package com.chengzhong.tools;
import java.io.*;
import javax.comm.CommPortIdentifier;
import javax.comm.*;
/**
*
* This bean provides some basic functions to implement full duplex
* information exchange through the serial port.
*
*/
public class SerialBean
{
public static String PortName;
public static CommPortIdentifier portId;
public static SerialPort serialPort;
public static OutputStream out;
public static InputStream in;
//保存讀數(shù)結(jié)果
public static String result="";
public static int openSignal=1;
/**
*
* Constructor
*
* @param PortID the ID of the serial to be used. 1 for COM1,
* 2 for COM2, etc.
*
*/
public SerialBean(int PortID)
{
 PortName = "COM" +PortID;
}
/**
*
* This function initialize the serial port for communication. It starts a
* thread which consistently monitors the serial port. Any signal captured
* from the serial port is stored into a buffer area.
*
*/
public int Initialize()
{
  openSignal=1;
  try
  {
  portId = CommPortIdentifier.getPortIdentifier(PortName);
  try
  {
  serialPort = (SerialPort)
  portId.open("Serial_Communication", 2000);
  } catch (PortInUseException e)
  {
    if(!SerialBean.portId.getCurrentOwner().equals("Serial_Communication"))
    {
      openSignal=2; //該串口被其它程序占用
    }else if(SerialBean.portId.getCurrentOwner().equals("Serial_Communication")){
      openSignal=1;
      return openSignal;
    }
   return openSignal;
  }
  //Use InputStream in to read from the serial port, and OutputStream
  //out to write to the serial port.
  try
  {
  in = serialPort.getInputStream();
  out = serialPort.getOutputStream();
  } catch (IOException e)
  {
     openSignal=3;  //輸入輸出流錯(cuò)誤
     return openSignal;
  }
  //Initialize the communication parameters to 9600, 8, 1, none.
  try
  {
  serialPort.setSerialPortParams(9600,
  SerialPort.DATABITS_8,
  SerialPort.STOPBITS_1,
  SerialPort.PARITY_NONE);
  } catch (UnsupportedCommOperationException e)
  {
     openSignal=4;  //參數(shù)不正確
     return openSignal;
  }
  } catch (NoSuchPortException e)
  {
     portId=null;
     openSignal=5; //沒有該串口
     return openSignal;
  }
  // when successfully open the serial port, create a new serial buffer,
  // then create a thread that consistently accepts incoming signals from
  // the serial port. Incoming signals are stored in the serial buffer.
// return success information
return openSignal;
}
/**
*
* This function returns a string with a certain length from the incoming
* messages.
*
* @param Length The length of the string to be returned.
*
*/
public static void ReadPort()
{
  SerialBean.result="";
int c;
try {
  if(in!=null){
    while(in.available()>0)
    {
      c = in.read();
      Character d = new Character((char) c);
      SerialBean.result=SerialBean.result.concat(d.toString());
    }
  }
} catch (IOException e) {
  // TODO Auto-generated catch block
  e.printStackTrace();
}
}
/**
*
* This function sends a message through the serial port.
*
* @param Msg The string to be sent.
*
*/
public static void WritePort(String Msg)
{
try
{
  if(out!=null){
    for (int i = 0; i < Msg.length(); i++)
       out.write(Msg.charAt(i));
  }
} catch (IOException e) {
  return;
}
}
/**
*
* This function closes the serial port in use.
*
*/
public void ClosePort()
{
 serialPort.close();
}
}

package com.chengzhong.dwr;
import java.io.IOException;
import com.chengzhong.tools.Arith;
import com.chengzhong.tools.SerialBean;
public class Put {
  //2011.9.17
  public String write(){
    //發(fā)送指令R，儀器發(fā)送一次凈重?cái)?shù)據(jù)
    SerialBean.WritePort("R");
    //讀取數(shù)據(jù)
    SerialBean.ReadPort();
    String temp=SerialBean.result.trim();  //我這里temp是形如 wn125.000kg 的數(shù)據(jù)
    if(!temp.equals("") && temp.length()==11)
    {
       return (change(temp)).toString();
    }else{
      return "";
    }
  }
  //響應(yīng)開始稱重
  public String startWeight(String num){
     int n=Integer.parseInt(num.trim());
     SerialBean SB = new SerialBean(n);
     SB.Initialize();
     return SerialBean.openSignal+""; //返回初始化信息
  }
//響應(yīng)停止稱重
  public void endWeight(){
    try {
      //關(guān)閉輸入、輸出流
      SerialBean.in.close();
      SerialBean.out.close();
    } catch (IOException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    }
    if(SerialBean.serialPort!=null){
      SerialBean.serialPort.close(); //關(guān)閉串口
    }
    SerialBean.serialPort=null;
    SerialBean.portId=null;
    SerialBean.result="";
  }
  /**
      * 將形如 wn125.000kg 格式的重量轉(zhuǎn)換為 125.000 (kg)(四舍五入，小數(shù)點(diǎn)后保留兩位)
   */
   public String change(String source){
     Double result=0.0;
     String s1=source.substring(2,9);
     try{
       result=Double.parseDouble(s1);
       result=Arith.round(result,2);
     }catch(Exception e){
       e.printStackTrace();
       return "";
     }
     return result.toString();
   }
}

package com.chengzhong.tools;
import java.math.BigDecimal;
/**
* 由于Java的簡單類型不能夠精確的對(duì)浮點(diǎn)數(shù)進(jìn)行運(yùn)算，這個(gè)工具類提供精
* 確的浮點(diǎn)數(shù)運(yùn)算，包括加減乘除和四舍五入。
*/
public class Arith{
  //默認(rèn)除法運(yùn)算精度
  private static final int DEF_DIV_SCALE = 10;
  //這個(gè)類不能實(shí)例化
  private Arith(){
  }
  /**
   * 提供精確的加法運(yùn)算。
   * @param v1 被加數(shù)
   * @param v2 加數(shù)
   * @return 兩個(gè)參數(shù)的和
   */
  public static double add(double v1,double v2){
    BigDecimal b1 = new BigDecimal(Double.toString(v1));
    BigDecimal b2 = new BigDecimal(Double.toString(v2));
    return b1.add(b2).doubleValue();
  }
  /**
   * 提供精確的減法運(yùn)算。
   * @param v1 被減數(shù)
   * @param v2 減數(shù)
   * @return 兩個(gè)參數(shù)的差
   */
  public static double sub(double v1,double v2){
    BigDecimal b1 = new BigDecimal(Double.toString(v1));
    BigDecimal b2 = new BigDecimal(Double.toString(v2));
    return b1.subtract(b2).doubleValue();
  }
  /**
   * 提供精確的乘法運(yùn)算。
   * @param v1 被乘數(shù)
   * @param v2 乘數(shù)
   * @return 兩個(gè)參數(shù)的積
   */
  public static double mul(double v1,double v2){
    BigDecimal b1 = new BigDecimal(Double.toString(v1));
    BigDecimal b2 = new BigDecimal(Double.toString(v2));
    return b1.multiply(b2).doubleValue();
  }
  /**
   * 提供（相對(duì)）精確的除法運(yùn)算，當(dāng)發(fā)生除不盡的情況時(shí)，精確到
   * 小數(shù)點(diǎn)以后10位，以后的數(shù)字四舍五入。
   * @param v1 被除數(shù)
   * @param v2 除數(shù)
   * @return 兩個(gè)參數(shù)的商
   */
  public static double div(double v1,double v2){
    return div(v1,v2,DEF_DIV_SCALE);
  }
  /**
   * 提供（相對(duì)）精確的除法運(yùn)算。當(dāng)發(fā)生除不盡的情況時(shí)，由scale參數(shù)指
   * 定精度，以后的數(shù)字四舍五入。
   * @param v1 被除數(shù)
   * @param v2 除數(shù)
   * @param scale 表示表示需要精確到小數(shù)點(diǎn)以后幾位。
   * @return 兩個(gè)參數(shù)的商
   */
  public static double div(double v1,double v2,int scale){
    if(scale<0){
      throw new IllegalArgumentException(
        "The scale must be a positive integer or zero");
    }
    BigDecimal b1 = new BigDecimal(Double.toString(v1));
    BigDecimal b2 = new BigDecimal(Double.toString(v2));
    return b1.divide(b2,scale,BigDecimal.ROUND_HALF_UP).doubleValue();
  }
  /**
   * 提供精確的小數(shù)位四舍五入處理。
   * @param v 需要四舍五入的數(shù)字
   * @param scale 小數(shù)點(diǎn)后保留幾位
   * @return 四舍五入后的結(jié)果
   */
  public static double round(double v,int scale){
    if(scale<0){
      throw new IllegalArgumentException(
        "The scale must be a positive integer or zero");
    }
    BigDecimal b = new BigDecimal(Double.toString(v));
    BigDecimal one = new BigDecimal("1");
    return b.divide(one,scale,BigDecimal.ROUND_HALF_UP).doubleValue();
  }
}

<script type="text/javascript" src="/ChengZhong/dwr/engine.js"></script>
<script type="text/javascript" src="/ChengZhong/dwr/util.js"></script>
<script type='text/javascript' src='/ChengZhong/dwr/interface/ss.js' ></script>
<script type='text/javascript' >
 var ID;
   function begin(){
    ID=window.setInterval('get()',500); //每隔半秒自動(dòng)調(diào)用 get(),取得毛重?cái)?shù)據(jù)填入文本框中
   }
 function get()
   {
    ss.write(readIt);  //調(diào)用dwr類 Put.java 中的write方法
   }
   function readIt(Data){
    if(Data!=null && Data!="")
    {
      document.getElementById("mzBF").value=Data;
        }
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