Java/Servlets/JNDI

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Версия от 18:01, 31 мая 2010; (обсуждение)
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Email JNDI Filter

 
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(
        "<h2>The message was sent successfully</h2></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





JNDI Filter

 
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
     */
  }
}





Servlet JNDI and Bean

 
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("<h2>Please submit a valid stock symbol</h2>");
    //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("<table border=\"0\"><tr><td valign=\"top\">");
    out.println("Stock symbol: </td>  <td valign=\"top\">");
    out.println("<input type=\"text\" name=\"symbol\" size=\"10\">");
    out.println("</td></tr><tr><td valign=\"top\">");
    out.println("<input type=\"submit\" value=\"Submit Info\"></td></tr>");
    out.println("</table></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("<h2>Sorry, the stock symbol parameter was either empty or null</h2>");
    } else {
      out.println("<h2>Here is the latest value of " + symbol + "</h2>");
      spbean.setSymbol(symbol);
      price = spbean.getLatestPrice();
      out.println((price < 1 ? "The symbol is probably invalid." : ""
          + price));
    }
    out.println("</body></html>");
  }// doPost
}//BeanServlet





Use JNDI to get database connection or data source

 
 
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;
  }
}





Web JNDI

 
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("<h2>Here is the state"s abbreviation</h2>");
    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


Источник — «http://jexp.ru/index.php?title=Java/Servlets/JNDI&oldid=6280»