Prentice Hall and Sun Microsystems. Personal use only; do not redistribute.

522

Appendix A

Servlet and JSP Quick Reference

Servlet Life Cycle

  public void init() throws ServletException,

public void init(ServletConfig config) throws ServletException 

Executed once when the servlet is first loaded. Not called for each 

request. Use 

getInitParameter

 to read initialization parameters.

  public void service(HttpServletRequest request, 

public void service(

HttpServletResponse response) 

throws ServletException, IOException 

Called in a new thread by server for each request. Dispatches to 

doGet

, 

doPost

, etc. Do not override this method!

  public void doGet(HttpServletRequest request, 

public void doGet(

HttpServletResponse response) 

throws ServletException, IOException 

Handles 

GET

 requests. Override to provide your behavior.

  public void doPost(HttpServletRequest request, 

public void doPost(

HttpServletResponse response) 

throws ServletException, IOException 

Handles 

POST

 requests. Override to provide your behavior. If you want 

GET

 and 

POST

 to act identically, call 

doGet

 here.

  doPut, doTrace, doDelete, etc.

Handles the uncommon HTTP requests of 

PUT

, 

TRACE

, etc.

  public void destroy() 

Called when server deletes servlet instance. Not called after each 

request.

  public long getLastModified(HttpServletRequest request) 

Called by server when client sends conditional 

GET

 due to cached copy. 

See Section 2.8.

  SingleThreadModel

If this interface implemented, causes server to avoid concurrent 

invocations.

Second edition of this book: www.coreservlets.com; Sequel: www.moreservlets.com.

Servlet and JSP training courses by book's author: courses.coreservlets.com.