Connection with oracle in java application

问题:

I have downloaded oracle express 11g edition and installed that.Now i want to connect it from java application. Here is my Connection code :-

Class.forName("oracle.jdbc.driver.OracleDriver").newInstance();
Connection conn = DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:example", "example","password123");

But when i am trying to connect it, it showing me following exception.

java.sql.SQLException: Listener refused the connection with the following error:  
ORA-12505, TNS:listener does not currently know of SID given in connect descriptor

at oracle.jdbc.driver.T4CConnection.logon(T4CConnection.java:419)
at oracle.jdbc.driver.PhysicalConnection.<init>(PhysicalConnection.java:536)
at oracle.jdbc.driver.T4CConnection.<init>(T4CConnection.java:228)
at oracle.jdbc.driver.T4CDriverExtension.getConnection(T4CDriverExtension.java:32)
at oracle.jdbc.driver.OracleDriver.connect(OracleDriver.java:521)
at java.sql.DriverManager.getConnection(DriverManager.java:582)
at java.sql.DriverManager.getConnection(DriverManager.java:185)
at javaapplication3.JavaApplication3.main(JavaApplication3.java:40)

But when i am trying to connect with "xe" database then it is connected.

Class.forName("oracle.jdbc.driver.OracleDriver").newInstance();   
Connection conn = DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:xe", "example","password123");

I dont know why this is happening?. Please give me some reference or hint.

回答1:

I think, you are misunderstanding between database schema and database type. In Oracle, XE means Express Edition of oracle database. ORCL means Oracle Corp.

In mysql

DriverManager.getConnection("jdbc:mysql://localhost:3306/test", "example","password123");

`test` is a database schema.

In Oracle XE

DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:xe", "example","password123");
DriverManager.getConnection("jdbc:oracle:thin:scott/tiger@myhost:1521:orcl","example", "password123");

`example`: database schema name and DB user name are the same.

回答2:

The connection URLs for Oracle are in the format:

jdbc:oracle:thin:@HOST:PORT:SID

The SID is a site identifier. In a full oracle install you could have multiple SIDs, but for Oracle Express this will always be XE.

What you are refering to as a "database" equates to a "user" in Oracle ("example" in your code above). Tables etc... are created under that user.

回答3:

Check which instances are known to listener by executing : lsnrctl services

Check your tnsnames.ora

Check your SID parameters for typo and invalid parameters value

回答4:

In URL pattern XE and orcl are the service id's for the Oracle. For Oracle expressed edition "xe" is used and for Oracle Enterprised edition "orcl" is used..