jdbc的簡單使用

1.加載驅動(mysql的驅動是com.mysql.jdbc.Driver,SqlServer的驅動是 com.microsoft.sqlserver.jdbc.SQLServerDriver)mysql

2.加載數據庫的鏈接(url, username,password)sql

3.編寫sql語句(String sql="select * from grade  where gradeName = ?";)數據庫

4.遍歷查詢結果 【while (resultSet.next()) {
   System.out.println(resultSet.getInt("gradeId") + "  " + resultSet.getString("gradeName"));
  }】sqlserver

5.關閉資源(從後向前關閉資源 )url

 

public class Test {
public static void main(String[] args) {
 Connection connection = null;
 PreparedStatement preparedStatement = null;
 ResultSet resultSet = null;
 try {
  // 加載數據庫驅動
  Class.forName("com.mysql.jdbc.Driver");
  // 經過驅動管理類獲取數據庫連接
  connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/myschool?characterEncoding=utf-8", "root", "root");
  // 定義sql語句 ?表示佔位符
  String sql = "select * from grade  where gradeName = ?";
  // 獲取預處理statement
  preparedStatement = connection.prepareStatement(sql);
  // 設置參數,第一個參數爲sql語句中參數的序號(從1開始),第二個參數爲設置的參數值
  preparedStatement.setString(1, "二年級");
  // 向數據庫發出sql執行查詢,查詢出結果集
  resultSet = preparedStatement.executeQuery();
  // 遍歷查詢結果集
  while (resultSet.next()) {
   System.out.println(resultSet.getInt("gradeId") + "  " + resultSet.getString("gradeName"));
  }
 } catch (Exception e) {
  e.printStackTrace();
 } finally {
  // 釋放資源
  if (resultSet != null) {
   try {
    resultSet.close();
   } catch (SQLException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
   }
  }
  if (preparedStatement != null) {
   try {
    preparedStatement.close();
   } catch (SQLException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
   }
  }
  if (connection != null) {
   try {
    connection.close();
   } catch (SQLException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
   }
  }
 }
}
}server

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