带JSF的Spring Boot；找不到工厂javax.faces.context.facescontextFactory的备份

Question

我在使用Spring Boot和JSF时遇到了一些问题。servlet似乎可以正确启动，但当我试图访问资源时，会出现以下异常

java.lang.IllegalStateException: Could not find backup for factory javax.faces.context.FacesContextFactory. 
    at javax.faces.FactoryFinder$FactoryManager.getFactory(FactoryFinder.java:1011)
    at javax.faces.FactoryFinder.getFactory(FactoryFinder.java:343)
    at javax.faces.webapp.FacesServlet.init(FacesServlet.java:302)
    at org.apache.catalina.core.StandardWrapper.initServlet(StandardWrapper.java:1284)
    at org.apache.catalina.core.StandardWrapper.allocate(StandardWrapper.java:884)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:134)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501)
    at org.apache.catalina.valves.RemoteIpValve.invoke(RemoteIpValve.java:683)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1040)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:607)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1720)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1679)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:724)

我的应用程序类如下

@Configuration
@EnableAutoConfiguration
@ComponentScan
public class Application extends SpringBootServletInitializer {

    public static void main(String[] args) {
        SpringApplication.run(Application.class);
    }

    @Override
    protected SpringApplicationBuilder configure(SpringApplicationBuilder application) {
        return application.sources(Application.class);
    }

    @Bean
    public FacesServlet facesServlet() {
        return new FacesServlet();
    }

    @Bean
    public ServletRegistrationBean facesServletRegistration() {
        ServletRegistrationBean registration = new ServletRegistrationBean(
            facesServlet(), "*.xhtml");
        registration.setName("Christmas");
        return registration;
    }

    @Bean
    public ServletListenerRegistrationBean<ConfigureListener> jsfConfigureListener() {
        return new ServletListenerRegistrationBean<ConfigureListener>(
            new ConfigureListener());
    }
}

<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.x.y.z</groupId>
    <artifactId>project</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.1.5.RELEASE</version>
    </parent>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.primefaces</groupId>
            <artifactId>primefaces</artifactId>
            <version>5.0</version>
        </dependency>

        <!-- JSF 2 -->
        <dependency>
            <groupId>com.sun.faces</groupId>
            <artifactId>jsf-api</artifactId>
            <version>2.1.11</version>
        </dependency>

        <dependency>
            <groupId>com.sun.faces</groupId>
            <artifactId>jsf-impl</artifactId>
            <version>2.1.11</version>
        </dependency>
    </dependencies>

</project>

Answer 1

要使JSF在没有web.xml或faces-config.xml的情况下工作于Spring Boot，需要通过ServletContext上的init参数强制它加载配置文件。一种简单的方法是实现ServletContextAware:

public class Application implements ServletContextAware {

    // ...

    @Override
    public void setServletContext(ServletContext servletContext) {
        servletContext.setInitParameter("com.sun.faces.forceLoadConfiguration", Boolean.TRUE.toString());           
    }
}

JSF的configureListener也依赖于JSP，因此您需要在POM中添加一个对Jasper的依赖：

<dependency>
    <groupId>org.apache.tomcat.embed</groupId>
    <artifactId>tomcat-embed-jasper</artifactId>
</dependency>

它与您的问题没有直接关系，但您不需要将facesservlet声明为bean。ServletRegistrationBean就足够了。

这使得application.java如下所示：

import javax.faces.webapp.FacesServlet;
import javax.servlet.ServletContext;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.context.embedded.ServletListenerRegistrationBean;
import org.springframework.boot.context.embedded.ServletRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.context.ServletContextAware;

import com.sun.faces.config.ConfigureListener;

@Configuration
@EnableAutoConfiguration
@ComponentScan
public class Application implements ServletContextAware {

    public static void main(String[] args) {
        SpringApplication.run(Application.class);
    }

    @Bean
    public ServletRegistrationBean facesServletRegistration() {
        ServletRegistrationBean registration = new ServletRegistrationBean(
            new FacesServlet(), "*.xhtml");
        registration.setLoadOnStartup(1);
        return registration;
    }

    @Bean
    public ServletListenerRegistrationBean<ConfigureListener> jsfConfigureListener() {
        return new ServletListenerRegistrationBean<ConfigureListener>(
            new ConfigureListener());
    }

    @Override
    public void setServletContext(ServletContext servletContext) {
        servletContext.setInitParameter("com.sun.faces.forceLoadConfiguration", Boolean.TRUE.toString());       
    }
}