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Learn JDBC steps, advantages, and running servlets. Get practical examples, resources, and create dynamic webpages with Xintao Wu's guidance.
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Oracle Programming Instructor: Xintao Wu Xintao Wu
architecture Xintao Wu
JDBC Xintao Wu
JDBC (Java Database Connectivity ) • JDBC enables programmers to use SQL queries from within java programs to access databases. • JDBC provides transparent access to relational databases from different vendors. Xintao Wu
JDBC steps • Create the database in your dbms • Register the database as a data source • Import java.sql.* at the beginning of your java file. • Connect to a JDBC source • Connection con = DriverManager.getConnection(“jdbc:oracle:thin:@coit-ora01:1521:class”,”user”,”passwd”) • Create an SQL statement • Statement stmt = con.createStatement(); • stmt.executeUpdate("INSERT INTO sailor VALUES(22,'dustin',7,45.0)"); Xintao Wu
JDBC Step • Execute the statement • ResultSet rs = stmt.executeQuery(“Select * from …”) • Parse the result • rs.next(), rs.getFloat • ResultSetMetaData contains the information about column • Close the statement and connection • stmt.close() • con.close Xintao Wu
Useful resources • JDBC tutorial http://java.sun.com/docs/books/tutorial/jdbc/index.html • UNCC COIT http://coit-servlet01.uncc.edu:8080/support/? • Example http://www.cs.uncc.edu/~xwu/WEB-INF/classes/SampleJDBC.java Xintao Wu
Java Servlets • Web servers understand requests for pages in http and return their response in HTML format • Static html vs. dynamic html • The webpage is based on data submitted by the user • The data changes frequently (a weather-report) • Web pages uses information from a database(stock) • Maintain separate data about each client for personalization purposes(cookies). • Java servlets are programs that extend the functionality of a web server and useful for building dynamic web pages on the fly. Xintao Wu
Java Servlet Advantage • Works as a lightweight thread directly with the JVM rather than create a new process • Load once to memory and used by all threads • Share data among each other Xintao Wu
How to run servlets • Your machine, Java servlet development kit(JSDK) • COIT • consult the webpage http://coit-servlet01.uncc.edu:8080/support/Examples.html • Consult TA Xintao Wu
Examples • HelloWorld • http://coit-servlet01.uncc.edu:8080/xwu/servlet/HelloWorld • http://www.cs.uncc.edu/~xwu/WEB-INF/classes/HelloWorld.java • More examples • http://coit-servlet01.uncc.edu:8080/support/Examples.html • DBServlet • http://coit-servlet01.uncc.edu:8080/xwu/DBServlet.html • http://www.cs.uncc.edu/~xwu/WEB-INF/classes/DBServlet.java Xintao Wu
JDBC and Servlet • Summary: • 1. Download PUTTY and WinSCP • 2. Download HelloWorld, SampleJDBC and DBServlet source code • 3. Modify them and upload to your own space • 4. Compile and run it • http://coit-servlet01.uncc.edu:8080/xwu/ojdbc14.jar • export CLASSPATH=$CLASSPATH:~/public_html/WEB-INF/classes/ojdbc14.jar Xintao Wu
Some links • http://coit-servlet01.uncc.edu:8080/support • http://www.chiark.greenend.org.uk/~sgtatham/putty Xintao Wu
Some files you need • http://www.cs.uncc.edu/~xwu/5160/ojdbc14.jar • http://www.cs.uncc.edu/~xwu/5160/servlet-api.jar • http://www.cs.uncc.edu/~xwu/5160/.bashrc • Visit the following to set up JDBC and servlet enviorment Note: We don’t need bashrc file for the new system Xintao Wu
Summary • 3-tire architecture • APIs such as JDBC and ODBC introduce a layer of abstraction between application and DBMS • Choose your language from JSP, Servlet, ASP, VC++, VB. Xintao Wu