Java语言程序设计10E LiangPPT习题案例35slide.ppt

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1、1Chapter35AdvancedJavaDatabaseProgramming2ObjectivesTocreateauniversalSQLclientforaccessinglocalorremotedatabase(§35.2).ToexecuteSQLstatementsinabatchmode(§35.3).Toprocessupdatableandscrollableresultsets(§35.4).TosimplifyJavadatabaseprogrammingusingRowSet(§35.5).Tostoreand

2、retrieveimagesinJDBC(§35.6).3Example:CreatinganInteractiveSQLClientConnecttoanyJDBCdatasource.SQLClientRunEnteringandexecutingSQLcommandsinteractivelyTheexecutionresultisdisplayedfortheSELECTqueries,andtheexecutionstatusisdisplayedforthenon-SELECTcommands.4BatchUpdatesToi

3、mproveperformance,JDBC2introducedthebatchupdateforprocessingnonselectSQLcommands.AbatchupdateconsistsofasequenceofnonselectSQLcommands.Thesecommandsarecollectedinabatchandsubmittedtothedatabasealltogether.Statementstatement=conn.createStatement();//AddSQLcommandstothebatch

4、statement.addBatch("createtableT(C1integer,C2varchar(15))");statement.addBatch("insertintoTvalues(100,'Smith')");statement.addBatch("insertintoTvalues(200,'Jones')");//Executethebatchintcount[]=statement.executeBatch();TheexecuteBatch()methodreturnsanarrayofcounts,eachofwh

5、ichcountsthenumberoftherowsaffectedbytheSQLcommand.Thefirstcountreturns0becauseitisaDDLcommand.Therestofthecommandsreturn1becauseonlyonerowisaffected.5Example:CopyingTextFilestoTableWriteaprogramthatgetsdatafromatextfileandcopiesthedatatoatable.Thetextfileconsistsoftheline

6、s,eachofwhichcorrespondstoarowinthetable.Thefieldsinarowareseparatedbycommas.Thestringvaluesinarowareenclosedinsinglequotes.YoucanviewthetextfilebyclickingtheViewFilebuttonandcopythetexttothetablebyclickingtheCopybutton.Thetablemustalreadybedefinedinthedatabase.CopyFileToT

7、ableRun6ScrollableandUpdateableResultSetTheresultsetsusedintheprecedingexamplesarereadsequentially.Aresultsetmaintainsacursorpointingtoitscurrentrowofdata.Initiallythecursorispositionedbeforethefirstrow.Thenext()methodmovesthecursorforwardtothenextrow.Thisisknownassequenti

8、alforwardreading.ItistheonlywayofprocessingtherowsinaresultsetthatissupportedbyJDBC1.With