📄 periodictaskservlet.java

📁 RESIN 3.2 最新源码
💻 JAVA
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package example;import com.caucho.util.ThreadPool;import com.caucho.util.ThreadTask;import java.io.*;import java.text.DateFormat;import java.text.NumberFormat;import java.util.Date;import java.util.logging.Level;import java.util.logging.Logger;import java.util.concurrent.Executor;import javax.servlet.*;import javax.servlet.http.*;import javax.webbeans.In;/** * A Servlet that provides a user interface for managing a PeriodicTask. */public class PeriodicTaskServlet extends HttpServlet {  static protected final Logger log =     Logger.getLogger(PeriodicTaskServlet.class.getName());  int _refreshRate = 5;  @In  private Executor _executor;  @In  private PeriodicTask _periodicTask;  private NumberFormat _numberFormat ;  private DateFormat _dateFormat ;  public PeriodicTaskServlet()  {  }  /**   * The refresh rate in seconds to send to the browser to cause automatic   * refresh, default 5, <= 0 disables.   */  public void setRefreshRate(int refreshRate)  {    _refreshRate = 5;  }  public void init()    throws ServletException  {    _numberFormat = NumberFormat.getInstance();    _dateFormat = DateFormat.getInstance();    String p;    p = getInitParameter("refresh-rate");    if (p != null)      setRefreshRate(Integer.parseInt(p));  }  protected void doGet(HttpServletRequest request, HttpServletResponse response)    throws ServletException, IOException  {    final PeriodicTask task = _periodicTask;    String msg = null;    if (request.getParameter("RUN") != null) {      if (task.isActive())        msg = "Already active.";      else {        // It's tricky to start another Thread from a Servlet.  Here        // the Resin ThreadPool class is used.  ThreadPool will interrupt a        // thread and stop it if it runs for too long.        ThreadTask threadTask = new ThreadTask() {          public void run()          {            task.run();          }        };        _executor.execute(threadTask);        Thread.yield();        response.sendRedirect(request.getRequestURI());      }    }    response.setContentType("text/html");    PrintWriter out = response.getWriter();    // stop browser from caching the page    response.setHeader("Cache-Control","no-cache,post-check=0,pre-check=0");    response.setHeader("Pragma","no-cache");    response.setHeader("Expires","Thu,01Dec199416:00:00GMT");    if (_refreshRate > 0) {      response.addHeader( "refresh", String.valueOf(_refreshRate) + "; URL=" + request.getRequestURI());    }    out.println("<html>");    out.println("<head><title>PeriodicTask</title></head>");    out.println("<body>");    out.println("<h1>PeriodicTask</h1>");    if (msg != null) {      out.print("<p><b>");      printSafeHtml(out,msg);      out.println("</b></p>");    }    out.println("<table border='0'>");    printHeading(out,"configuration");    printPeriod(out,"estimated-average-time:", task.getEstimatedAverageTime());    printHeading(out,"statistics");    printField(out,"active", task.isActive());    printPeriod(out,"estimated-time-remaining",task.getEstimatedTimeRemaining());    printDate(out,"last-active-time", task.getLastActiveTime());    printField(out,"total-active-count", task.getTotalActiveCount());    printPeriod(out,"total-active-time", task.getTotalActiveTime());    printPeriod(out,"average-active-time", task.getAverageActiveTime());    printHeading(out,"actions");    printActions(out,new String[][] { {"RUN", "Run"} });    out.println("</table border='0'>");    out.println("</body>");    out.println("</html>");  }  protected void printHeading(PrintWriter out, String heading)  {    out.print("<tr><td colspan='2'><h2>");    printSafeHtml(out,heading);    out.println("</h2></td></tr>");  }    protected void printField(PrintWriter out, String name, String value)  {    out.print("<tr><td>");    printSafeHtml(out,name);    out.print("</td><td>");    printSafeHtml(out,value);    out.print("</td></tr>");  }  protected void printField(PrintWriter out, String name, boolean value)  {    printField(out,name, value == true ? "true" : "false");  }  protected void printField(PrintWriter out, String name, long value)  {    printField(out,name, _numberFormat.format(value));  }  protected void printDate(PrintWriter out, String name, long date)  {    printField(out,name, _dateFormat.format(new Date(date)));  }  protected void printPeriod(PrintWriter out, String name, long millis)  {    double sec = millis / 1000;    printField(out,name, _numberFormat.format(millis) + "sec");  }  protected void printActions(PrintWriter out, String[][] actions)  {    out.println("<tr><td colspan='2'><form>");    for (int i = 0; i < actions.length; i++) {      out.print("<input type='submit' name='");      printSafeHtml(out,actions[i][0]);      out.print("' value='");      printSafeHtml(out,actions[i][1]);      out.println("'/>");    }    out.println("</form></td></tr>");  }  protected void printSafeHtml(PrintWriter out, String text)  {    int len = text.length();    for (int i = 0; i < len; i++) {      char ch = text.charAt(i);      switch (ch) {        case '<':          out.print("&lt;");          break;        case '>':          out.print("&gt;");          break;        case '&':          out.print("&amp;");          break;        default:          out.print(ch);      }    }  }}
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