2023學年完整公開課版Java數(shù)據(jù)查詢

數(shù)據(jù)查詢2學習目標知識目標01能力目標能夠合理運用JDBC查詢數(shù)據(jù)02熟悉JDBC數(shù)據(jù)查詢的步驟掌握JDBC數(shù)據(jù)查詢的關(guān)鍵代碼3數(shù)據(jù)庫準備執(zhí)行數(shù)據(jù)庫命令，創(chuàng)建了一個JdbcDemo數(shù)據(jù)庫，新建了一個Admin關(guān)系表。CREATEDATABASEJdbcDemoGOUSEJdbcDemoGOCREATETABLEAdmin(IDINTPRIMARYKEY,PwdCHAR(10)NOTNULL)

INSERTINTOAdminVALUES(1001,'abc123')INSERTINTOAdminVALUES(1002,'def456')INSERTINTOAdminVALUES(1003,'xyz890')4實現(xiàn)步驟編寫代碼，新建類Test，通過JDBC技術(shù)連接數(shù)據(jù)庫的主要步驟：

1、反射加載驅(qū)動程序類Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");2、通過驅(qū)動類DriverManager獲取與數(shù)據(jù)庫的連接Connectionconn=DriverManager.getConnection(URL,USER,PWD);//參數(shù)說明URL：數(shù)據(jù)庫地址(jdbc:sqlserver://127.0.0.1:1433;DatabaseName=JdbcDemo)USER：登陸數(shù)據(jù)庫的用戶名PWD：驗證密碼

3、得到連接conn后，獲取可執(zhí)行sql語句的Statement對象Statementstmt=conn.createStatement()；5實現(xiàn)步驟4、新建sql語句,通過stmt的executeQuery(sql);執(zhí)行查詢語句，并返回得到結(jié)果集ResultSet,遍歷結(jié)果集rs，輸出Admin關(guān)系表中的記錄Stringsql=“select*fromAdmin”;ResultSetrs=stmt.exectueQuery(sql);while(rs.next()){Stringid=rs.getString("ID");Stringpwd=rs.getString("Pwd");System.out.println(id+”,”+pwd);}5、關(guān)閉數(shù)據(jù)庫連接conn.close();6關(guān)鍵代碼privatestaticfinalStringURL="jdbc:sqlserver://127.0.0.1:1433;DatabaseName=JdbcDemo";privatestaticfinalStringUSER="sa";//登陸身份privatestaticfinalStringPWD=“123456";//驗證密碼publicstaticvoidmain(String[]args){Connectionconn=null;try{

//1.反射加載驅(qū)動程序類Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");}catch(ClassNotFoundExceptione){System.out.println("未發(fā)現(xiàn)類..");

}7關(guān)鍵代碼try{

//2.通過驅(qū)動類DriverManager獲取與數(shù)據(jù)庫的連接conn=DriverManager.getConnection(URL,USER,PWD);}catch(SQLExceptione){System.out.println("無法連接數(shù)據(jù)庫..");

}try{

//3.得到連接conn后，獲取可執(zhí)行sql語句的Statement對象Statementstmt=conn.createStatement();

//4.執(zhí)行sql語句，獲取查詢結(jié)果，并輸出Stringsql="select*fromAdmin";ResultSetrs=stmt.executeQuery(sql);8關(guān)鍵代碼while(rs.next()){Stringid=rs.getString("ID");Stringpwd=rs.getString("Pwd");System.out.println(id+","+pwd);

}}catch(SQLExceptione){System.out.println("sql語句執(zhí)行出錯..");}finally{if(conn!=null){try{conn.close();//5.關(guān)閉數(shù)據(jù)庫連接}catch(SQLExcepti