基于Java代理和HTTP协议的RMI框架的实现

代理模式为其他对象提供一种代理以控制对目标对象的访问,Java动态代理则为代理模式提供了一种简单易用的框架.基于HTTP协议的Tava对象隧道技术实现对象消息传递,可以方便地把这个技术集成到应用系统中.在介绍Java代理模式和基于HTTP协议的Java对象隧道技术的基础上,提出了基于二者的一种RMI框架的设计与实现.该框架不但可以穿越企业内外网防火墙,而且使得部署RMI应用与普通Web应用一样简单.     

基于动态代理的Java远程调用框架的研究

随着网络技术的发展,越来越多的项目采用了分布式的系统架构.对于这些把系统中的任务分配到不同计算机的架构来说,采用哪种方式在系统中不同的计算机之间进行通信十分重要.提出了一种基于动态代理的Java远程调用框架.利用此框架可以使远端的Java应用程序之间的调用更加简单、灵活、高效,同时也可以通过加入插入式代码的方式扩充对远程调用的自定义管理.     

基于移动代理的网络入侵预警框架

本文采用移动代理实现网络入侵预警框架，通过基本入侵检测模块获得可疑安全事件，动态分派相关移动代理收集进一步的入侵事件，构造基于入侵事件的有限自动机预警模型，预测下一步的入侵事件和可能的入侵攻击，降低误报率。同时，通过移动代理降低了网络通信量和系统负载。     

动态代理研究与实现

动态代理的基本思想就是建立一个可以返回动态代理对象的代理工厂,该代理工厂提供一个静态方法,用户自己的业务处理对象和系统服务对象传递给该代理工厂,在代理工厂的内部,通过反射技术,获得该业务逻辑对象的类对象,从而自动的拼装一个业务逻辑类的子类,在该子类中,代理工厂自己完成我们业务逻辑和系统服务的动态拼装,然后代理工厂动态编译该类,动态生成该代理类的对象,返回代理对象给客户,从而实现了真正意义上的业务逻辑和系统服务逻辑之间的动态组装。     

一个基于对象代理模型的多表现地理信息系统

文中提出了一种基于对象代理模型的实现多表现GIS的新方法。通过地理对象的代理对象来定义多表现，因此代理对象可以用来表示对象的视角多样性和角色多样性。通过对象更新迁移可以支持动态分类和系统一致性维护。另外，对象及其代理对象之间的双向指针使得跨类查询变得非常容易，从而可以扩展查询的范围。文中实现了一个基于对象代理模型的多表现GIS原型，性能测试表明该方法比传统的方法更加有效。     

一种通用的EJB方法调用框架的设计与实现

首先介绍动态代理和基于Java反射的方法调用,然后从设计和实现两个方面讨论了一种通用的EJB方法调用框架。     

基于Java卡的移动代理系统安全模型

本文给出一个基于Java卡自行开发的移动代理系统JC-MAS，并从通信过程、主机执行环境和代理程序三方面研究系统安全策略，针对使用Java卡构建的JC-MAS安全模型设计了详细解决方案。     

基于代理技术的LD-IDS任务分派机制研究

代理和移动代理具有自治性、智能性、移动性等特点,可相对独立地完成一项任务。将代理技术应用于大规模分布式入侵检测系统的实现中,提出了可应用于LDIDS的任务分派机制,该机制实现对移动代理的使用和管理。给出了机制模型,描述了任务分派机制的具体步骤,并对实现该机制过程中所涉及的关键技术进行了讨论。     

问与答

问:Java Beans组件是什么? 答:Java Beans是一种可重用的软件组件,并可在组件框架中被可视化地操纵。Java Beans组件模型并没有修改Java语言的语法和语义,开发人员在制作一个Java Beans组件时仅需遵循一定的命名和设计规范。同时,Jana Beans组件模型为开发人员提供了一整套APls(Jana Beans包)来对组件进行描述,这是组件和框架互操作的基础,框架可根据组件描述来操作动态加载在框架中的所有组件,如定制组件的属性、调整组件的位置、设计不同组件间的交互、等等。问:Java Beans组件模型可以提供哪些服务? 答:Java Beans可提供的服务总体来说有以下六种: 1.组件接口的公开和发现。这是组件接口的公开机制,通过公开出来的接口,其他组件或框架环境通过方法调用或者事件传递来驱动组件。 2.事件处理:事件处理是组件产生并广播事件的机制,通过这种机制,事件传递到特定组件上,被通知的组件执行相应的事     

基于Java-RMI技术的移动代理系统设计

移动代理是一种新型的分布式计算技术，有着许多传统分布式计算模型无法比拟的优势，是目前研究和应用热点。RMI（远程方法调用）是Java平台解决远程调用的方案，基于RMI技术设计了移动代理系统，对移动代理系统的关键问题进行了分析，通过RMI技术和动态类加载技术实现了移动代理系统，并设计实验验证了移动代理的移动性和自主性。     

Solving the Java object storage problem

Today's Internet driven view of information systems is helping to popularize Java as an application development language. Developers are beginning to use Java to create multi tier application architectures that often integrate relational data stores with new data types, in order to package information in easier to use, dynamic ways. Java's object oriented nature is ideally suited to this new world. Using objects, Java developers can encapsulate both data and data manipulation methods to give applications a runtime dynamism and self-contained intelligence that is difficult to achieve using other methods. Java application developers need to be able to store these Java objects-technically, to give them persistence-in order to take advantage of these capabilities. We examine the development issues surrounding Java object storage, including a brief overview of the ODMG Java binding, a standard that adds object persistence to Java. We compare this with the much greater level of effort required to implement the same application using the lower level JDBC interface, which supports Java object storage in relational databases. The ODMG binding for Java and JDBC are not competitive specifications: ODMG interfaces can be built on top of JDBC     

MS-3监测系统对Java多线程程序的监测

多线程是Java语言的重要特点之一，但是Java语言的线程调度是由操作系统来完成的，开发人员无法获知各线程的具体执行情况，而常规的软件调试工具对线程的分析会对目标程序有较大的干扰。该文利用基干事件的混合监测系统MS-3，对Java多线程程序的各线程行为进行了精确的分析。     

Java Native Interface idioms for C++ class hierarchies

The Java^TM Native Interface (JNI) provides a set of mechanisms for implementing Java methods in C or C++. JNI is useful for reusing C and C++ code repositories within Java frameworks. JNI is also useful for real‐time systems, where compiled C/C++ code executes performance‐critical tasks, while Java code executes system control and feature tasks. Available JNI literature concentrates on creating Java proxy classes that allow Java clients to interact with C++ classes. Current JNI literature does not discuss Java proxies for entire C++ inheritance hierarchies; that is the topic of this paper. Our experience in reusing C++ class hierarchies within a Java framework has uncovered a set of useful techniques for constructing Java proxy class hierarchies that mirror their C++ counterparts. This report gives both high level design guidelines and specific programming idioms for constructing Java class hierarchies that serve as proxies for C++ counterparts. We begin by discussing opportunities for reuse within a proxy class hierarchy, as well as problems caused by differences between the Java and C++ approaches to inheritance. The two most significant differences are due to C++ support for invocation of a member function based on the static type of its class, and C++ support for multiple implementation inheritance. Two example C++ class hierarchies provide the basis for a set of sections that present the design guidelines and that codify the programming idioms. This work could serve as the basis for an automatic generator of Java proxy class hierarchies. Copyright © 2000 John Wiley & Sons, Ltd.     

关于Java类加载器的探讨

Java的类加载机制是Java技术体系中比较核心的部分,这种机制虽然不和开发人员直接接触,但是如果对其背后的机理有一定理解的话,有助于开发人员排查程序中出现的类加载失败等技术问题,对理解Java虚拟机的连接模型和Java语言的动态性都有很大帮助。     

Babylon: middleware for distributed,parallel, and mobile Java applications

Babylon is a collection of tools and services that provide a 100% Java‐compatible environment for developing, running and managing parallel, distributed and mobile Java applications. It incorporates features such as object migration, asynchronous method invocation, and remote class loading, while providing an easy‐to‐use interface. Additionally, Babylon enables Java applications to seamlessly create and interact with remote objects, while protecting those objects from other applications by implementing access restrictions and separate namespaces. The implementation of Babylon centers around dynamic proxies, a feature first available in Java 1.3, that allow proxy objects to be created at runtime. Dynamic proxies play a key role in achieving the goals of Babylon. The potential cluster computing benefits of the system are demonstrated with experimental results, which show that sequential Java applications can achieve significant performance benefits from using Babylon to parallelize their work across a cluster of workstations. Copyright © 2008 John Wiley & Sons, Ltd.     

利用Hibernate对象持久化服务简化Java数据库访问

Hibernate是一个对象持久化工具，它通过其强大的O／R映射功能将Java对象同存放于关系数据库中的数据进行映射，避免了开发人员使用大量的SQL语句通过JDBC的方式对数据库进行操作，可以有效地提高开发的效率。将其应用于网络报表系统中，可充分利用其优点。     

ID-based proxy signature scheme with message recovery

A proxy signature scheme, introduced by Mambo, Usuda and Okamoto, allows an entity to delegate its signing rights to another entity. Identity based public key cryptosystems are a good alternative for a certificate based public key setting, especially when efficient key management and moderate security are required. From inception several ID-based proxy signature schemes have been discussed, but no more attention has been given to proxy signature with message recovery. In this paper, we are proposing provably secure ID-based proxy signature scheme with message recovery and we have proved that our scheme is secure as existential forgery-adaptively chosen message and ID attack. As proposed scheme is efficient in terms of communication overhead and security, it can be a good alternative for certificate based proxy signatures, used in various applications such as wireless e-commerce, mobile agents, mobile communication and distributed shared object systems, etc.     

Toward Automated Support for Transparent Interoperable Queries

Many Object-Oriented Databases (OODBs) use programming languages that predate Java, such as C++, CLOS and Smalltalk. Thus, there is a growing need for interoperating these OODBs with new applications that require Java. Unfortunately, there are few mechanisms that allow software developers to easily integrate Java applications with non-Java OODBs. Although various interoperability mechanisms have been developed over the years, these approaches have some significant drawbacks in practice. They are often difficult to use, provide little, if any, automated support, and produce software that is difficult to engineer and maintain. In this paper, we describe an interoperability approach that allows application developers to seamlessly and transparently access non-Java OODBs from Java applications. We first present JOQL, a Java-based object query language that we are developing. JOQL queries are embedded in Java applications and are used to perform queries over C++-based OODBs. We also describe an accompanying toolset that processes Java programs containing JOQL queries. The toolset produces all the necessary code allowing Java applications to access and manipulate a C++-based OODB. As a result, application developers are free to work in Java without having to concern themselves with the details of interoperating with C++. Finally, we provide some preliminary experimental data that demonstrates our approach incurs a reasonable performance overhead.     

JAVA对象持久化技术Hibernate的研究和应用

Hibernate是一个对象持久化工具,它通过其强大的O/R映射功能将Java对象同存放于关系数据库中的数据进行映射,避免了开发人员使用大量的SQL语句通过JDBC的方式对数据库进行操作,可以有效地提高开发的效率.