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import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class RequestDisplay extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, java.io.IOException {
ContextObject obj = (ContextObject) request
.getAttribute("com.java2s.RequestObject");
//display the attribute's Map keys
response.setContentType("text/html");
java.io.PrintWriter out = response.getWriter();
out
.println("<html><head><title>Request Attribute</title></head><body>");
out.println("<h2>Request attribute values</h2>");
if (obj != null)
out.println(obj.getValues());
out.println("</body></html>");
} //end doGet
}
//ContextObject.java
class ContextObject {
private Map map;
public ContextObject() {
map = Collections.synchronizedMap(new HashMap());
}
public void put(Object key, Object value) {
if (key == null || value == null)
throw new IllegalArgumentException(
"Invalid parameters passed to ContextObject.put");
map.put(key, value);
}
public Map getMap() {
return map;
}
public String getValues() {
StringBuffer buf = new StringBuffer("");
Set set = map.keySet();
synchronized (map) {
Iterator i = set.iterator();
while (i.hasNext())
buf.append((String) i.next() + "<br>");
}
return buf.toString();
}
public String toString() {
return getClass().getName() + "[ " + map + " ]";
}
}
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