Java Tutorial/Servlet/Error Page
Содержание
Servlet Error Display
<source lang="java">
import java.io.*; import javax.servlet.*; import javax.servlet.http.*; import java.util.*; public class MyServlet extends HttpServlet {
public void doGet(HttpServletRequest req, HttpServletResponse res)
throws ServletException, IOException {
res.setContentType("text/html");
PrintWriter out = res.getWriter();
String code = null, message = null, type = null;
Object codeObj, messageObj, typeObj;
codeObj = req.getAttribute("javax.servlet.error.status_code");
messageObj = req.getAttribute("javax.servlet.error.message");
typeObj = req.getAttribute("javax.servlet.error.exception_type");
if (codeObj != null) code = codeObj.toString();
if (messageObj != null) message = messageObj.toString();
if (typeObj != null) type = typeObj.toString();
String reason = (code != null ? code : type);
out.println("<HTML>");
out.println("<HEAD><TITLE>" + reason + ": " + message + "</TITLE></HEAD>");
out.println("<BODY>");
out.println("" + reason + "
"); out.println("" + message + "
"); out.println("");
out.println("Error accessing " + req.getRequestURI() + "");
out.println("</BODY></HTML>");
}
}</source>
Servlet Error Page
<source lang="java">
import java.io.*; import javax.servlet.*; import javax.servlet.http.*; public class MyServlet extends HttpServlet {
public void doGet(HttpServletRequest req, HttpServletResponse res)
throws ServletException, IOException {
res.setContentType("text/html");
PrintWriter out = res.getWriter();
String code = null, message = null, type = null, uri = null;
Object codeObj, messageObj, typeObj;
Throwable throwable;
// Retrieve the three possible error attributes, some may be null
codeObj = req.getAttribute("javax.servlet.error.status_code");
messageObj = req.getAttribute("javax.servlet.error.message");
typeObj = req.getAttribute("javax.servlet.error.exception_type");
throwable = (Throwable)
req.getAttribute("javax.servlet.error.exception");
uri = (String)
req.getAttribute("javax.servlet.error.request_uri");
if (uri == null) {
uri = req.getRequestURI(); // in case there"s no URI given
}
// Convert the attributes to string values
if (codeObj != null) code = codeObj.toString();
if (messageObj != null) message = messageObj.toString();
if (typeObj != null) type = typeObj.toString();
// The error reason is either the status code or exception type
String reason = (code != null ? code : type);
out.println("<HTML>");
out.println("<HEAD><TITLE>" + reason + ": " + message +
"</TITLE></HEAD>");
out.println("<BODY>");
out.println("" + reason + "
"); out.println("" + message + "
"); out.println("");
if (throwable != null) {
throwable.printStackTrace(out);
}
out.println("");
out.println("");
out.println("Error accessing " + uri + "");
out.println("</BODY></HTML>");
}
}</source>
