@数据库手动提交+隔离级别

public class ExamJdbc8 {
public static void main(String[] args) {
// if (conn.getTransactionIsolation() != Connection.TRANSACTION_NONE) {
//        conn.setTransactionIsolation(Connection.TRANSACTION_READ_COMMITTED);
//    }

//System.out.println("=================");
  String sql1 = "update emp set sal = sal - 100 where ename = ?";

  Connection conn = null;
  //一个sql对应stmt
  PreparedStatement stmt1 = null;

  //jdbc  默认自动提交事务...
  try {
  conn = SQLHelper.getConnection();
  //事务改手动
  conn.setAutoCommit(false);
  //查询现在jdbc默认事务隔离级别

 
  //未必能支 oracle jdbc driver
  conn.setTransactionIsolation(Connection.TRANSACTION_SERIALIZABLE);
  System.out.println(conn.getTransactionIsolation());  
 
  stmt1 = conn.prepareStatement(sql1);
  stmt1.setString(1,"SCOTT");
  stmt1.executeUpdate();

  conn.commit();
  conn.setAutoCommit(true);
} catch (SQLException e) {
e.printStackTrace();
try {
conn.rollback();
} catch (SQLException e1) {
e1.printStackTrace();
}
}finally{
SQLHelper.close(null,stmt1,conn);
}


}

}