JSP error & Java class for rs232

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  • Dan

    JSP error & Java class for rs232

    I wnat to see in browser an status from an device connected on rs232
    port

    The java class for read from serial port is:

    //Serial.java
    import java.io.*;
    import java.util.*;
    import java.lang.*;
    import javax.comm.*;


    public class Serial implements SerialPortEvent Listener
    {

    SerialPort port;
    CommPortIdentif ier ID;
    InputStream in;
    OutputStream out;
    String text1="ok";

    public void alarm(){

    try
    {
    ID = CommPortIdentif ier.getPortIden tifier("COM1");
    port = (SerialPort)ID. open("alarm",10 00);
    in = port.getInputSt ream();
    out = port.getOutputS tream();
    port.notifyOnDa taAvailable(tru e);
    port.setSerialP ortParams (19200, port.DATABITS_8 , port.STOPBITS_1 ,
    port.PARITY_NON E);
    port.setFlowCon trolMode(port.F LOWCONTROL_NONE );
    }
    catch (Exception e) {}

    }



    public void serialEvent(Ser ialPortEvent e)
    {
    int data = 0;
    String text1;

    switch(e.getEve ntType())
    {
    case SerialPortEvent .DATA_AVAILABLE :
    try
    {
    while (in.available() > 0)
    {
    data=in.read();
    if ('S' == (char)data)
    {
    data=in.read();
    update_status(d ata);
    }
    }
    }
    catch (IOException ev) {}
    break;
    }
    }





    public String update_status (int s)
    {
    int temp = s;
    int val = temp & 0x01;

    if (val==0x01)
    text1 = "ok";
    else
    text1 = "not ok";

    return text1;
    }

    }//end class

    Tha jsp page is :
    //RS232.jsp

    <%@ page import="Serial" %>
    <HTML>
    <HEAD>
    <TITLE>Using a JavaBean</TITLE>
    </HEAD>

    <BODY>


    <% Serial rs232 = new Serial(); %>

    The status is: <%= rs232.update_st atus() %>

    </BODY>
    </HTML>



    I started Apache Tomcat 5.0 server (run on Winxp); I put RS232.jsp in
    "webapps/Root" and Serial.class in "webapps/Root/WEB-INF/classes

    On executing "http://localhost/RS232.jsp" I have an error :

    //............... .....
    org.apache.jasp er.JasperExcept ion: Unable to compile class for JSP

    An error occurred at line: -1 in the jsp file: null

    Generated servlet error:
    [javac] Compiling 1 source file

    C:\Tomcat5\work \Catalina\local host\_\org\apac he\jsp\RS232_js p.java:6:
    '.' expected
    import Serial;
    ^
    1 error
    //............... ............

    What can be wrong????
  • hani
    New Member
    • Mar 2006
    • 4

    #2
    hello, i'm hani. i'm learning to use servlet in read serial port. i'll try to run your program. the error is it can't read update_status() . only. have you figure what's wrong with the code. just want to know. thank you

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