Java Instance Learning--Enterprise Invoicing Management System (3)

Java Instance Learning--Enterprise Invoicing Management System (3)

(This example is the book instance, I am recording is my study process)

Start Date: February 12

Completion time: Not completed

2 Month Day-public class (Item public class, data model public class, Dao public Class), database operations

Before more than 160 lines of code, I was surprised, this saw more than 640 lines of code, although included in the comments, but enough to surprise me! Just one class, so much code, this one system done down, there are 30,000 lines of code is not surprising! Thank oneself has been in progress, although slow, but the foundation is to be solid geoscience good! After importing the instance file, you need to download a JDBC driver when you log in, and take the opportunity to tutorial the database Operation section.

2 Month Day-Connect to database

Today's learning time is really used in the connection database, see how I went through 9,981 difficult to finally connect to the database:

1 , please put SQL2000 the JDBC driver copied to Lib folder .

Resolution process: Baidu search Jtds, download the driver file on a website, unzip the Jtds.jar file into the Lib folder.

2 , user sa Login failed.

Resolution process: I installed the SQL, forgot the SA account settings password, the instance is connected with the SA account, and the password is empty, I have been in Baidu how to change the sa account password to empty, in fact, as long as the setting of the password where the black point removed, save on it, I see the password again when the column there is a solid black circle, thinking that they did not set up, fell into the cycle of death, has been Baidu, has been changed, has been seen, there are black dots. I also changed the original SA account name, a new SA account, password that column or there is a solid black circle, ( I always thought the password is empty, the password that column is blank, this is let me get stuck in the cause of jumping out ), and later after a long time, with the SA account connection, no password can also login, This only realizes the password is empty, the password that column still will have the solid black circle! ( the mind is too cured )

3.sa The account cannot be attached to the database.

Resolution process: Although the SA account setup is successful, you can log on, but you cannot attach the database when you attach it to the SA account!! It's really difficult to find a mother! After Baidu know is SA account does not set administrator rights. According to the operation of Baidu, SA account can be attached to the database.

4. The database you want to attach is inaccessible.

Resolution process: The SA account can be attached to the database, I can open happily to the back of the study, I think, the new level immediately appeared in front: unable to access the database I need!!! Oh, my God! Is this going to test my willpower? Java problem by my abruptly to become a database problem, continue to Baidu, is the database file permissions problem! At the beginning of the folder to change permissions, or not, read several articles, really want to crash state, then the sky is getting dark, I stopped, began to do housework. Just now, I put the folder in the two files a change of authority, finally, finally, finally succeeded!!! Fortunately did not give up!!

Today's problems are non-programming problems, on the way to ask the teacher, ask a group of friends, but did not wait for a timely and effective response, are relying on Baidu search to solve the problem, so, after the study does not understand the problem, priority Baidu, do not understand to find classmates, find teachers!

It's fun to solve problems, but efficiency needs to be improved!

Tomorrow we will pack things, the day after tomorrow to go to school! Back to school continue to iron ~ (haha, the teacher said "iron")

English card:

API: Application Interface

SQL: Structured Query Language

Build paths: Build Path

Configuration build Path: Configure build paths

Java Instance Learning--Enterprise Invoicing Management System (3)