Java以編程的形式連接數(shù)據(jù)庫，并實現(xiàn)多表查詢，查詢條件是三年級2班，語文成績大于80分的學生，并打出名單。代碼如下：packagePublic;importjava.sql.*;//建立類Conn,連接MySQL數(shù)據(jù)庫，數(shù)據(jù)庫多表查詢。publicclassConn{publicstaticvoidmain(String[]args){//聲明Connection對象Connectioncon;//數(shù)據(jù)庫驅(qū)動StringDRIVER="com.mysql.jdbc.Driver";//3306后面為數(shù)據(jù)庫名字測試時可以刪除Stringurl="jdbc:mysql://localhost:3306/stu_glxt";Stringusername="root";//數(shù)據(jù)庫密碼Stringpassword="123456";try{//注冊驅(qū)動Class.forName(DRIVER);//1.getConnection()方法，連接MySQL數(shù)據(jù)庫！！con=DriverManager.getCo門門ectlo門(url,username,password);if(!con.isClosed())System.out.println("SucceededconnectingtotheDatabase!");//2?創(chuàng)建statement類對象，用來執(zhí)行SQL語句??！Statementstatement=con.createStatement();//要執(zhí)行的SQL語句，查詢?nèi)昙?班語文成績大于80分的學生Stringsql="selectA.sName,score,C.cName,D.sGrade,D.sClass"+"fromtb_studentASA,tb_scoreASB,tb_courseAStb_gradeASD"+"whereA.sNo=B.sNoandB.cNo=C.cNoandA.sNo=D.sNoand"+"D.sGrade='三年級'andD.sClass=2andC.cNo=000002andB.score>=80";//3.ResultSet類，用來存放獲取的結(jié)果集！！ResultSetrs=statement.executeQuery(sql);System.out.println("");Systemout.println("執(zhí)行結(jié)果如下所示：")；}}System.out.println("");Systemout?println(“姓名"+"\t"+"分數(shù)"+"\t"+"課程名"+"\t"+"年級"+"\t"+"班級");System?out?println("");StringsName=null;Stringscore=null;StringcName=null;Stringgrade=null;Stringsclass=null;while(rs?next()){//獲取sName這列數(shù)據(jù)sName=rs?getString"sName");//獲取sNo這列數(shù)據(jù)score=rs?getString"score");cName=rs?getString"cName");grade=rs?getString"sGrade");sclass=rs?getString"sClass");//輸出結(jié)果Systemout?println(sName+"\t"+score+"\t"+cName+"\t"+grade+"\t"+sclass);}rs?close();con?close();}catch(ClassNotFoundExceptione){//數(shù)據(jù)庫驅(qū)動類異常處理Systemout?println("Sorry,can'tfindtheDriver!");e?printStackTrace();}catch(SQLExceptione){//數(shù)據(jù)庫連接失敗異常處理e?printStackTrace();catch(Exceptio