ServletContextAttributeListener
ServletContext context = getServletContext();
context.setAttribute(“attrName”, “attrValue”);
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import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Enumeration;
public class HelloWorld extends HttpServlet {
private static final long serialVersionUID = -9037964452251358377L;
public HelloWorld() {
System.out.println("servlet.helloWorld.constructor");
}
public void init() {
System.out.println("servlet.helloWorld.init.");
}
public void destroy() {
System.out.println("servlet.helloWorld.destroy.");
}
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
System.out.println("servlet.helloWorld.doGet.start");
// get, query string
String queryString = request.getQueryString();
// header name
printHeaderName(request);
// get parameter
System.out.println("parameter.foo= " + request.getParameter("foo"));
// query string
System.out.println("query string: " + queryString);
// character encoding
System.out.println("encoding: " + request.getCharacterEncoding());
//init param
System.out.println("init param: " + getInitParameter("ipn"));
//set context attribute
ServletContext context = getServletContext();
context.setAttribute("attrName", "attrValue");
response.setContentType("text/html");
PrintWriter out = response.getWriter();
out.println("<html><head><title>");
out.println("This is my first Servlet");
out.println("</title></head><body>");
out.println("Hello,World!, Servlet!");
out.println("</body></html>");
System.out.println("servlet.helloWorld.doGet.end");
}
private void printHeaderName(HttpServletRequest request) {
Enumeration enumstr = request.getHeaderNames();
while (enumstr.hasMoreElements()) {
String name = (String) enumstr.nextElement();
System.out.println("header: " + name + " = "
+ request.getHeader(name));
}
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
// post, request form
// String form = request.get;
}
}
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