電大開放本科論文：計算機(jī)網(wǎng)絡(luò)畢業(yè)論文-

1、電大開放本科論文：計算機(jī)網(wǎng)絡(luò)畢業(yè)論文-computer network graduation thesiscomputer network graduation thesisuniversity of capital normal university network education college graduate thesis (design)paper topicsthe name of the school is the school of management of the schoolj2me based communications book programmingli 4

2、(education college of shaanxi normal university, xi j an, 7100abstract: personalized intelligent information products such as mobile phones, set-top boxes, smart cards and handheld computers have become more and more common. because of the characteristics of these devices themselves, developers are

3、faced with platform differences, difficult to migrate, and the emergence of j2me can solve these problems effectively. j2me is a kind of the java language model applied to embedded system software development, and has many advantages in java technology, very suitable for the development of mobile de

4、vice applications paper first introduces the j2me system structure and its related technology, then introduces how to use j2me development with add, delete, modify, query the four basic functions of mobile communication book management system, and gives the j2me application development process and b

5、asic programming technology. through the address book management system development process shows that using j2me mobile application development has the characteristics of simple programming, portability strong, so the application of j2me technology will be more and more widely. keywords: midp j2me

6、rms mobile phone directory1 introductionthe 1. 1 wireless network overview now, with the combination of internet and mobile communication technology, wireless network technology is developing rapidly. what is a wireless network? the so-called wireless network, is to use radio waves as information tr

7、ansmission medium consisting of a wireless local area network (lan), use very similar with wired network, the biggest difference is that the different transmission medium, it uses radio technology replacing cables cable networks in some occasions should be restricted the wiring, wiring, relocate lar

8、ge quantities, easy to damage, the sections in the net point is mobile, networking demand for is expanding rapidly formed a severe bottleneck blocking the wireless network wlan is designed to solve the problem of wired networks devices commonly used for wireless networks include portable computers,

9、desktop computers, handheld computers, personal digital devices (pdas), mobile phones, and so on. wireless technology is widely used, for example, mobile phone users can use mobile phone access to connect to the internet at home, users can connect to desktop devices to send files synchronously. thes

10、e devices make a big difference in our lives and play anincreasingly important role at the same time, because of the rapid development of internet makes people more and more depend on the available information on the inter net, people no longer content to mobile phone, pda and other equipment at the

11、 factory with a fixed limited functionality, but hope, like computer, can be convenient to mobile phone, pda and other small consumer applications and embedded devices installed various needs, rather than to buy new equipment1.2 development of wireless application difficult because of the characteri

12、stic of the small consumer and embedded devices, such as variety, calculation ability is limited, the particularity of limited memory, output, input devices, wireless application development with the desktop or enterprise computing application development is very different 1 for desktop and enterpri

13、se computing applications, the development platform is typically the same as the deployment environment, which can be connected to the application by high-speed network3establish a connection. but things just a wireless device, by contrast, in a long time in the past, wireless devices are in place r

14、ichard poor performance, memory and a graphical user interface with limited resources, the condition of network connection speed s1ow and unreliable currently, developers face three main problems with application development for wireless devices:(applicability of development tools (1)2) the actual w

15、ireless test environment ( 3) reliable and scalable service support part of the reason of the problem is the lack of consistency for wireless equipment application development environment, as well as the lack of appropriate wireless application infrastructure although there are many difficulties in

16、the development of wireless applications, the development is still obtained the fast development of wireless applications, and with the release of j2me development platform, make a lot of problems wel1.the 1. 3 wireless application development platform introduction brew? binary runtime environment f

17、or wireless, wireless binary runtime environment, was launched in 2001, qualcomm company "wireless internet launch platfornt based on cdma network on the basic platform of value-added business development 2 for java, brew is a more low-level technology. the brew provides a highly efficient, low

18、 cost, extensible, and familiar with application execution environment (aee), focus on development can be seamlessly into any actual handheld device applications. manufacturers and developers can extensions to the running environment, provide various application need additional module performance, s

19、uch as "wireless internet launch platform/，contained in the multimedia, multiple connection methods, location services, user interface, and network function suite brew provides a functional environment that, like the operating system on a pc, can be downloaded by a service provider for a specif

20、ied type of application or game at the same time, through the brew interface work, the supplier can provide complete information, business and entertainment functions. the platform while the function is a lot but it is not very mature, and mainly is to use c language to develop, can only work in the

21、 cdma network, according to statistics, the global 34 operators use the java, and only 8 operators use the brew, application scope is relatively smal1. the currently widely used development platform for mobile is the j2me (java 2 micro edition), a java for embedded systems kvm j2me technology consis

22、ts of a virtual machine virtual machine (k) and a set of apis, is suitable for this set of apis for consumption and cut-outs of embedded electronic devices running environment 2 the kvm virtual machine itself only needs 40-80kb of memory, 20-40kb dynamic memory (heap), and can run on 16 25mhz proces

23、sors for j2me mobile interconnection, introduces a new model that allows mobile phones can be downloaded from the internet applications, and on the phone and made offline run the programs executable environment as a java technology small devices such as mobile phone version, it is on screen, power a

24、nd memory resources such as limited mobile device is optimized and the definition, in order to solve the contradictions of wireless devices diversification, sun in accordance with all sorts of equipment resource features the j2me technology architecture is divided into the java virtual machine (jvm)

25、, configuration (configuration) and profiling (profile) of three layers, and then further subdivided, this makes the j2me able to work under the limit to each type of equipment, and to provide the minimum functional java language the brew and j2me is one of the major wireless application development

26、 platform, in addition to these two have e, symbian, windows mobile, rfgen wireless application development platform in this not introduced.1.4 wireless application field and development prospect of wireless technology plays more and more important role in our life, and brought great convenience to

27、our life, the most widely used, is closely related to our most mobile applications it's hard to find a mobile phone does not support java, because mobile phones now not only as the tool of calls, and have come to the tool development, entertainment and even business office tools wireless network

28、 and the development of wireless devices to wireless devices, software opened up a broad prospect, maybe will soon come to people in business trip or travel to network game, can use mobile phone or via mobi1e phone to access and enjoy the internet servicewith the combination of internet and mobile c

29、ommunication technology, wireless internet technology is developing rapidly. wireless internet technology has come up with a range of wireless access standards following wap technology. 802.as 802. 11 a/b/g, 802.16, 8bluetooth, infrared, gprs, cdma ix, 3g, etc. because of the variety of mobi 1 e acc

30、ess devices, the hardware, os, application platform and application software of wireless terminal devices are different thus, the technology for portability, hyperplatform differences, and j2me was born. this project is one of the sub-tasks of the key scientific research project of shaanxi normal un

31、iversity (wireless network adaptive security architecture) in this paper, on the basis of introduction to java, detailed discusses the system structure of j2me architecture, through the design and development of the communication book management system based on j2me, tells the j2me application devel

32、opment related programming techniquesintroduction to the java language2. 1 the java language with the rise of the internet and www and continuous development, need to develop a number of large software system, how to simplify the development, design and maintenance of these big type system, the syst

33、em has the flexibility, portability and interoperability, become software development must consider the question. the design language of java, which was officially launched by sun microsystems in may 1995, was the answer java language had a very good portability, security, online, and on the difficu

34、lty of programming than c/c + + language is simple, is currently in the design of software is extremely robust programming languages, especially suitable for the development of network application. one of the biggest benefits of java for developers is "'compile once and run，/ 3 why is the j

35、ava language so popular? because it has the following features, 4:(1) simplicity: java is a streamlined system that works well without a strong hardware environment java style and grammar is similar to c + +, in a sense, the java language is a variant of c and c + + language, therefore, c + + progra

36、mmers can quickly master java programming technology. java abandoned the c + + easy triggering procedure in the wrong places, such as multiple inheritance, operator overloading, pointers and memory management, etc，the java language has support multithreading, automatic garbage collection and use the

37、 features such as reference java provides a rich library of libraries that allows users to quickly master java(2) object-oriented (object oriented) : object-oriented is arguably the most important feature of java the java language is designed5fully object-oriented, it does not support process-orient

38、ed programming techniques such as c language all java programs and applets are objects, and java supports both static and dynamic style code inheritance and reuse(distributed (distributed) : java includes a sublibrary that supports http and ftp based on tcp/ip protocols because of this, the java app

39、lication can open and access objects on the network with the url, just as simple as accessing local files the distribution of java provides the technical means for implementing dynamic content in a distributed environment, especially in the internet(robustness: java is a strongly typed language that

40、 has a lot of type checking to compile and run. type checking helps to examine many of the errors that occurred early in development java，s own manipulation of memory reduces the possibility of memory errors java arrays are not implemented with pointers, thereby avoiding the possibility of an array

41、crossing. java avoids many errors caused by memory management by the automatic garbage collector java also avoids many errors by not using pointers in the program to access memory units(neutral (5) structure architecture neutral) : as a kind of network language, the java compiler to compile the java

42、 source code into a has nothing to do with the architecture in the middle of the file format only a machine with a java running system can execute this medium code this enables the same version of the application to run on different platforms(6) security: as a network language, security is very impo

43、rtant the security of java can be guaranteed in two ways on the one hand, in the java language, c + + functions such as pointer and free memory are deleted, avoiding non-normal memory operations. on the other hand, when java is used to create a browser, the language functionality is combined with th

44、e functionality provided by the browser itself to make it more secure the java language is tested many times before it is executed on your machine it passes code validation, checks the format of the code segment, detects the pointer operation, and tries to change the type of an object in addition, j

45、ava has multiple levels of interlock protection, which effectively prevents the virus from invading and damaging behavior(7) portable (portable) : java has nothing to do with the architecture characteristics make java applications can be equipped with java interpreter and running environment of runn

46、ing on any computer system, it become a basis for the java application software to facilitate transplantation. but that is not enough if the basic data type design depends on the implementation, it will also cause a lot of inconvenience to the migration of the program. java by defining a platform-in

47、dependent basic data types and their operations, the number of java according to be able to be consistent in any hardware platform, it also embodies the portability of java language and java compiler itself is written in the java language, compiled on the basis of the posix convenient transplantation of java computing systems limit system, written in ansic language in the java language specification, does not have any ''may be related to the implementation of content,