The technique development history of JSP
The Java Server Pages( JSP) is a kind of according to web of the script plait distance technique, similar carries the script language of Java in the rver of the Netscape company of rver- side JavaScript( SSJS) and the Active Server Pages( ASP) of the Microsoft.JSP compares the SSJS and ASP to have better can expand x, and it is no more exclusive than any factory or some one particular rver of Web.Though the norm of JSP is to be draw up by the Sun company of, any factory can carry out the JSP on own system.
The After Sun relea the JSP( the Java Server Pages) formally, the this kind of new Web application development technique very quickly caud the people's concern.JSP provided a special development environment for the Web application that establishes the high dynamic state.According to the Sun parlance, the JSP can adapt to include the Apache WebServer, IIS4.0 on the market at inside of 85% rver product.
怀孕肚子痛This chapter will introduce the related knowledge of JSP and Databas, and JavaBean related contents, is all certainly rougher introduction among them basic contents, say perhaps to is a Guide only, if the reader needs the more detailed information, pleasing the book of consult the homologous JSP.
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ps钢笔工具怎么抠图A. Generalize
The JSP(Java Server Pages) is from the company of Sun Microsystems initiate, the many companies the participate to the build up the together of the a kind the of dynamic the state web the page technique standard, the it have the it in the construction the of the dynamic state the web page the strong but the do not the especially of the function.JSP and the technique of ASP of the Microsoft is very alike.Both all provide the ability that mixs with a certain procedure code and is explain by the language engine to carry out the procedure code in the code of HTML.Underneath we are simple of carry on the introduction to it.
B. Source of JSP
The technique of JSP of the company of Sun, making the page of Web develop the personnel can u the HTML perhaps marking of XML to design to turn the end page with format.U the perhaps small script future life of marking of JSP becomes the dynamic state on the page contents.( the contents changes according to the claim of)
The Java Servlet is a technical foundation of JSP, and the large Web applies the development of the procedure to need the Java Servlet to match with with the JSP and then can complete, this name of
Servlet comes from the Applet, the local translation method of now is a lot of, this book in order not to misconstruction, decide the direct adoption Servlet but don't do any translation, if reader would like to, can call it as" small rvice procedure".The Servlet is similar to traditional CGI, ISAPI, NSAPI etc. Web procedure development the function of the tool in fact, at u the Java Servlet hereafter, the customer need not u again the lowly method of CGI of efficiency, also need not u only th
e ability come to born page of Web of dynamic state in the method of API that a certain fixed Web rver terrace circulate.Many rvers of Web all support the Servlet, even not support the Servlet rver of Web directly and can also pass the additional applied rver and the mold pieces to support the Servlet.Receive benefit in the characteristic of the Java cross-platform, the Servlet is also a terrace irrelevant, actually, as long as match the norm of Java Servlet, the Servlet is complete to have nothing to do with terrace and is to have nothing to do with rver of Web.Becau the Java Servlet is internal to provide the rvice by the line distance, need not start a progress to the each claims, and make u of the multi-threading mechanism can at the same time for veral claim rvice, therefore the efficiency of Java Servlet is very high.
But the Java Servlet also is not to has no weakness, similar to traditional CGI, ISAPI, the NSAPI method, the Java Servlet is to make u of to output the HTML language ntence to carry out the d
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ynamic state web page of, if develop the whole website with the Java Servlet, the integration process of the dynamic state part and the static state page is an evil-foreboding dream simply.For solving this kind of weakness of the Java Servlet, the SUN relead the JSP.
The JSP is an establishment at the model of Java rvlets on of the expression layer technique, it makes the plait write the HTML to become more simple.Be like the SSJS, it also allows you carry the static state HTML contents and rvers the script mix to put together the born dynamic state exportation.JSP the script language that the Java is the tacit approval, however, be like the ASP and can u other languages( such as JavaScript and VBScript), the norm of JSP also allows to u other languages.
C. JSP characteristics
微信号怎么更改Is a rvice according to the script language in some one language of the statures system this kind of discuss, the JSP should be e make is a kind of script language.However, be a kind of script language, the JSP emed to be too strong again, almost can u all Javas in the JSP.
Be a kind of according to text originally of, take manifestation as the central development technique, the JSP provided all advantages of the Java Servlet, and, when combine with a JavaBeans together,
providing a kind of make contents and manifestation that simple way that logic parate.Separate the contents and advantage of logical manifestations is, the personnel who renews the page external appearance need not know the code of Java, and renew the JavaBeans personnel also need not be design the web page of expert in hand, can u to take the page of JavaBeans JSP to define the template of Web, to build up a from have the alike external appearance of the website that page constitute.JavaBeans completes the data to provide, having no code of Java in the template thus, this means that the templates can be written the personnel
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by a HTML plait to support.Certainly, can also make u of the Java Servlet to control the logic of the website, adjust through the Java Servlet to u the way of the document of JSP to parate website of logic and contents.
Generally speaking, in actual engine of JSP, the page of JSP is the edit and translate type while carry out, not explain the type of.Explain the dynamic state web page development tool of the type,such as ASP, PHP3 etc., becau speed etc. reason, have already can't satisfy current the large electronic commerce needs appliedly, traditional development techniques are all at to edit and translate the executive way change, such as the ASP → ASP+;PHP3 → PHP4.
In the JSP norm book, did not request the procedure in the JSP de part( be called the Scriptlet) and must write with the Java definitely.Actually, have some engines of JSP are adoptive other script languages, such as the EMAC- Script, WebL etc., but actually this a few script languages also are to t up on the Java, edit and translate for the Servlet to carry out of.Write according to the norm of JSP, have no Scriptlet of relation with Java also is can of, however, mainly lie in the ability and JavaBeans, the Enterpri JavaBeans becau of the JSP strong function to work together, so even is the Scriptlet part not to u the Java, edit and translate of performance code also should is related with Java.
D. JSP mechanism
To comprehend the JSP how unite the technical advantage that above various speak of, come to carry out various result easily, the customer must understand the differentiation of" the module develops for the web page of the center" and" the page develops for the web page of the center" first.
The SSJS and ASPs are all in veral year agos to relea, the network of that time is still very young, no one knows to still have in addition to making all business, datas and the expression logic
enter the original web page entirely heap what better solve the method.This kind of model that take page as the center studies and gets the very fast development easily.However, along with change of time, the people know that this kind of method is unwell in t up large, the Web that can upgrade applies the procedure.The expression logic write in the script environment was lock in the page, only passing to shear to slice and glue to stick then can drive heavy u.Express the logic to usually mix together with business and the data logics, when this makes be the procedure member to try to change an external appearance that applies the procedure but do not want to break with its llied business logic, apply the procedure of maintenance be like to walk the similar difficulty on the eggshell.In fact in the business enterpri, heavy u the application of the module already through very mature, no one would like to rewrite tho logics for their applied procedure.HTML and sketch the designer handed over to the implement work of their desi
gn the Web plait the one who write, make they have to double work- Usually is the handicraft plait to write, becau have no fit tool and can carry the script and the HTML contents knot to the rver to put together.Chien but speech, apply the complexity of the procedure along with the Web to promote continuously, the development method that take page as the center limits x to become to get up obviously.
At the same time, the people always at look for the better method of build up the Web application procedure, the module spreads in customer's machine/ rver the realm.JavaBeans and ActiveX were published the company to expand to apply the procedure developer for Java and Windows to u to come to develop the complicated procedure quickly by" the fast application procedure development"( RAD) tool.The techniques make the expert in the some realm be able to write the module for the perpendicular application plait in the skill area, but the developer can go fetch the usage directly but need not control the experti of this realm.
Be a kind of take module as the central development terrace, the JSP appeared.It with the JavaBeans and Enterpri JavaBeans( EJB) module includes the model of the business and the data logic for foundation, provide a great deal of label and a script terraces to u to come to show in the HTML page from the contents of JavaBeans creation or nd a prent in return.Becau of the property that regards the module as the center of the JSP, it can drive Java and not the developer of Java us equally.Not the developer of Java can pass the JSP label( Tags) to u the JavaBeans that the deluxe developer of Java establish.The developer of Java not only can establish and u the JavaBeans, but also can u the language of Java to come to control more accurately in the JSP page according to the expression logic of the first floor JavaBeans.
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See now how JSP is handle claim of HTTP.In basic claim model, a claim directly was nd to JSP page in.The code of JSP controls to carry on hour of the logic processing and module of JavaBeans' hand over with each other, and the manifestation result in dynamic state bornly, mixing with the HTML page of the static state HTML code.The Beans can be JavaBeans or module of EJBs.Moreover, the more complicated claim model can e make from is request other JSP pages of the page call sign or Java Servlets.
The engine of JSP wants to cha the code of Java that the label of JSP, code of Java in the JSP page even all converts into the big piece together with the static state HTML contents actually.The codes piece was organized the Java Servlet that customer can not e to go to by the engine of JSP, then the Servlet edits and translate them automatically byte code of Java.Thus, the visitant that is the website requests a JSP page, under the condition of it is not knowing, an already born, the Servlet actual full general that prepared to edit and translate completes all work
春天活动s, very concealment but again and efficiently.The Servlet is to edit and translate of, so the code of JSP in the web page does not need when the every time requests that page is explain.The engine of JSP need to be edit and translate after Servlet the code end is modify only once, then this Servlet that editted and translate can be carry out.The in view of the fact JSP gine auto is born to edit and tr
anslate the Servlet also, need not procedure member begins to edit and translate the code, so the JSP can bring vivid x that function and fast developments need that you are efficiently.
Compared with the traditional CGI, the JSP has the equal advantage.First, on the speed, the traditional procedure of CGI needs to u the standard importation of the system to output the equipments to carry out the dynamic state web page born, but the JSP is direct is mutually the connection with rver.And say for the CGI, each interview needs to add to add a progress to handle, the progress build up and destroy by burning constantly and will be a not small burden for calculator of be the rver of Web.The next in order, the JSP is specialized to develop but design for the Web of, its purpo is for building up according to the Web applied procedure, included the norm and the tool of a the whole t.U the technique of JSP can combine a lot of JSP pages to become a Web plication procedure very expediently.
