Java用代码建立到jdbc的连接 [英] Java establish connection to jdbc with code
问题描述
您好，我正在努力建立一个自动连接到我的jdbc数据库。当我运行程序时，它给我这个错误： java.sql.SQLNonTransientConnectionException：java.net.ConnectException：错误连接到服务器localhost在端口1527与消息连接拒绝：连接。
Hello I am struggeling to establish an automatic connection to my jdbc database. When ever I run the program it gives me this error: java.sql.SQLNonTransientConnectionException:java.net.ConnectException:Error connecting to server localhost on port 1527 with message Connection refused: connect.
当我手动连接到我的jdbc驱动程序时，程序运行正常。我想知道是否有一种方法，我可以连接到驱动程序使用代码，而不是它的manualy。
When I manually connect to my jdbc driver the program works fine. I would like to know if there is a way that I can connect to the driver using code instead of doing it mannualy.
这里是我的一些代码：
String createDB = "jdbc:derby://localhost:1527/C:/211092207/HotelBookings;create=true";
String createCustomer = "CREATE TABLE CUSTOMER ( CUSTOMERID NUMERIC(15) NOT NULL PRIMARY KEY, LASTNAME VARCHAR(20), FIRSTNAME VARCHAR(20), GENDER CHAR(1), EMAIL VARCHAR(50), CREDITRATING VARCHAR(9), NATIONALITY VARCHAR(20), DATEOFBIRTH VARCHAR(20), PHONE NUMERIC(10), CELLPHONE NUMERIC(10) )";
String createRoom = "CREATE TABLE ROOM ( ROOMNO NUMERIC(5) PRIMARY KEY, ROOMTYPE VARCHAR(9), DAILYRATE NUMERIC(20), STATUS CHAR(1))";
String createBooking = "CREATE TABLE BOOKING (BOOKINGID NUMERIC(10) NOT NULL PRIMARY KEY, ROOMNO NUMERIC(5), PROPOSEDCHECKINDATE DATE, PROPOSEDCHECKOUTDATE DATE, CHECKEDIN CHAR(1), ACTUALCHECKINDATE DATE, CHECKEDOUT CHAR(1), ACTUALCHECKOUTDATE DATE, CANCELLED CHAR(1), CANCELDATE DATE, CANCELREASON VARCHAR(100),AMOUNT NUMERIC(20), PAYDATE DATE, PAYMODE VARCHAR(15), STATUS VARCHAR(50), PAID CHAR(1), DATE DATE, CUSTOMERID NUMERIC(15))";
String refOne = "ALTER TABLE BOOKING ADD FOREIGN KEY(CUSTOMERID) REFERENCES CUSTOMER(CUSTOMERID)";
String refTwo = "ALTER TABLE BOOKING ADD FOREIGN KEY(BOOKINGID) REFERENCES BOOKING(BOOKINGID)";
Date one = new Date(20/9/2014);
Date two = new Date(10/10/1010);
Date three = new Date(16/9/2014);
Booking book = new Booking();
book.SetBookingID("9879974564");
book.SetRoomNumber("001");
book.SetProposedCheckInDate(one);
book.SetProposedCheckOutDate(one);
book.SetCheckedIn('F');
book.SetActualCheckInDate(one);
book.SetActualCheckOutDate(one);
book.setCancelled('F');
book.SetCancelDate(two);
book.SetCancelReason("");
book.SetAmount(10.20);
book.SetPayDate(one);
book.SetPayMode("Bank Deposit");
book.SetStatus("Done");
book.SetPaid('T');
book.SetDate(three);
book.SetCustomerID("9112315190086");
String insertStatement = ("INSERT INTO ROOM(ROOMNO, ROOMTYPE, DAILYRATE, STATUS) VALUES (001, 'Single', 120.00, 'A')");
String insertStatementTwo = ("INSERT INTO ROOM(ROOMNO, ROOMTYPE, DAILYRATE, STATUS) VALUES (002, 'Single', 120.00, 'A')");
String insertStatementThree = ("INSERT INTO ROOM(ROOMNO, ROOMTYPE, DAILYRATE, STATUS) VALUES (003, 'Double', 230.00, 'A')");
String insertStatementFour = ("INSERT INTO CUSTOMER(CUSTOMERID, LASTNAME, FIRSTNAME, GENDER, EMAIL, CREDITRATING, NATIONALITY, DATEOFBIRTH, PHONE, CELLPHONE) " +
"VALUES (9112415190086, 'Nel', 'Piet', 'M', 'pietnel@hotmail.com', 'Good', 'America', '31/12/2014', 0721360363, 0721589859)");
String insertStatementFive = ("INSERT INTO CUSTOMER(CUSTOMERID, LASTNAME, FIRSTNAME, GENDER, EMAIL, CREDITRATING, NATIONALITY, DATEOFBIRTH, PHONE, CELLPHONE) " +
"VALUES (9112315190086, 'van Tonder', 'Hannes', 'M', 'hannesvantonder@gmail.com', 'Good', 'South Africa', '31/12/2014', 0711360193, 0791589789)");
String insertStatementSix = ("INSERT INTO CUSTOMER(CUSTOMERID, LASTNAME, FIRSTNAME, GENDER, EMAIL, CREDITRATING, NATIONALITY, DATEOFBIRTH, PHONE, CELLPHONE) " +
"VALUES (9115987489968, 'le Roux', 'Paul', 'M', 'paul@gmail.com', 'Good', 'South Africa', '31/12/2014', 0721361193, 0821589789)");
try
{
Connection conn = DriverManager.getConnection(createDB);
Statement stmt = conn.createStatement();
}
catch(Exception ex)
{
}
conn.close();
我怀疑maby我必须在我的try块中添加另一个语句。
当我调试我的程序的问题在于这个语句：
I suspect that maby I would have to add another statement in my try block. When I debug my program the problem lies at this statement:
Connection conn = DriverManager.getConnection(createDB);
当程序执行该语句时，它会进入catch并抛出错误信息。
when the program should execute that statement it goes to the catch and throw the error message.
推荐答案
您应该遵循JDBC中的7个步骤，
You should follow 7 steps in JDBC,
1）
2）定义连接网址
3）建立连接
4）创建一个语句对象
4)Create a Statement Object
5）执行查询
结果
7）关闭连接
你没有在任何地方加载类。
对于derby数据库，我的猜测是
you are not loading the class anywhere. For derby database my guess is
Class.forName("org.apache.derby.jdbc.ClientDriver");
此外，您刚刚创建了语句，您需要编写所需的查询，然后执行它。记得关闭。
Moreover you have just created the statement, you need to write your required query and then execute it too. remember to close.
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