Java/Servlets/JNDI

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Email JNDI Filter

   <source lang="java">

import java.io.IOException; import java.io.PrintWriter; import javax.naming.Context; import javax.naming.InitialContext; import javax.naming.NamingException; import javax.mail.*; import javax.mail.internet.*; import javax.servlet.*; import javax.servlet.http.*; public class EmailJndiServlet extends HttpServlet { 

 private Session mailSession;
 public void init() throws ServletException {
       
        Context env = null;
   
      try{
          
            env = (Context) new InitialContext();
            
            mailSession = (Session) env.lookup("MyEmail");
            
            if (mailSession == null)
                throw new ServletException(
                  "MyEmail is an unknown JNDI object");
                  
            //close the InitialContext
            env.close();
            
       } catch (NamingException ne) { 
       
         try{ env.close();} catch (NamingException nex) { }
       
          throw new ServletException(ne);
       }
     
   }
 public void doPost(HttpServletRequest request, 
     HttpServletResponse response) throws ServletException,
         java.io.IOException {
   
     response.setContentType("text/html");
     java.io.PrintWriter out = response.getWriter();
     out.println(
     "<html><head><title>Email message sender</title></head><body>");
    
     String to = request.getParameter("to");
   
    String from = request.getParameter("from");
     String subject = request.getParameter("subject");
     String emailContent = request.getParameter("emailContent");
        
     try{
     
         sendMessage(to,from,subject,emailContent);
         
     } catch(Exception exc){
     
         throw new ServletException(exc.getMessage());
         
     }
   
   
       out.println(
"

The message was sent successfully

</body></html>"); 
   out.println("</body></html>");
   out.close();
    } //doPost
    
    public void doGet(HttpServletRequest request, 
     HttpServletResponse response) throws ServletException,
         java.io.IOException {
         
             doPost(request,response);
         
   }
    
 private void sendMessage(String to, String from,String subject, 
   String bodyContent) throws Exception {
   
     Message mailMsg = null;
    
      synchronized(mailSession){
      
         mailMsg = new MimeMessage(mailSession);//a new email message
      }
      InternetAddress[] addresses = null;
   
      try {
  
            if (to != null) {
       
               //throws "AddressException" if the "to" email address
               //violates RFC822 syntax
               addresses = InternetAddress.parse(to, false);
               mailMsg.setRecipients(Message.RecipientType.TO, addresses);
       
            } else {
       
                throw new MessagingException(
                    "The mail message requires a "To" address.");
       
           }
         
      if (from != null)
          mailMsg.setFrom(new InternetAddress(from));
      
          if (subject != null)
              mailMsg.setSubject(subject);
          if (bodyContent != null)
              mailMsg.setText(bodyContent);
       
          //Finally, send the mail message; throws a "SendFailedException" 
          //if any of the message"s recipients have an invalid adress
          Transport.send(mailMsg);
       
           } catch (Exception exc) {
   
               throw exc;
          }
   }//sendMessage

}//EmailJndiServlet 


 </source>



JNDI Filter

   <source lang="java">

import java.io.IOException; import javax.naming.Context; import javax.naming.InitialContext; import javax.naming.NamingException; import javax.servlet.Filter; import javax.servlet.FilterChain; import javax.servlet.FilterConfig; import javax.servlet.ServletException; import javax.servlet.ServletRequest; import javax.servlet.ServletResponse; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpSession; public class JndiFilter implements Filter { 

 private FilterConfig config;
 private Context env;
 public JndiFilter() {
 }
 public void init(FilterConfig filterConfig) throws ServletException {
   this.config = filterConfig;
   try {
     env = (Context) new InitialContext();
   } catch (NamingException ne) {
     throw new ServletException(ne);
   }
 }
 public void doFilter(ServletRequest request, ServletResponse response,
     FilterChain chain) throws IOException, ServletException {
   javax.mail.Session mailSession = null;
   try {
     mailSession = (javax.mail.Session) env.lookup("MyEmail");
   } catch (NamingException ne) {
   }
   HttpServletRequest hRequest = null;
   if (request instanceof HttpServletRequest) {
     hRequest = (HttpServletRequest) request;
     HttpSession hSession = hRequest.getSession();
     if (hSession != null)
       hSession.setAttribute("MyEmail", mailSession);
   }//if
   chain.doFilter(request, response);
 }// doFilter
 public void destroy() {
   /*
    * called before the Filter instance is removed from service by the web
    * container
    */
 }

} 


 </source>



Servlet JNDI and Bean

   <source lang="java">

import javax.naming.Context; import javax.naming.InitialContext; import javax.naming.NamingException; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; public class BeanServlet extends HttpServlet { 

 private StockPriceBean spbean;
 public void init() throws ServletException {
   Context env = null;
   try {
     // Compile error since there is no StockPriceBean.class
     // change the name according to your requirements
     env = (Context) new InitialContext().lookup("java:comp/env");
     spbean = (StockPriceBean) env.lookup("bean/pricebean");
     //close the InitialContext
     env.close();
     if (spbean == null)
       throw new ServletException(
           "bean/pricebean is an unknown JNDI object");
   } catch (NamingException ne) {
     try {
       env.close();
     } catch (NamingException nex) {
     }
     throw new ServletException(ne);
   }
 }
 public void doGet(HttpServletRequest request, HttpServletResponse response)
     throws ServletException, java.io.IOException {
   //set the MIME type of the response, "text/html"
   response.setContentType("text/html");
   //use a PrintWriter send text data to the client who has requested the
   // servlet
   java.io.PrintWriter out = response.getWriter();
   //Begin assembling the HTML content
   out.println("<html><head>");
   out.println("<title>Stock Price Fetcher</title></head><body>");
out.println("

Please submit a valid stock symbol

"); 
   //make sure method="post" so that the servlet service method
   //calls doPost in the response to this form submit
   out.println("<form method=\"post\" action =\""
       + request.getContextPath() + "/namingbean\" >");
out.println(""); out.println("
"); out.println("Stock symbol: "); 
   out.println("<input type=\"text\" name=\"symbol\" size=\"10\">");
out.println("
"); out.println("<input type=\"submit\" value=\"Submit Info\">
</form>"); 
   out.println("</body></html>");
   out.close();
 } //end doGet
 public void doPost(HttpServletRequest request, HttpServletResponse response)
     throws java.io.IOException {
   String symbol;//this will hold the stock symbol
   float price = 0f;
   symbol = request.getParameter("symbol");
   boolean isValid = (symbol == null || symbol.length() < 1) ? false
       : true;
   //set the MIME type of the response, "text/html"
   response.setContentType("text/html");
   //use a PrintWriter send text data to the client who has requested the
   // servlet
   java.io.PrintWriter out = response.getWriter();
   //Begin assembling the HTML content
   out.println("<html><head>");
   out.println("<title>Latest stock value</title></head><body>");
   if ((!isValid) || spbean == null) {
out.println("

Sorry, the stock symbol parameter was either empty or null

"); 
   } else {
out.println("

Here is the latest value of " + symbol + "

"); 
     spbean.setSymbol(symbol);
     price = spbean.getLatestPrice();
     out.println((price < 1 ? "The symbol is probably invalid." : ""
         + price));
   }
   out.println("</body></html>");
 }// doPost

}//BeanServlet 


 </source>



Use JNDI to get database connection or data source

   <source lang="java">

import java.io.IOException; import java.io.PrintWriter; import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; import java.text.DateFormat; import java.text.SimpleDateFormat; import java.util.Date; import javax.naming.InitialContext; import javax.naming.NamingException; import javax.servlet.Servlet; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.sql.DataSource; public class Main extends HttpServlet implements Servlet { 

 protected void doGet(HttpServletRequest request, HttpServletResponse response)
     throws ServletException, IOException {
   DateFormat dateFormat = new SimpleDateFormat("dd/MM/yyyy");
   response.setContentType("text/html");
   PrintWriter writer = response.getWriter();
   Connection connection = getConnection();
   if (connection != null) {
     String sql = "SELECT SYSDATE FROM DUAL";
     try{
     PreparedStatement statement = connection.prepareStatement(sql);
     ResultSet rs = statement.executeQuery();
     while (rs.next()) {
       Date date = rs.getDate("SYSDATE");
       writer.println("The current date is " + dateFormat.format(date));
     }
     connection.close();
     }catch(Exception e){
       System.out.println(e);
     }
   }
 }
 protected void doPost(HttpServletRequest request, HttpServletResponse response)
     throws ServletException, IOException {
 }
 private Connection getConnection() {
   Connection connection = null;
   try {
     InitialContext context = new InitialContext();
     DataSource dataSource = (DataSource) context.lookup("jdbc/DataSource");
     connection = dataSource.getConnection();
   } catch (NamingException e) {
     e.printStackTrace();
   } catch (SQLException e) {
     e.printStackTrace();
   }
   return connection;
 }

} 

 </source>



Web JNDI

   <source lang="java">

import javax.naming.Context; import javax.naming.InitialContext; import javax.naming.NamingException; import javax.rmi.PortableRemoteObject; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; public class WebJndiServlet extends HttpServlet { 

 public void doGet(HttpServletRequest request, HttpServletResponse response)
     throws ServletException, java.io.IOException {
   String state = request.getParameter("state");
   Context env = null;
   Abbrev abbrev = null;
   AbbrevHome home = null;
   try {
     env = (Context) new InitialContext();
     Object localH = env.lookup("AbbrevHome");
     home = (AbbrevHome) PortableRemoteObject.narrow(localH,
         AbbrevHome.class);
     //close the InitialContext
     env.close();
     if (home == null)
       throw new ServletException(
           "AbbrevHome is an unknown JNDI object");
     abbrev = (Abbrev) PortableRemoteObject.narrow(home.create(),
         Abbrev.class);
   } catch (NamingException ne) {
     try {
       env.close();
     } catch (NamingException nex) {
     }
     throw new ServletException(ne);
   } catch (javax.ejb.CreateException ce) {
     throw new ServletException(ce);
   }
   //set the MIME type of the response, "text/html"
   response.setContentType("text/html");
   //use a PrintWriter send text data to the client who has requested the
   // servlet
   java.io.PrintWriter out = response.getWriter();
   //Begin assembling the HTML content
   out.println("<html><head>");
   out.println("<title>State abbreviations</title></head><body>");
out.println("

Here is the state"s abbreviation

"); 
   if (state != null)
     out.println(abbrev.getAbbreviation(state.toUpperCase()));
   try {
     abbrev.remove();
   } catch (javax.ejb.RemoveException re) {
   }
   out.println("</body></html>");
   out.close();
 } //end doGet
 public void doPost(HttpServletRequest request, HttpServletResponse response)
     throws ServletException, java.io.IOException {
   doGet(request, response);
 }// doPost

}//BeanServlet 


 </source>
Источник — «http://www.jexp.ru/index.php?title=Java/Servlets/JNDI&oldid=6281»