JDBC中Statement,PreparedStatement,CallableStatement三個方法的實例

public void ListStudents() throws SQLException{
　int i, NoofColumns;
　String StNo, StFName, StLName;
　//初始化並加載JDBC-ODBC驅動程序
　Class.forName("jdbc.odbc.JdbcOdbcDriver");
　//創建連接對象
　Connection Ex1Con = DriverManager.getConnection("jdbc:odbc:StudentDB";uid="admin";pw="sa");
　//創建一個簡單的Statement對象
　Statement Ex1Stmt = Ex1Con.createStatement();
　//創建SQL串，傳送到DBMS並執行SQL語句
　ResultSet Ex1rs = Ex1Stmt.executeQuery("SELECT StudentID, FirstName, LastName FROM Students");
　//處理每一個數據行，直到不再有數據行
　System.out.println("Student Number　　 First Name　　 Last Name");
　while(Ex1rs.next()){
　//將列值保存到java變量中
　StNo = Ex1rs.getString(1);
　StFName = Ex1rs.getString(2);
　StLName = Ex1rs.getString(3);
　System.out.println(StNo, StFName, StLName);
　}
}
public void UpdateStudentName(String StFName, String StLName, String StNo) throws SQLException, ClassNotFoundException
{
　int RetValue;
　//初始化並加載JDBC-ODBC驅動程序
　Class.forName("jdbc.odbc.JdbcOdbcDriver");
　//創建連接對象
　Connection Ex1Con = DriverManager.getConnection("jdbc:odbc:StudentDB";uid="admin";pw="sa");
　//創建一個簡單的Statement對象
　Statement Ex1Stmt = Ex1Con.createStatement();
　//創建SQL串，傳送到DBMS並執行該SQL語句
　String SQLBuffer = "UPDATE Students SET FirstName = " +
　StFName + ",LastName = " + StLName +
　"WHERE StudentNumber = " + StNo;
　RetValue = Ex1Stmt.executeUpdate(SQLBuffer);
　System.out.println("Updated" + RetValue + "rows in the Database.");
}
//使用PreparedStatement改進實例
//Declare class variables
Connection Con;
PreparedStatement PrepStmt;
boolean Initialized = false;
public void InitConnection() throws SQLException, ClassNotFoundException{
　//Initialize and load the JDBC-ODBC driver.
　Class.forName("jdbc.odbc.JdbcOdbcDriver");
　//Make the connection object.
　Con = DriverManager.getConnection("jdbc:odbc:StudentDB";uid="admin";pw="sa");
　//Create a prepared Statement object.
　PrepStmt = Con.prepareStatement("SELECT ClassName, Location, DaysAndTimes FROM Classes WHERE ClassName = ?");
　Initialized = true;
}
public void ListOneClass(String ListClassName) throws SQLException, ClassNotFoundException{
　int i, NoOfColumns;
　String ClassName, ClassLocation, ClassSchedule;
　if(!Initialized){
　InitConnection();
　}

　//Set the SQL parameter to the one passed into this method
　PrepStmt.setString(1, ListClassName);
　ResultSet Ex1rs = PrepStmt.executeQuery();
　//Process each row until there are no more rows and display the results on the console.
　System.out.println("Class Location Schedule");
　while(Ex1rs.next()){
　ClassName = Ex1rs.getString(1);
　ClassLocation = Ex1rs.getString(2);
　ClassSchedule = Ex1rs.getString(3);
　System.out.println(ClassName,ClassLocation,ClassSchedule);
　}
}
//使用CallableStatement顯示成績
//預先定義好的存儲過程的調用形式為：studentGrade = getStudentGrade(StudentID, ClassID)
public void DisplayGrade(String StudentID, String ClassID) throws SQLException
{
　int Grade;
　//Initialize and load the JDBC-ODBC dirver.
　Class.forName("jdbc.odbc.JdbcOdbcDriver");
　//Make the connection object;
　Connection Con = DriverManager.getConnection("jdbc:odbc:studentDB";uid="admin";pw="sa");
　//Create a Callable Statement object;
　CallableStatement CStmt = Con.prepareCall({? = call getStudentGrade[?,?]});

　//Now tie the placeholders with actual parameters.
　//Register the return value from the stored procedure
　//as an integer type so that the driver knows how to handle it.
　//Note the type is defined in the java.sql.Types.
　CStmt.registerOutParameter(1,java.sql.Types.INTEGER);

　//Set the In parameters (which are inherited from the PreparedStatement class)
　CStmt.setString(1,StudentID);
　CStmt.setString(2,ClassID);

　//Now we are ready to call the stored procedure

　int RetVal = CStmt.excuteUpdate();

　//Get the OUT Parameter from the registered parameter
　//Note that we get the result from the CallableStatement object
　Grade = CStmt.getInt(1);

　//And display the results on the console;
　System.out.println("The Grade is:" + Grade);
}