Spring集成（Spring Integration）

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2023-12-01

Spring提供了特殊的类DelegatingVariableResolver，以无缝方式将JSF和Spring集成在一起。

在JSF中集成Spring依赖注入（IOC）功能需要以下步骤。

第1步:添加DelegatingVariableResolver

在faces-config.xml中添加一个variable-resolver条目，指向spring类DelegatingVariableResolver 。

<faces-config>
   <application>
   <variable-resolver>
      org.springframework.web.jsf.DelegatingVariableResolver
   </variable-resolver>
   ...
</faces-config>

第2步:添加上下文监听器

在web.xml中添加spring框架提供的ContextLoaderListener和RequestContextListener监听器。

<web-app>
   ...
   <!-- Add Support for Spring -->
   <listener>
      <listener-class>
         org.springframework.web.context.ContextLoaderListener
      </listener-class>
   </listener>
   <listener>
      <listener-class>
         org.springframework.web.context.request.RequestContextListener
      </listener-class>
   </listener>
   ...
</web-app>

第3步:定义依赖关系

在applicationContext.xml中定义bean，它将用作托管bean中的依赖项。

<beans>
   <bean id = "messageService" 
      class = "cn.xnip.test.MessageServiceImpl">
      <property name = "message" value = "Hello World!" />        
   </bean>
</beans>

第4步:添加依赖项

DelegatingVariableResolver首先将值查找委托给JSF的默认解析器，然后委托给Spring的WebApplicationContext。这允许人们轻松地将基于spring的依赖项注入到一个JSF管理的bean中。

我们在这里注入了messageService作为基于spring的依赖。

<faces-config>
   ...
   <managed-bean>
      <managed-bean-name>userData</managed-bean-name>
      <managed-bean-class>cn.xnip.test.UserData</managed-bean-class>
      <managed-bean-scope>request</managed-bean-scope>
      <managed-property>
         <property-name>messageService</property-name>
         <value>#{messageService}</value>
      </managed-property>
   </managed-bean> 
</faces-config>

第5步:使用依赖关系

//jsf managed bean
public class UserData {
   //spring managed dependency
   private MessageService messageService;
   public void setMessageService(MessageService messageService) {
      this.messageService = messageService;
   }
   public String getGreetingMessage() {
      return messageService.getGreetingMessage();
   }
}

例子 Example Application

让我们创建一个测试JSF应用程序来测试spring集成。

步	描述
1	在cn.xnip.test包下创建一个名为helloworld的项目，如JSF - First Application一章中所述。
2	修改pom.xml ，如下所述。
3	在WEB-INF文件夹中创建faces-config.xml ，如下所述。
4	修改web.xml ，如下所述。
5	在WEB-INF文件夹中创建applicationContext.xml ，如下所述。
6	在包cn.xnip.test下创建MessageService.java ，如下所述。
7	在包cn.xnip.test下创建MessageServiceImpl.java ，如下所述。
8	在包cn.xnip.test下创建UserData.java ，如下所述。
9	修改home.xhtml ，如下所述。保持其余文件不变。
10	编译并运行应用程序以确保业务逻辑按照要求运行。
11	最后，以war文件的形式构建应用程序并将其部署在Apache Tomcat Webserver中。
12	使用适当的URL启动Web应用程序，如下面的最后一步所述。

pom.xml

<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/maven-v4_0_0.xsd">
   <modelVersion>4.0.0</modelVersion>
   <groupId>cn.xnip.test</groupId>
   <artifactId>helloworld</artifactId>
   <packaging>war</packaging>
   <version>1.0-SNAPSHOT</version>
   <name>helloworld Maven Webapp</name>
   <url>http://maven.apache.org</url>
   <dependencies>
      <dependency>
         <groupId>junit</groupId>
         <artifactId>junit</artifactId>
         <version>3.8.1</version>
         <scope>test</scope>
      </dependency>
      <dependency>
         <groupId>com.sun.faces</groupId>
         <artifactId>jsf-api</artifactId>
         <version>2.1.7</version>
      </dependency>
      <dependency>
         <groupId>com.sun.faces</groupId>
         <artifactId>jsf-impl</artifactId>
         <version>2.1.7</version>
      </dependency>
      <dependency>
         <groupId>javax.servlet</groupId>
         <artifactId>jstl</artifactId>
         <version>1.2</version>
      </dependency>
      <dependency>
         <groupId>org.springframework</groupId>
         <artifactId>spring-core</artifactId>
         <version>3.1.2.RELEASE</version>
      </dependency>
      <dependency>
         <groupId>org.springframework</groupId>
         <artifactId>spring-web</artifactId>
         <version>3.1.2.RELEASE</version> 
      </dependency>
   </dependencies>
   <build>
      <finalName>helloworld</finalName>
      <plugins>
         <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>2.3.1</version>
            <configuration>
               <source>1.6</source>
               <target>1.6</target>
            </configuration>
         </plugin>
         <plugin>
            <artifactId>maven-resources-plugin</artifactId>
            <version>2.6</version>
            <executions>
               <execution>
                  <id>copy-resources</id>
                  <phase>validate</phase>
                  <goals>
                     <goal>copy-resources</goal>
                  </goals>
                  <configuration>
                     <outputDirectory>${basedir}/target/helloworld/resources
                        </outputDirectory>
                     <resources>          
                        <resource>
                           <directory>src/main/resources</directory>
                           <filtering>true</filtering>
                        </resource>
                     </resources>              
                  </configuration>            
               </execution>
            </executions>
         </plugin>
      </plugins>
   </build>
</project>

faces-config.xml

<?xml version = "1.0" encoding = "UTF-8"?>
<faces-config
   xmlns = "http://java.sun.com/xml/ns/javaee"
   xmlns:xsi = "http://www.w3.org/2001/XMLSchema-instance"
   xsi:schemaLocation = "http://java.sun.com/xml/ns/javaee 
   http://java.sun.com/xml/ns/javaee/web-facesconfig_2_0.xsd"
   version = "2.0"> 
   <application>
      <variable-resolver>
         org.springframework.web.jsf.DelegatingVariableResolver
      </variable-resolver>
   </application>
   <managed-bean>
      <managed-bean-name>userData</managed-bean-name>
      <managed-bean-class>cn.xnip.test.UserData</managed-bean-class>
      <managed-bean-scope>request</managed-bean-scope>
      <managed-property>
         <property-name>messageService</property-name>
         <value>#{messageService}</value>
      </managed-property>
   </managed-bean> 
</faces-config>

web.xml

<!DOCTYPE web-app PUBLIC
   "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
   "http://java.sun.com/dtd/web-app_2_3.dtd" >
<web-app>
   <display-name>Archetype Created Web Application</display-name>
   <context-param>
      <param-name>javax.faces.PROJECT_STAGE</param-name>
      <param-value>Development</param-value>
   </context-param>	
   <!-- Add Support for Spring -->
   <listener> 
      <listener-class>
         org.springframework.web.context.ContextLoaderListener
      </listener-class>
   </listener>
   <listener>
      <listener-class>
         org.springframework.web.context.request.RequestContextListener
      </listener-class>
   </listener>
   <servlet>
      <servlet-name>Faces Servlet</servlet-name>
      <servlet-class>javax.faces.webapp.FacesServlet</servlet-class>
   </servlet>
   <servlet-mapping>
      <servlet-name>Faces Servlet</servlet-name>
      <url-pattern>*.jsf</url-pattern>
   </servlet-mapping>
</web-app>

applicationContext.xml

<?xml version = "1.0" encoding = "UTF-8"?>
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN 2.0//EN" 
   "http://www.springframework.org/dtd/spring-beans-2.0.dtd">
<beans>
   <bean id = "messageService" 
      class = "cn.xnip.test.MessageServiceImpl">
      <property name = "message" value = "Hello World!" />        
   </bean>
</beans>

MessageService.java

package cn.xnip.test;
public interface MessageService {
   String getGreetingMessage();
}

MessageServiceImpl.java

package cn.xnip.test;
public class MessageServiceImpl implements MessageService {
   private String message;
   public String getGreetingMessage() {
      return message;
   }
   public String getMessage() {
      return message;
   }
   public void setMessage(String message) {
      this.message = message;
   }
}

UserData.java

package cn.xnip.test;
import java.io.Serializable;
public class UserData implements Serializable {
   private static final long serialVersionUID = 1L;
	private MessageService messageService;
   public MessageService getMessageService() {
      return messageService;
   }
   public void setMessageService(MessageService messageService) {
      this.messageService = messageService;
   }
   public String getGreetingMessage() {
      return messageService.getGreetingMessage();
   }
}

home.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:head>
      <title>JSF Tutorial!</title>
   </h:head>
   <h:body>
      <h2>Spring Integration Example</h2>
      #{userData.greetingMessage}
   </h:body>
</html>

一旦准备好完成所有更改，让我们像在JSF - First Application章节中那样编译和运行应用程序。如果您的应用程序一切正常，这将产生以下结果。