软硬件系统编程PPT (31).pdf

Computer Network01Lecture 32 Internet applicationFile TransferFTP：File Transfer Protocol Two meanings:File transfer protocol File transfer function,file transfer service,file transfer program Upload:Transfer files from the local to the server Download:Transfer files from the server to the localFTP server:provide a hardware and software system Two login methods:real name login,anonymous login Real-name login:registration is required,user name and login password are required for access Anonymous login:No registration required,user name Anonymous,arbitrary password Two access methodsFTP client software：FlashFXP、CuteFTP、FileZilla,etc.EmailE-mail is one of the most typical services on the InternetThree components of the email system:user agent,email protocol and mail server.User Agent:Edit,send,receive,read,and manage e-mail.Email protocol Send mail to the other partys mail server SMTP（Simple Mail Transfer Protocol）Retrieve mail from mail server POP3（Post Office Protocol v3）IMAP4（Internet MessageAccess Protocol v4）Mail transmission based on the transport layer TCPprotocol Mail Server:Receive and forward emails,and report the sending status of emails to senders.World Wide Web What is World Wide Web？The World Wide Web is an Internet-based hypertext information system Three important components of the World Wide Web Browser Web Server Hypertext Transfer Protocol万维网6ISPRouterWeb serverBrowser userHyperlinkLogical connectionPhysical connectionWWWInternetWanInternet userSome related conceptsBrowser The browser is the most frequently used Web client program.It canobtain the web page from the web server through the HTTP protocoland display its content,and allow users to interact with the web page.Common browsers include IE,Firefox,Chrome,etc.Web Server It is a hardware and software system that stores Web pages andprovides Web browsing services to browsers.Common web server platforms areApache,IIS,WebSphere,IIS,etc.Hypertext Transfer Protocol It is a communication protocol for transferring web pages between aweb server and a browser.based on TCP,default port number 80Some related conceptsUniversal Resource Locator，URL Used to describe the location of resources on the Internet and the method of accessing resources.The general format is:HTTP：/：/among them Host:Web server domain name or IP address Port:HTTP port number,default is 80,can be omitted Path:The storage path of the webpage file,this item can be omitted on the homepage of a websiteWeb page Hypertext documents written in HTML language;Use tags to identify hypertext content and mark hyperlink information;It is a text file,and the extension is usually htm or html.http:/:80/index.htmlHost and Port PathSome related conceptsHyperlink Used to describe the connection relationship from a web page to other webpages or resources.Hyperlink contains two parts:start and end Start:Explain where to create a hyperlink on the page.It can be a piece of text or a picture.If it is text,these texts aregenerally displayed in underlined blue fonts.When the mouse movesto the starting point,the shape of the mouse changes from an arrowto a hand.Clicking on the starting point will activate this link.End:Description of the web page or resource to be opened after clickingthe start point.The location of the end point can be on another website,on the samewebsite,or on the same web page.Some related conceptsWebsite A collection of related web pages with a specific theme is called a web site.The website is built on a web server.The first page you see when you enter the Web site is called the homepage.The website is stored in the publishing directory of the web serverHypertext Markup Language The standard language for making web pages,using HTML can organize various resources in a web page.HTML defines a lot of tags(tag),the main purpose of tags:Type hyperlinkHow the World Wide Web worksInternetWeb ServerWeb BrowserTCP connectionTCP port 80HTTPRequestHTTPResponseHTTPResponseHTTPResponseHTTPResponseHTTPRequestHTTPRequestHTTPRequestHTTPRequestHTTPResponseWeb pages storedin the Web serverThanks