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  • OSGi系列 《OSGi实战》之用户验证

    这两天看BlueDavy写的一篇OSGi入门的文章《OSGi实战》,在道客巴巴有这篇文章的链接。

    在这篇文章里面有这样一个例子:一个网站,有一个验证用户名和密码的页面(UserValidatorWebBundle)。验证的方式有三种:LDAP验证(LDAPValidatorBundle)﹑数据库验证(DBValidatorBundle)和配置文件验证(ConfigValidatorBundle)。在OSGi框架来讲,这分别是四个Bundle,UserValidatorWebBundle提供前端Web访问服务,执行时需要调用到三个验证Bundle中某一个提供的验证服务。三个验证Bundle在实际环境下可以通过启动其中一个﹑停止其它两个的方法实现动态的改变验证方式。

    另外,还有一个UserValidatorBundle,这个Bundle实际上只包含了一个验证服务的接口类,在LDAPValidatorBundle﹑DBValidatorBundle和ConfigValidatorBundle三个Bundle之间提供验证服务的公共定义。

    特别说明,我的开发环境是Eclipse JaveEE Indigo 3.7.2。

    实现UserValidatorBundle

    UserValidatorBundle提供验证服务的接口类Validator。由于它不要注册任何的服务和监听器,因此这里我们不需要为该Bundle提供Activator实现。它的作用就是将验证接口Validator通在MANIFEST.MF的Export-Package导出去,然后供其它具体实现验证服务的Bundle使用。

    Bundle的详细开发过程可以参考《OSGi系列 - 用Eclipse开发Bundle》,这里只对关键地方进行说明。

    UserValidatorBundle的目录结构,注意该Bundle没有Activator类:

    Validator.java文件内容:

    package org.riawork.demo.service.user;
    
    public interface Validator {
        public boolean validate(String username, String password) throws Exception;
    }

    打开MANIFEST.MF文件,在出现的元数据编辑页面中选择底部的Runtime标签页,然后点击Exported Packages旁边的Add...按钮,添加如下的内容:

    这个操作实际上就是在MANIFEST.MF文件里面增加一条Export-Package项目:

    Export-Package: org.riawork.demo.service.user

    MANIFEST.MF文件完整的内容:

    Manifest-Version: 1.0
    Bundle-ManifestVersion: 2
    Bundle-Name: UserValidatorBundle
    Bundle-SymbolicName: UserValidatorBundle
    Bundle-Version: 1.0.0
    Import-Package: org.osgi.framework;version="1.3.0"
    Bundle-RequiredExecutionEnvironment: JavaSE-1.6
    Export-Package: org.riawork.demo.service.user

    实现LDAPValidatorBundle

    LDAPValidatorBundle提供LDAP验证方式。

    LDAPValidatorBundle提供了一个LDAPValidator验证类,该类需要实现UserValidatorBundle里面的Valdiator接口,因此需要在MANIFEST.MF文件中通过Import-Package导入Validator接口所在的包org.riawork.demo.service.user。

    LDAPValidatorBundle同时也提供了一个LDAPActivator类,用来管理Bundle的生命周期,在start()和stop()方法中实现LDAPValidator验证服务的注册和卸载。

    作为演示用途,这里所有的验证方式都使用的是字符串硬编码的简单方式。

    LDAPValidatorBundle的目录结构:

    打开MANIFEST.MF文件,在出现的元数据编辑页面中选择底部的Dependencies标签页,然后点击Imported Packages旁边的Add...按钮,添加如下的内容:

    这个操作实际上就是在MANIFEST.MF文件里面增加一条Import-Package项目:

    Import-Package: org.osgi.framework;version="1.3.0",
     org.riawork.demo.service.user

    MANIFEST.MF文件完整的内容:

    Manifest-Version: 1.0
    Bundle-ManifestVersion: 2
    Bundle-Name: LDAPValidatorBundle
    Bundle-SymbolicName: LDAPValidatorBundle
    Bundle-Version: 1.0.0
    Bundle-Activator: org.riawork.demo.service.user.impl.LDAPActivator
    Import-Package: org.osgi.framework;version="1.3.0",
     org.riawork.demo.service.user
    Bundle-RequiredExecutionEnvironment: JavaSE-1.6

    LDAPValidator.java文件内容:

    package org.riawork.demo.service.user.impl;
    
    import org.riawork.demo.service.user.Validator;
    
    public class LDAPValidator implements Validator {
    
        public boolean validate(String username, String password) throws Exception {
            System.out.println("LDAPValidator.validate()方法被调用");
            
            if ("jerry".equals(username) && "jerry".equals(password)){
                return true;
            }
            
            return false;
        }
    
    }

    LDAPActivator.java文件内容:

    package org.riawork.demo.service.user.impl;
    
    import org.osgi.framework.BundleActivator;
    import org.osgi.framework.BundleContext;
    import org.osgi.framework.ServiceRegistration;
    import org.riawork.demo.service.user.Validator;
    
    public class LDAPActivator implements BundleActivator {
    
        private ServiceRegistration serviceReg = null;
    
        public void start(BundleContext bundleContext) throws Exception {
            System.out.println("LDAPValidator服务被注册");
            
            serviceReg = bundleContext.registerService(Validator.class.getName(), new LDAPValidator(), null);
        }
    
        public void stop(BundleContext bundleContext) throws Exception {
            if(serviceReg != null)
                serviceReg.unregister();
            
            System.out.println("LDAPValidator服务被卸载");
        }
    }

    实现DBValidatorBundle

    DBValidatorBundle提供数据库验证方式,该Bundle的实现方式完全同LDAPValidatorBundle。

    DBValidatorBundle的目录结构:

    MANIFEST.MF文件内容:

    Manifest-Version: 1.0
    Bundle-ManifestVersion: 2
    Bundle-Name: DBValidatorBundle
    Bundle-SymbolicName: DBValidatorBundle
    Bundle-Version: 1.0.0
    Bundle-Activator: org.riawork.demo.service.user.impl.DBActivator
    Import-Package: org.osgi.framework;version="1.3.0",
     org.riawork.demo.service.user
    Bundle-RequiredExecutionEnvironment: JavaSE-1.6

    DBValidator.java文件内容:

    package org.riawork.demo.service.user.impl;
    
    import org.riawork.demo.service.user.Validator;
    
    public class DBValidator implements Validator {
    
        public boolean validate(String username, String password) throws Exception {
            System.out.println("DBValidator.validate()方法被调用");
            
            if ("jerry".equals(username) && "jerry".equals(password)){
                return true;
            }
            
            return false;
        }
    }

    DBActivator.java文件内容:

    package org.riawork.demo.service.user.impl;
    
    import org.osgi.framework.BundleActivator;
    import org.osgi.framework.BundleContext;
    import org.osgi.framework.ServiceRegistration;
    import org.riawork.demo.service.user.Validator;
    
    public class DBActivator implements BundleActivator {
    
        private ServiceRegistration serviceReg = null;
    
        public void start(BundleContext bundleContext) throws Exception {
            System.out.println("DBValidator服务被注册");
            
            serviceReg = bundleContext.registerService(Validator.class.getName(), new DBValidator(), null);
        }
    
        public void stop(BundleContext bundleContext) throws Exception {
            if(serviceReg != null)
                serviceReg.unregister();
            
            System.out.println("DBValidator服务被卸载");
        }
    }

    实现ConfigValidatorBundle

    ConfigValidatorBundle提供配置人家验证方式,该Bundle的实现方式完全同LDAPValidatorBundle。

    ConfigValidatorBundle的目录结构:

    MANIFEST.MF文件内容:

    Manifest-Version: 1.0
    Bundle-ManifestVersion: 2
    Bundle-Name: ConfigValidatorBundle
    Bundle-SymbolicName: ConfigValidatorBundle
    Bundle-Version: 1.0.0
    Bundle-Activator: org.riawork.demo.service.user.impl.ConfigActivator
    Import-Package: org.osgi.framework;version="1.3.0",
     org.riawork.demo.service.user
    Bundle-RequiredExecutionEnvironment: JavaSE-1.6

    ConfigValidator.java文件内容:

    package org.riawork.demo.service.user.impl;
    
    import org.riawork.demo.service.user.Validator;
    
    public class ConfigValidator implements Validator {
    
        public boolean validate(String username, String password) throws Exception {
            System.out.println("ConfigValidator.validate()方法被调用");
            
            if ("jerry".equals(username) && "jerry".equals(password)){
                return true;
            }
            
            return false;
        }
    }

    ConfigActivator.java文件内容:

    package org.riawork.demo.service.user.impl;
    
    import org.osgi.framework.BundleActivator;
    import org.osgi.framework.BundleContext;
    import org.osgi.framework.ServiceRegistration;
    import org.riawork.demo.service.user.Validator;
    
    public class ConfigActivator implements BundleActivator {
    
        private ServiceRegistration serviceReg = null;
    
        public void start(BundleContext bundleContext) throws Exception {
            System.out.println("ConfigValidator服务被注册");
            
            serviceReg = bundleContext.registerService(Validator.class.getName(), new ConfigValidator(), null);
        }
    
        public void stop(BundleContext bundleContext) throws Exception {
            if(serviceReg != null)
                serviceReg.unregister();
            
            System.out.println("ConfigValidator服务被卸载");
        }
    }

    实现UserValidatorWebBundle

    UserValidatorWebBundle提供使用者前端访问。该Bundle提供一个login.html页面,输入用户名和密码后,点击登录按钮,将数据提交到LoginServlet。LoginServlet检查,获取已经注册的Validator验证服务,调用validate()方法检查传过来的用户名和密码是否正确。

    该Bundle使用到了Servlet API和HTTP服务,因此必需javax.servlet和org.eclipse.osgi.services两个额外的Bundle。

    UserValidatorWebBundle的目录结构:

    打开MANIFEST.MF文件,选择底部的Dependencies标签页,添加如下的内容:

    这个操作实际上就是在MANIFEST.MF文件里面增加Import-Package项目和Require-Bundle项目:

    Import-Package: org.osgi.framework;version="1.3.0",
     org.riawork.demo.service.user
    Require-Bundle: javax.servlet;bundle-version="2.5.0",
     org.eclipse.osgi.services;bundle-version="3.3.0"

    MANIFEST.MF文件完整的内容:

    Manifest-Version: 1.0
    Bundle-ManifestVersion: 2
    Bundle-Name: UserValidatorWebBundle
    Bundle-SymbolicName: UserValidatorWebBundle
    Bundle-Version: 1.0.0
    Bundle-Activator: org.riawork.demo.web.Activator
    Import-Package: org.osgi.framework;version="1.3.0",
     org.riawork.demo.service.user
    Bundle-RequiredExecutionEnvironment: JavaSE-1.6
    Require-Bundle: javax.servlet;bundle-version="2.5.0",
     org.eclipse.osgi.services;bundle-version="3.3.0"

    在src目录下新建page目录,然后在page目录下新增login.html文件。login.html文件内容:

    <HTML>
    <HEAD>
    <TITLE>OSGI Opendoc Demo</TITLE>
    <meta http-equiv="Content-Type" content="text/html;charset=utf-8" /> 
    <script>
    
        function login(){
            if(document.frmLogin.username.value==""){
                alert("必须输入用户名");
                document.frmLogin.username.focus();
                return;
            }
            if(document.frmLogin.userpass.value==""){
                alert("必须输入密码");
                document.frmLogin.userpass.focus();
                return;
            }
            document.frmLogin.submit();
        }
    
    </script>
    </HEAD>
    
    <BODY>
    <table style="45%;border:1px solid;height:100px">
        <form name=frmLogin method="post" action="/demo/login">
            <tr bgcolor="#C0C0C0">
                <td colspan="2" align="center">用户登录模块示例</td>
            </tr>
            <tr>
                <td width="30%">用户名</td>
                <td><input type="text" name="username" size="30"></td>
            </tr>
            <tr>
                <td>&nbsp;&nbsp;</td>
                <td><input type="password" name="userpass" size="33"></td>
            </tr>
            <tr bgcolor="#C0C0C0">
                <td colspan="2" align="center">
                    <input type=button name=btnSubmit value="登录" onclick="login();">
                </td>
            </tr>
        </form>
    </table>
    </BODY>
    </HTML>

    LoginServlet.java文件内容:

    package org.riawork.demo.web;
    
    import java.io.IOException;
    
    import javax.servlet.ServletOutputStream;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    
    import org.osgi.framework.BundleContext;
    import org.osgi.framework.ServiceReference;
    import org.riawork.demo.service.user.Validator;
    
    public class LoginServlet extends HttpServlet {
    
        private static final long serialVersionUID = 1L;
        
        private BundleContext context;
        
        public LoginServlet(BundleContext context){
            this.context=context;
        }
        
        /** 
         * Web Post Method 
         */
        public void doPost(HttpServletRequest request,  HttpServletResponse response)
                  throws IOException{
            doGet(request, response);
        }
    
        /** 
         * Web GET Method 
         */
        public void doGet(HttpServletRequest request,  HttpServletResponse response)
            throws IOException{
            String username=request.getParameter("username");
            String userpass=request.getParameter("userpass");
            response.setContentType("text/html");
            ServletOutputStream output=response.getOutputStream();
            ServiceReference serviceRef=context.getServiceReference(Validator.class.getName());
            Validator validator=(Validator) context.getService(serviceRef);
            if(validator==null){
                output.println("No usable validator service");
                output.close();
                return;
            }
            boolean result=false;
            try {
                result=validator.validate(username, userpass);
                if(result)
                    output.println("Login success");
                else
                    output.println("Login Fail,please check username and password");
                output.close();
                return;
            } 
            catch (Exception e) {
                output.println("Login error:");
                output.println(e.toString());
                return;
            }
        }
    
    }

    Activator.java文件内容:

    package org.riawork.demo.web;
    
    import javax.servlet.Servlet;
    
    import org.osgi.framework.BundleActivator;
    import org.osgi.framework.BundleContext;
    import org.osgi.framework.ServiceEvent;
    import org.osgi.framework.ServiceListener;
    import org.osgi.framework.ServiceReference;
    import org.osgi.service.http.HttpService;
    import org.riawork.demo.web.LoginServlet;
    
    public class Activator implements BundleActivator,ServiceListener{
    
        private BundleContext bc;
        private ServiceReference ref;
        private Servlet servlet;
    
        public void start(BundleContext context) throws Exception {
            bc=context;
            servlet=new LoginServlet(bc);
            registerServlet();
            context.addServiceListener(this, "(objectClass=" + HttpService.class.getName() + ")");
        }
    
        public void stop(BundleContext context) throws Exception {
            try {
                unregisterServlet();
            } catch (Throwable t) {
                t.printStackTrace();
            }
    
            servlet = null;
            bc = null;
            ref = null;
        }
    
        public void serviceChanged(ServiceEvent event) {
            switch (event.getType()){
                case ServiceEvent.REGISTERED:
                    registerServlet();
                    break;
    
                case ServiceEvent.UNREGISTERING:
                    unregisterServlet();
                    break;
            }
        }
        
        private void registerServlet() {
            if (ref == null)
                ref = bc.getServiceReference(HttpService.class.getName());
         
            if (ref != null) {
                try {
                    HttpService http = (HttpService) bc.getService(ref);
                    http.registerServlet("/demo/login", servlet, null, null);
                    http.registerResources("/demo/page","page",null);
                    System.out.println("已启动用户登录验证web模块,请通过/demo/page/login.htm访问");
                } 
                catch (Exception e) {
                    e.printStackTrace();
                }
            }
        }
        
        private void unregisterServlet() {
            if (ref != null) {
                try {
                    HttpService http = (HttpService) bc.getService(ref);
                    http.unregister("/demo/login");
                    http.unregister("/demo/page");
                    System.out.println("已卸载用户登录验证web模块!");
                }
                catch(Exception e){
                    e.printStackTrace();
                }
            }
        }
    }

    创建OSGi Run Configuration

    选择菜单Run >> Run Configurations...,在弹出的Run Configurations对话框左边找到OSGi Framework,在该项目上点击鼠标右键选择New菜单项,画面如下:

    下表的Bundle在Run Configurations对话框中必须被选中:

    • UserValidatorBundle
    • LDAPValidatorBundle
    • DBValidatorBundle
    • ConfigValidatorBundle
    • UserValidatorWebBundle
    • javax.servlet
    • org.eclipse.osgi.services
    • org.eclipse.equinox.http.servlet
    • org.eclipse.equinox.http.jetty
    • org.mortbay.jetty.server
    • org.mortbay.jetty.util

    配置完毕后,点击右下角的Run按钮,启动OSGi框架。如果一切正常,就会出现osgi>提示符,以及Bundle被启动时输出的提示信息:

    从上图我们应该发现一个问题,实际上三个不同的验证方式都被启动了。

    动态的切换验证方式

    打开浏览器,输入http://localhost/demo/page/login.html,出现输入用户名和密码画面:

    输入一个用户名和密码(正确的是jerry和jerry),点击登录按钮,浏览器网址转到了http://localhost/demo/login,这实际上就是我们注册的LoginServlet(参考UserValidatorWebBundle的Activator.java文件)。

    请注意,这个时候我们查看OSGi控制台,有看到一条信息“ConfigValidator.validate()方法被调用”,说明当前使用的验证方式是配置文件验证。因为我们提供的三种验证服务都被启动了,换句话说,在OSGi框架中,Validator服务有三个提供者,在服务被调用时具体用的是哪一个提供者会由OSGi框架随机的决定。

    停止Config和DB验证,只启动LDAP验证,然后再次提交http://localhost/demo/page/login.html,观察OSGi控制台,发现这次使用的是LDAP验证。

    停止LDAP和Config验证,启动DB验证,观察OSGi控制台,是不是就是我们所期望的DB验证?

    这篇文章实在是有点太长了,对于没耐心从头看到尾的朋友,下面提供了一个压缩文件下载链接,希望能帮助你省一点点时间。

    https://files.cnblogs.com/eastson/osgi-user-valiator-code.rar

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  • 原文地址:https://www.cnblogs.com/eastson/p/2504004.html
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