Java语言程序设计10E LiangPPT习题案例38slide.ppt

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1、1Chapter38JavaServerPage2ObjectivesTocreateasimpleJSPpage(§38.2).ToexplainhowaJSPpageisprocessed(§38.3).TouseJSPconstructstocodeJSPscript(§38.4).TousepredefinedvariablesanddirectivesinJSP(§§38.5-38.6).TouseJavaBeanscomponentsinJSP(§38.7-38.9).Todevelopdatabaseappli

2、cationsusingJSP(§38.7-38.9).ToforwardrequestsfromaJSPpagetoanother(§38.10).3ASimpleJSPCurrenttimeis<%=newjava.util.Date()%>Run4HowIsaJSPProcessed?5JSPConstructsTherearethreetypes

3、ofscriptingconstructsyoucanusetoinsertJavacodeintotheresultantservlet.Theyareexpressions,scriptlets,anddeclarations.expressionscriptletdeclarationAJSPexpressionisusedtoinsertaJavaexpressiondirectlyintotheoutput.Ithasthefollowingform:<%=Java-expression%>Theexpressio

4、nisevaluated,convertedintoastring,andsenttotheoutputstreamoftheservlet.6JSPConstructsTherearethreetypesofscriptingconstructsyoucanusetoinsertJavacodeintotheresultantservlet.Theyareexpressions,scriptlets,anddeclarations.expressionscriptletdeclarationAJSPscriptletena

5、blesyoutoinsertaJavastatementintotheservlet’sjspServicemethod,whichisinvokedbytheservicemethod.AJSPscriptlethasthefollowingform:<%Javastatement%>7JSPConstructsTherearethreetypesofscriptingconstructsyoucanusetoinsertJavacodeintotheresultantservlet.Theyareexpressions

6、,scriptlets,anddeclarations.expressionscriptletdeclarationAJSPdeclarationisfordeclaringmethodsorfieldsintotheservlet.Ithasthefollowingform:<%!Javamethodorfielddeclaration%>8JSPCommentHTMLcommentshavethefollowingform:Ifyoudon’twantthecommentappeari

7、ntheresultantHTMLfile,usethefollowingcommentinJSP:<%--JSPComment--%>9Listing38.1ComputingFactorials<%for(inti=0;i<=10;i++){%>Factorialof<%=i%>is<%=computeFactorial(i)%>
<%}%><%!privatelongcomputeFactorial(intn){i

8、f(n==0)return1;elsereturnn*computeFactorial(n-1);}%>JSPscriptletJSPexpressionJSPdeclarationRun10JSPPredefinedVariablesYoucanusevari