        <url-pattern>*.xhtml</url-pattern>
    </servlet-mapping>

</web-app>

faces-config.xml中

<?xml version='1.0' encoding='UTF-8'?>
<faces-config version="2.2" xmlns="http://xmlns.jcp.org/xml/ns/javaee"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee 
    http://xmlns.jcp.org/xml/ns/javaee/web-facesconfig_2_2.xsd">

</faces-config>

我尝试了使用init()注释或@PostConstruct调用<f:event type="prerenderview" listener="#{backingBean.init}"/>的其他方法，但我得到的结果相同。当我访问页面时，init方法总是第一次被调用两次。在后续调用中，它只被调用一次。

JSF viewAction调用了两次

0 个答案: