连接数据库 增加 删除 查询 修改 (swing中)

1. 插入
//插入语句连接数据库(按钮)
 public static Connection fetchconnection()
 {
  try{
         Class.forName("oracle.jdbc.driver.OracleDriver");
      String url ="jdbc:oracle:thin:@192.168.119.108:1521:orclcn";
   String user = "zenggan";
   String pwd = "zeng";
      return DriverManager.getConnection(url, user, pwd);
  }
  catch(Exception e)
  {
   e.printStackTrace();
   return null;
  }
 }

 
 private void addCourseButtonActionPerformed(ActionEvent evt) throws SQLException {
  /**
   * 插入语句
   */
  //---------------------------------
  Statement statement = null;
  Connection connection =null;
  //ResultSet resultSet = null;
  try{
   connection = fetchconnection();
   //System.out.println(connection);
   statement = connection.createStatement();
   
   String sql = "insert into subject(sub_id,sub_name,credit) values('"+this.sub_idTextField.getText()+"','"+this.sub_nameTextField.getText()+"','"+this.creditTextField.getText()+"')";
      statement.executeUpdate(sql);
     
  }
  catch(Exception e)
  {
      e.printStackTrace();
  }
  finally{
   //resultSet.close();
   statement.close();
   connection.close();
  }

2. 查询
Statement statement = null;
  Connection connection =null;
  ResultSet resultSet = null;
  try{
   connection = fetchconnection();
   //System.out.println(connection);
   statement = connection.createStatement();
   
  /* String sql = "insert into class values(120,'zeng')";
   int i = statement.executeUpdate(sql);
    System.out.println(i);  */
   
   String sql = "select * from class";
   resultSet = statement.executeQuery(sql);
   while(resultSet.next())
   {
     System.out.println("id: "+resultSet.getLong("id")+"| name: "+resultSet.getString("psd"));
   }   
  }
  catch(Exception e)
  {
      e.printStackTrace();
  }
  finally{
   resultSet.close();
   statement.close();
   connection.close();
  }

 }
 public static Connection fetchconnection()
 {
  try{
         Class.forName("oracle.jdbc.driver.OracleDriver");
      String url ="jdbc:oracle:thin:@192.168.119.108:1521:orclcn";
   String user = "zenggan";
   String pwd = "zeng";
      return DriverManager.getConnection(url, user, pwd);
  }
  catch(Exception e)
  {
   e.printStackTrace();
   return null;
  }
 }

3. 查询ID>5的数据库里面的信息
 public static void main(String[] args) throws Exception {
  
  PreparedStatement statement = null;
  Connection connection =null;
  ResultSet resultSet = null;
  try{
   connection = fetchconnection();
   
   String sql = "select * from class where id > ?";
   statement = connection.prepareStatement(sql); 
   statement.setLong(1, 5);//此处是最大区别
   resultSet = statement.executeQuery();
   while(resultSet.next())
   {
     System.out.println("id: "+resultSet.getLong("id")+"| name: "+resultSet.getString("psd"));
   }   
  }
  catch(Exception e)
  {
      e.printStackTrace();
  }
  finally{
   resultSet.close();
   statement.close();
   connection.close();
  }

 }
 public static Connection fetchconnection()
 {
  try{
         Class.forName("oracle.jdbc.driver.OracleDriver");
      String url ="jdbc:oracle:thin:@192.168.119.108:1521:orclcn";
   String user = "zenggan";
   String pwd = "zeng";
      return DriverManager.getConnection(url, user, pwd);
  }
  catch(Exception e)
  {
   e.printStackTrace();
   return null;
  }
 }
}

4.  插入多条语句时代码
public static void main(String[] args) throws Exception {
  
  Statement statement = null;
  Connection connection =null;
  ResultSet resultSet = null;
  try{
   connection = fetchconnection();
   connection.setAutoCommit(false);    //设置为手动提交
   String sql = "insert into class values(119,'火警')";
   statement = connection.createStatement(); 
   int updateline = statement.executeUpdate(sql); 
   sql = "insert into class values(110,'匪警')";
   statement.executeUpdate(sql);
   sql = "insert into class values(111,'不知111')";
   statement.executeUpdate(sql);
   connection.commit();
   
   sql = "insert into class values(112,'不知112')";
   statement.executeUpdate(sql);
   sql = "insert into class values(114,'据说咨询XX')";
   statement.executeUpdate(sql);
   sql = "insert into class values(115,'不知115')";
   statement.executeUpdate(sql);
   connection.rollback();
  }
  catch(Exception e)
  {
      e.printStackTrace();
  }
  finally{
   //resultSet.close();
   statement.close();
   connection.close();
  }

 }
 public static Connection fetchconnection()
 {
  try{
         Class.forName("oracle.jdbc.driver.OracleDriver");
      String url ="jdbc:oracle:thin:@192.168.119.108:1521:orclcn";
   String user = "zenggan";
   String pwd = "zeng";
      return DriverManager.getConnection(url, user, pwd);
  }
  catch(Exception e)
  {
   e.printStackTrace();
   return null;
  }
 }