Extreme Pattern

源起

除了直接接到 spring MVC 來展現網頁之外，對於外部的程式也需要連結，這裡測試 XFire 掛 Spring 的模式來做。

XFire

Chapter 17.5. Web Services

XFire Spring support

XFire JSR 181 Annotations

做法

xfire 有支援 spring ，他將一些預設定義放在 classpath:org/codehaus/xfire/spring/xfire.xml， 不過它是 spring 1.x 版本，即使設定 eclipse buddy 機制取得這個檔，也需要修改，索性直接將這個 檔放到需要的包中。

主要實做下面幾包 bundle 來用。

1. haha.remix.xfire
2. haha.hello.ws.userdao
3. haha.hello.ws.client

haha.remix.xfire

這是個大轉包，沒有加程式，只是改 MANIFEST.MF 來協助。

Manifest-Version: 1.0
Bundle-ManifestVersion: 2
Bundle-Name: haha.remix.xfire
Bundle-SymbolicName: haha.remix.xfire
Bundle-Version: 1.0.0
Bundle-Activator: haha.remix.xfire.Activator
Bundle-Localization: plugin
Import-Package: javax.servlet;version="2.4.0",
 javax.servlet.http;version="2.4.0",
 org.apache.commons.logging,
 org.osgi.framework;version="1.3.0" 
Bundle-ClassPath: lib/wstx-asl-3.1.0.jar,
 lib/stax-api-1.0.1.jar,
 lib/wsdl4j-1.5.2.jar,
 lib/xfire-all-1.2.2.jar,
 lib/xfire-jsr181-api-1.0-M1.jar,
 .,
 lib/activation-1.1.jar,
 lib/jdom-1.0.jar,
 lib/XmlSchema-1.1.jar
Export-Package: com.ctc.wstx.stax,
 javax.jws,
 javax.xml.stream,
 org.apache.ws.commons.schema,
 org.codehaus.stax2,
........[skip]
Require-Bundle: org.apache.commons.httpclient;resolution:=optional,
 org.apache.commons.codec;resolution:=optional,
 haha.remix.spring;resolution:=optional

這裡需注意 require bundle 都是選擇性的，那是因為有些特定需求要到客端包要求的時候，才會需要， 也不一定會有這些客端包，所以一直掛著讓他一定要這個附屬包也說不過去，所以用選擇性掛上。

haha.hello.ws.userdao

META-INF/spring/bean.xml

<osgi:reference id="httpService" 
  interface="org.osgi.service.http.HttpService"/>

<bean name="servletRegister" 
   class="haha.hello.ws.userdao.ServletRegister" init-method="init">
      <property name="httpService" ref="httpService"/>
</bean>

haha.hello.ws.userdao.ServletRegister 負責啟動 WEB-INF/xx.xml 與註冊服務到 osgi:reference 的 org.osgi.service.http.HttpService

System.setProperty("javax.xml.stream.XMLInputFactory",
  "com.ctc.wstx.stax.WstxInputFactory");
System.setProperty("javax.xml.stream.XMLOutputFactory",
  "com.ctc.wstx.stax.WstxOutputFactory");
System.setProperty("javax.xml.stream.XMLEventFactory",
  "com.ctc.wstx.stax.WstxEventFactory");

DispatcherServlet servlet = new DispatcherServlet();
servlet.setNamespace("hello-servlet");

OsgiWebApplicationContext owac = new OsgiWebApplicationContext();
servlet.setContextClass(owac.getClass());
httpService.registerServlet("/services", servlet, null ,null);

WEB-INF/hello-servlet.xml

<import resource="xfire.xml"/>
<osgi:reference id="userDao" 
     interface="haha.hello.jpa.userdao.UserDao"/>

<bean name="helloImpl" class="haha.hello.ws.userdao.HelloImpl">     
   <property name="userDao" ref="userDao"/>
</bean>

<bean class="org.springframework.web.servlet.handler.SimpleUrlHandlerMapping">
   <property name="mappings">
            <value>/hello=wsController</value>
   </property>
</bean>

<bean id="wsController" 
      class="org.codehaus.xfire.spring.remoting.XFireExporter">
        <property name="serviceFactory">
            <ref bean="xfire.annotationServiceFactory"/>
        </property>
        <property name="xfire">
            <ref bean="xfire"/>
        </property>
        <property name="serviceBean">
            <ref bean="helloImpl"/>
        </property>
</bean>

WEB-INF/xfire.xml 取自 xfire classpath:org/codehaus/xfire/spring/xfire.xml 修改一下 singleton 設定而已。

這一包主要將 haha.hello.ws.userdao.Hello 放到 WebServic 去。

haha.hello.ws.userdao.Hello

package haha.hello.ws.userdao;

import javax.jws.WebMethod;
import javax.jws.WebResult;
import javax.jws.WebService;

@WebService(name = "HelloService",  targetNamespace = "http://www.openuri.org/2004/04/HelloWorld")
public interface Hello {
  @WebMethod
  @WebResult
  String getName();
}

haha.hello.ws.userdao.HelloImpl 會注入 osgi:reference 的 haha.hello.jpa.userdao.UserDao 來用。

package haha.hello.ws.userdao;

import haha.hello.jpa.userdao.UserDao;
import javax.jws.WebService;

@WebService(endpointInterface = "haha.hello.ws.userdao.Hello")
public class HelloImpl implements Hello {

 private UserDao userDao;

 private String name = "foo";

 public String getName() {
   return name + userDao.loadUsers().size();
 }
....[SKIP].....

MANIFEST.MF

Manifest-Version: 1.0
Bundle-ManifestVersion: 2
Bundle-Name: haha.hello.ws.userdao
Bundle-SymbolicName: haha.hello.ws.userdao
Bundle-Version: 1.0.0
Bundle-Activator: haha.hello.ws.userdao.Activator
Bundle-Localization: plugin
Import-Package: com.ctc.wstx.stax,
 javax.jws,
 javax.servlet;version="2.4.0",
 javax.servlet.http;version="2.4.0",
 org.osgi.framework;version="1.3.0",
 org.osgi.service.http;version="1.2.0",
 org.springframework.osgi.context.support
Require-Bundle: haha.remix.spring,
 org.eclipse.equinox.http.jetty,
 haha.hello.jpa.userdao,
 haha.remix.xfire
Export-Package: haha.hello.ws.userdao

啟動後可以直接開瀏覽器到 http://127.0.0.1/services/hello?wsdl 觀察 WSDL。

haha.hello.ws.client

陽春型客戶端，只是取用 getName 輸出看看而已，沒有用到 WSDL2JAVA 來轉成 java。

package haha.hello.ws.client;

import java.net.URL;
import org.codehaus.xfire.client.Client;
import org.osgi.framework.BundleActivator;
import org.osgi.framework.BundleContext;

public class Activator implements BundleActivator {

 public void start(BundleContext context) throws Exception {
    Client client = new Client(
            new URL("http://127.0.0.1/services/hello?wsdl"));
        Object[] results = client.invoke("getName",null);
        System.out.println(results[0]);
 }
...[SKIP]....

MANIFEST.MF

Manifest-Version: 1.0
Bundle-ManifestVersion: 2
Bundle-Name: haha.hello.ws.client
Bundle-SymbolicName: haha.hello.ws.client
Bundle-Version: 1.0.0
Bundle-Activator: haha.hello.ws.client.Activator
Bundle-Localization: plugin
Import-Package: org.apache.commons.logging,
 org.codehaus.xfire.client,
 org.osgi.framework;version="1.3.0" 
Bundle-ClassPath: .
Require-Bundle: org.apache.commons.httpclient,
 org.apache.commons.codec,
 haha.hello.ws.userdao,
 haha.remix.xfire

觀察

1. 越深入企業層面的應用，越發覺既有程式套件之間的相依性很高，之前用一個 classpath 可以找到， 現在轉 OSGi 變成要考慮匯出匯入問題，變的更為複雜，有時現有套件無法滿足，只好直接轉 remix 大包 來實現或是用 eclipse buddy 機制。
2. 如果使用 import-package 方式，似乎無法保證某些服務會先啟動，於是將 ws.client 中設定 Require-Bundle 來讓某些服務先滿足。