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error: The value for the useBean class attribute is invalid

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Join Date: Nov 2006

Posts: 38

Reputation: apontutul is an unknown quantity at this point

Solved Threads: 1

apontutul

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error: The value for the useBean class attribute is invalid

Sep 7th, 2007

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<html>
<head>
<title>Pie Chart Demo</title>
</head>
 
<jsp:useBean id="myChart"  class="classes.beans.votepie" scope="session" />
 
<body>
<h2>Vote Results Pie-chart</h2>
 
<%String chartViewer = myChart.getvoteserve(request, response);%>
 
<img src="<%=chartViewer%>" border=0 usemap="#imageMap">
 
</body>
</html>

accessing this above viewrst.jsp file shows the following error:

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HTTP Status 500 - 

type Exception report
message 
description The server encountered an internal error () that prevented it from fulfilling this request.
exception 
org.apache.jasper.JasperException: /viewrst.jsp(6,0) The value for the useBean class attribute classes.beans.votepie is invalid.
	org.apache.jasper.compiler.DefaultErrorHandler.jspError(DefaultErrorHandler.java:40)
	org.apache.jasper.compiler.ErrorDispatcher.dispatch(ErrorDispatcher.java:407)
	org.apache.jasper.compiler.ErrorDispatcher.jspError(ErrorDispatcher.java:148)
	org.apache.jasper.compiler.Generator$GenerateVisitor.visit(Generator.java:1200)
	org.apache.jasper.compiler.Node$UseBean.accept(Node.java:1155)
	org.apache.jasper.compiler.Node$Nodes.visit(Node.java:2336)
	org.apache.jasper.compiler.Node$Visitor.visitBody(Node.java:2386)
	org.apache.jasper.compiler.Node$Visitor.visit(Node.java:2392)
	org.apache.jasper.compiler.Node$Root.accept(Node.java:489)
	org.apache.jasper.compiler.Node$Nodes.visit(Node.java:2336)
	org.apache.jasper.compiler.Generator.generate(Generator.java:3394)
	org.apache.jasper.compiler.Compiler.generateJava(Compiler.java:210)
	org.apache.jasper.compiler.Compiler.compile(Compiler.java:306)
	org.apache.jasper.compiler.Compiler.compile(Compiler.java:286)
	org.apache.jasper.compiler.Compiler.compile(Compiler.java:273)
	org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:566)
	org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:308)
	org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:320)
	org.apache.jasper.servlet.JspServlet.service(JspServlet.java:266)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:803)

this is the web.xml file

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<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE web-app
    PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.2//EN"
    "http://java.sun.com/j2ee/dtds/web-app_2_2.dtd">
 
<web-app>
  <servlet>
    <servlet-name>voteserve</servlet-name>
    <servlet-class>classes.servlets.voteserve</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>voteserve</servlet-name>
    <url-pattern>/servlet/voteserve</url-pattern>
  </servlet-mapping>
</web-app>

.......what or where is going wrong..please help

•

Join Date: Nov 2006

Posts: 38

Reputation: apontutul is an unknown quantity at this point

Solved Threads: 1

apontutul

Offline

Light Poster

Re: error: The value for the useBean class attribute is invalid

Sep 7th, 2007

giving all the concerned files so that it will be helpful for u to understand.
this is the bean file:votepie.java. it is used to create a chart. the class file is under WEB-INF/classes/beans folder.

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package classes.beans;
 
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.*;
import org.jfree.data.jdbc.*;
import org.jfree.data.general.*;
 
import java.io.*;
import java.awt.*;
import java.util.*;
import java.awt.image.*;
import org.jfree.data.*;
import org.jfree.chart.*;
import org.jfree.chart.plot.*;
import org.jfree.chart.urls.*;
import org.jfree.chart.entity.*;
import javax.servlet.*;
import javax.servlet.http.*;
import org.jfree.data.general.DefaultPieDataset;
import org.jfree.chart.ChartFactory;
import org.jfree.chart.ChartUtilities.*;
import org.jfree.chart.imagemap.*;
import java.io.PrintWriter.*;
import java.lang.String.*;
import org.jfree.chart.ChartRenderingInfo.*;
 
 
 
public class votepie {
	
	
	PreparedStatement st;
	
			
	public PieDataset readData() {
		
		JDBCPieDataset data = null;
		String url = "jdbc:mysql://localhost/vote";
		Connection con;
		try {
		Class.forName("com.mysql.jdbc.Driver");
		}
		catch (ClassNotFoundException e) {
		System.err.print("ClassNotFoundException: ");
		System.err.println(e.getMessage());
		}
		 
		try {
			ResultSet rs = st.executeQuery();
			int id = rs.getInt("poll_id");
		con = DriverManager.getConnection(url, "vote", "vote001");
		data = new JDBCPieDataset(con);
				
		st  = con.prepareStatement ("SELECT option_text, counter FROM VOTE_VOTES where poll_id=?");
		st.setInt(1, id);
		rs = st.executeQuery();
				
		//data.executeQuery(sql);
		con.close();
		}
		catch (SQLException e) {
		System.err.print("SQLException: ");
		System.err.println(e.getMessage());
		}
		catch (Exception e) {
		System.err.print("Exception: ");
		System.err.println(e.getMessage());
		}
		return data;
		}
	
	
	public String getChartViewer(HttpServletRequest request, HttpServletResponse response) {
	    votepie pd = new votepie();
		
	    // create the chart...
	    JFreeChart chart = ChartFactory.createPieChart(
	          "Vote Result Pie Chart",  // chart title
	          pd.readData(),             // data
	          true,                // include legend
	          true,
	          false
	    );
 
	    // set the background color for the chart...
	    chart.setBackgroundPaint(Color.cyan);
	    PiePlot plot = (PiePlot) chart.getPlot();
	    plot.setNoDataMessage("No data available");
	     
	    // set drilldown capability...
	    //plot.setURLGenerator(new StandardPieURLGenerator("Bar3DDemo.jsp","section"));
	    //plot.setLabelGenerator(null);
 
	    // OPTIONAL CUSTOMISATION COMPLETED.
 
	    ChartRenderingInfo info = null;
	    HttpSession session = request.getSession();
	    try {
 
	      //Create RenderingInfo object
	      response.setContentType("text/html");
	      info = new ChartRenderingInfo(new StandardEntityCollection());
	      BufferedImage chartImage = chart.createBufferedImage(640, 400, info);
 
	      // putting chart as BufferedImage in session, 
	      // thus making it available for the image reading action Action.
	      session.setAttribute("chartImage", chartImage);
 
	      PrintWriter writer = new PrintWriter(response.getWriter());
	      ChartUtilities.writeImageMap(writer, "imageMap", info, true);
	      writer.flush();
	    
	    }
	    catch (Exception e) {
	       // handle your exception here
	    }
	   
	    String pathInfo = "http://";
	    pathInfo += request.getServerName();
	    int port = request.getServerPort();
	    pathInfo += ":"+String.valueOf(port);
	    pathInfo += request.getContextPath();
	    String chartViewer = pathInfo + "/servlet/ChartViewer";
	    return chartViewer;
	  }
	}

package classes.beans;
 
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.*;
import org.jfree.data.jdbc.*;
import org.jfree.data.general.*;
 
import java.io.*;
import java.awt.*;
import java.util.*;
import java.awt.image.*;
import org.jfree.data.*;
import org.jfree.chart.*;
import org.jfree.chart.plot.*;
import org.jfree.chart.urls.*;
import org.jfree.chart.entity.*;
import javax.servlet.*;
import javax.servlet.http.*;
import org.jfree.data.general.DefaultPieDataset;
import org.jfree.chart.ChartFactory;
import org.jfree.chart.ChartUtilities.*;
import org.jfree.chart.imagemap.*;
import java.io.PrintWriter.*;
import java.lang.String.*;
import org.jfree.chart.ChartRenderingInfo.*;
 
 
 
public class votepie {
	
	
	PreparedStatement st;
	
			
	public PieDataset readData() {
		
		JDBCPieDataset data = null;
		String url = "jdbc:mysql://localhost/vote";
		Connection con;
		try {
		Class.forName("com.mysql.jdbc.Driver");
		}
		catch (ClassNotFoundException e) {
		System.err.print("ClassNotFoundException: ");
		System.err.println(e.getMessage());
		}
		 
		try {
			ResultSet rs = st.executeQuery();
			int id = rs.getInt("poll_id");
		con = DriverManager.getConnection(url, "vote", "vote001");
		data = new JDBCPieDataset(con);
				
		st  = con.prepareStatement ("SELECT option_text, counter FROM VOTE_VOTES where poll_id=?");
		st.setInt(1, id);
		rs = st.executeQuery();
				
		//data.executeQuery(sql);
		con.close();
		}
		catch (SQLException e) {
		System.err.print("SQLException: ");
		System.err.println(e.getMessage());
		}
		catch (Exception e) {
		System.err.print("Exception: ");
		System.err.println(e.getMessage());
		}
		return data;
		}
	
	
	public String getChartViewer(HttpServletRequest request, HttpServletResponse response) {
	    votepie pd = new votepie();
		
	    // create the chart...
	    JFreeChart chart = ChartFactory.createPieChart(
	          "Vote Result Pie Chart",  // chart title
	          pd.readData(),             // data
	          true,                // include legend
	          true,
	          false
	    );
 
	    // set the background color for the chart...
	    chart.setBackgroundPaint(Color.cyan);
	    PiePlot plot = (PiePlot) chart.getPlot();
	    plot.setNoDataMessage("No data available");
	     
	    // set drilldown capability...
	    //plot.setURLGenerator(new StandardPieURLGenerator("Bar3DDemo.jsp","section"));
	    //plot.setLabelGenerator(null);
 
	    // OPTIONAL CUSTOMISATION COMPLETED.
 
	    ChartRenderingInfo info = null;
	    HttpSession session = request.getSession();
	    try {
 
	      //Create RenderingInfo object
	      response.setContentType("text/html");
	      info = new ChartRenderingInfo(new StandardEntityCollection());
	      BufferedImage chartImage = chart.createBufferedImage(640, 400, info);
 
	      // putting chart as BufferedImage in session, 
	      // thus making it available for the image reading action Action.
	      session.setAttribute("chartImage", chartImage);
 
	      PrintWriter writer = new PrintWriter(response.getWriter());
	      ChartUtilities.writeImageMap(writer, "imageMap", info, true);
	      writer.flush();
	    
	    }
	    catch (Exception e) {
	       // handle your exception here
	    }
	   
	    String pathInfo = "http://";
	    pathInfo += request.getServerName();
	    int port = request.getServerPort();
	    pathInfo += ":"+String.valueOf(port);
	    pathInfo += request.getContextPath();
	    String chartViewer = pathInfo + "/servlet/ChartViewer";
	    return chartViewer;
	  }
	}

this is the servlet file: voteserve.java..the class file is under WEB-INF/classes/servlets folder.

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package classes.servlets;
 
import java.io.*;
import java.awt.image.*;
import javax.servlet.*;
import javax.servlet.http.*;
import com.keypoint.PngEncoder;
 
public class voteserve extends HttpServlet {
 
	  public void init() throws ServletException {
	  }
 
	  //Process the HTTP Get request
	  public void doGet(HttpServletRequest request, HttpServletResponse response)
	         throws ServletException, IOException {
 
	   // get the chart from session
	   HttpSession session = request.getSession();
	   BufferedImage chartImage = (BufferedImage) session.getAttribute("chartImage");
 
	   // set the content type so the browser can see this as a picture
	   response.setContentType("image/png");
 
	   // send the picture
	   PngEncoder encoder = new PngEncoder(chartImage, false, 0, 9);
	   response.getOutputStream().write(encoder.pngEncode());
	   
	  }
 
	  //Process the HTTP Post request
	  public void doPost(HttpServletRequest request, HttpServletResponse response)
	         throws ServletException, IOException {
	    doGet(request, response);
	  }
 
	  //Process the HTTP Put request
	  public void doPut(HttpServletRequest request, HttpServletResponse response)
	         throws ServletException, IOException {
	  }
 
	  //Clean up resources
	  public void destroy() {
	  }
 
	}

guys please plz help me out....thanks

•

Join Date: Mar 2008

Posts: 1

Reputation: safaa is an unknown quantity at this point

Solved Threads: 0

safaa

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Newbie Poster

Re: error: The value for the useBean class attribute is invalid

Mar 13th, 2008

Also I have the same problem in my project, but I'm sure that the connection is satisfied with my access data Base , because the project execute only file that retrieve data from the data Base, but it doesn't execute the other functions of log-in , update & delete functions.
Here is the error for the log in page:

type Exception report

message

description The server encountered an internal error () that prevented it from fulfilling this request.

exception

org.apache.jasper.JasperException: /jsp/MemberLogin.jsp(11,0) The value for the useBean class attribute com.mySite.Memberbean is invalid.
org.apache.jasper.compiler.DefaultErrorHandler.jspError(DefaultErrorHandler.java:39)
org.apache.jasper.compiler.ErrorDispatcher.dispatch(ErrorDispatcher.java:405)
org.apache.jasper.compiler.ErrorDispatcher.jspError(ErrorDispatcher.java:146)
org.apache.jasper.compiler.Generator$GenerateVisitor.visit(Generator.java:1223)
org.apache.jasper.compiler.Node$UseBean.accept(Node.java:1116)
org.apache.jasper.compiler.Node$Nodes.visit(Node.java:2163)
org.apache.jasper.compiler.Node$Visitor.visitBody(Node.java:2213)
org.apache.jasper.compiler.Node$Visitor.visit(Node.java:2219)
org.apache.jasper.compiler.Node$Root.accept(Node.java:456)
org.apache.jasper.compiler.Node$Nodes.visit(Node.java:2163)
org.apache.jasper.compiler.Generator.generate(Generator.java:3270)
org.apache.jasper.compiler.Compiler.generateJava(Compiler.java:189)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:286)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:267)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:255)
org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:556)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:293)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:291)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:241)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)

note The full stack trace of the root cause is available in the Apache Tomcat/5.5.9 logs.