Java：按位AND创建无符号字节
[英]Java: Unsigned byte creation by bit-wise AND
问题描述
我想创建一个位阵列，它将通过串行RS232发送到Arduino来控制输出引脚。
我这样做是通过创建复选框，当选中时会发送一个字节，每个位指的是一个引脚（开或关）。
我已经使用逐位AND操作和打印系统输出实现了前8个复选框的代码，以确认我得到了正确的位模式。
它适用于前7个复选框，但第8个不起作用，因为java字节已签名，不允许我为字节值分配'255'。 有没有解决的办法？
重要的代码是这一点：
private void createOutputChars(){
byte outputByte1 = 0;
byte testByte = 1;
for (int x = 0;x < 8;x++){
if (digitalPinOutputArray[x].isSelected()) {
outputByte1 += (byte) (testByte);
}
testByte = (byte) (testByte << 1);
}
printByteArray(outputByte1);
}
private void printByteArray(int inputByte) {
// print out 1 or 0
byte comparison = 0x1;
for (int x = 0;x < 8;x++)
{
if ((inputByte & comparison) > 0) {
System.out.print("1");
}
else {System.out.print("0");}
comparison = (byte) (comparison << 1);
}
System.out.println();
}
完整的可编译Java代码是这样的：
/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/
package my.ArduinoGUI;
import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
public class ArduinoGUI extends javax.swing.JFrame {
/**
* Creates new form ArduinoGUI
*/
public ArduinoGUI() {
initCustomComponents();
initComponents();
}
/**
* This method is called from within the constructor to initialize the form.
* WARNING: Do NOT modify this code. The content of this method is always
* regenerated by the Form Editor.
*/
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
buttonGroup1 = new javax.swing.ButtonGroup();
jPanel1 = new javax.swing.JPanel();
digitalPinPanel = new javax.swing.JPanel(new GridLayout(0, 3));
jPanel3 = new javax.swing.JPanel(new GridLayout(0, 1));
jPanel2 = new javax.swing.JPanel();
jProgressBar1 = new javax.swing.JProgressBar();
jProgressBar2 = new javax.swing.JProgressBar();
jProgressBar3 = new javax.swing.JProgressBar();
jProgressBar4 = new javax.swing.JProgressBar();
jProgressBar5 = new javax.swing.JProgressBar();
jProgressBar6 = new javax.swing.JProgressBar();
jLabel1 = new javax.swing.JLabel();
jLabel2 = new javax.swing.JLabel();
jLabel3 = new javax.swing.JLabel();
jLabel4 = new javax.swing.JLabel();
jLabel5 = new javax.swing.JLabel();
jLabel6 = new javax.swing.JLabel();
jLabel7 = new javax.swing.JLabel();
jLabel8 = new javax.swing.JLabel();
jProgressBar7 = new javax.swing.JProgressBar();
jProgressBar8 = new javax.swing.JProgressBar();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
jPanel1.setBorder(javax.swing.BorderFactory.createTitledBorder("Outputs"));
jPanel1.setName("Outputs"); // NOI18N
javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
jPanel1.setLayout(jPanel1Layout);
jPanel1Layout.setHorizontalGroup(
jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 209, Short.MAX_VALUE)
);
jPanel1Layout.setVerticalGroup(
jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 106, Short.MAX_VALUE)
);
digitalPinPanel.setBorder(javax.swing.BorderFactory.createTitledBorder("Digital Pin State"));
digitalPinPanel.addMouseListener(new java.awt.event.MouseAdapter() {
public void mouseReleased(java.awt.event.MouseEvent evt) {
digitalPinPanelMouseReleased(evt);
}
});
digitalPinLabelArray = new javax.swing.JLabel[digitalPinTotal];
digitalPinRadioButtonArray = new javax.swing.JRadioButton[digitalPinTotal][2];
digitalPinGroupArray = new javax.swing.ButtonGroup[digitalPinTotal];
for(int x = 0; x < digitalPinTotal ; x++) {
digitalPinGroupArray[x] = new javax.swing.ButtonGroup(); // populate button group
digitalPinLabelArray[x] = new javax.swing.JLabel(); // populate label array
digitalPinLabelArray[x].setText("Pin " + (x +2));
digitalPinPanel.add(digitalPinLabelArray[x]); // add label to panel
for(int y = 0; y < 2; y++){
digitalPinRadioButtonArray[x][y] = new javax.swing.JRadioButton(); // populate radio button array
digitalPinRadioButtonArray[x][y].addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e)
{
//Execute when button is pressed
System.out.println("You clicked the button");
checkOnOutputs();
}
}
);
if (y == 0) {digitalPinRadioButtonArray[x][y].setText("Input");}
if (y == 1) {digitalPinRadioButtonArray[x][y].setText("Output"); digitalPinRadioButtonArray[x][y].setSelected(true);
}
digitalPinGroupArray[x].add(digitalPinRadioButtonArray[x][y]); // assign radio buttons to group
digitalPinPanel.add(digitalPinRadioButtonArray[x][y]); // add buttons to panel
}
}
jPanel3.setBorder(javax.swing.BorderFactory.createTitledBorder("Generated Boxes"));
digitalPinOutputArray = new javax.swing.JCheckBox[digitalPinTotal];
for(int x = 0; x < digitalPinTotal ; x++) {
digitalPinOutputArray[x] = new javax.swing.JCheckBox();
digitalPinOutputArray[x].setText("Output Pin " + (x+2));
digitalPinOutputArray[x].addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e)
{
//Execute when button is pressed
createOutputChars();
}
});
jPanel3.add(digitalPinOutputArray[x]);
}
jPanel2.setBorder(javax.swing.BorderFactory.createTitledBorder("Analog Pin State"));
jProgressBar1.setMaximum(1024);
jProgressBar1.setToolTipText("");
jProgressBar1.setString(Integer.toString(jProgressBar1.getValue()));
jProgressBar1.setStringPainted(true);
jProgressBar2.setMaximum(1024);
jProgressBar2.setString(Integer.toString(jProgressBar2.getValue()));
jProgressBar2.setStringPainted(true);
jProgressBar3.setMaximum(1024);
jProgressBar3.setString(Integer.toString(jProgressBar3.getValue()));
jProgressBar3.setStringPainted(true);
jProgressBar4.setMaximum(1024);
jProgressBar4.setString(Integer.toString(jProgressBar4.getValue()));
jProgressBar4.setStringPainted(true);
jProgressBar5.setMaximum(1024);
jProgressBar5.setString(Integer.toString(jProgressBar5.getValue()));
jProgressBar5.setStringPainted(true);
jProgressBar6.setMaximum(1024);
jProgressBar6.setString(Integer.toString(jProgressBar6.getValue()));
jProgressBar6.setStringPainted(true);
jLabel1.setText("Pin A0");
jLabel2.setText("Pin A1");
jLabel3.setText("Pin A6");
jLabel4.setText("Pin A7");
jLabel5.setText("Pin A3");
jLabel6.setText("Pin A2");
jLabel7.setText("Pin A4");
jLabel8.setText("Pin A5");
jProgressBar7.setMaximum(1024);
jProgressBar7.setToolTipText("");
jProgressBar7.setString(Integer.toString(jProgressBar7.getValue()));
jProgressBar7.setStringPainted(true);
jProgressBar8.setMaximum(1024);
jProgressBar8.setToolTipText("");
jProgressBar8.setString(Integer.toString(jProgressBar8.getValue()));
jProgressBar8.setStringPainted(true);
javax.swing.GroupLayout jPanel2Layout = new javax.swing.GroupLayout(jPanel2);
jPanel2.setLayout(jPanel2Layout);
jPanel2Layout.setHorizontalGroup(
jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(jPanel2Layout.createSequentialGroup()
.addContainerGap()
.addGroup(jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(jPanel2Layout.createSequentialGroup()
.addGroup(jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jLabel7)
.addComponent(jProgressBar1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jProgressBar5, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jProgressBar6, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jLabel1)
.addComponent(jLabel2)
.addComponent(jProgressBar2, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jLabel8)
.addComponent(jLabel5)
.addComponent(jLabel3)
.addComponent(jProgressBar7, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jProgressBar3, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addContainerGap(18, Short.MAX_VALUE))
.addGroup(jPanel2Layout.createSequentialGroup()
.addGroup(jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jLabel6)
.addComponent(jProgressBar4, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jLabel4)
.addComponent(jProgressBar8, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGap(0, 0, Short.MAX_VALUE))))
);
jPanel2Layout.setVerticalGroup(
jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(jPanel2Layout.createSequentialGroup()
.addContainerGap()
.addComponent(jLabel1)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jProgressBar1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(4, 4, 4)
.addComponent(jLabel2)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jProgressBar2, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jLabel6)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
.addComponent(jProgressBar3, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jLabel5)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jProgressBar4, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jLabel7)
.addGap(9, 9, 9)
.addComponent(jProgressBar5, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jLabel8)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jProgressBar6, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jLabel3)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jProgressBar7, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jLabel4)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jProgressBar8, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addContainerGap(65, Short.MAX_VALUE))
);
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addContainerGap()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
.addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(jPanel3, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
.addGap(18, 18, 18)
.addComponent(digitalPinPanel, javax.swing.GroupLayout.PREFERRED_SIZE, 159, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jPanel2, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addContainerGap(306, Short.MAX_VALUE))
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
.addGroup(layout.createSequentialGroup()
.addGap(23, 23, 23)
.addComponent(jPanel3, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addGap(18, 18, 18)
.addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGroup(javax.swing.GroupLayout.Alignment.LEADING, layout.createSequentialGroup()
.addContainerGap()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(digitalPinPanel, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(jPanel2, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))))
.addContainerGap())
);
digitalPinPanel.getAccessibleContext().setAccessibleName("");
pack();
}// </editor-fold>
private void digitalPinPanelMouseReleased(java.awt.event.MouseEvent evt) {
}
private void checkOnOutputs() {
// if output selected enable checkbox otherwise disable it
for (int x = 0; x < digitalPinTotal; x++) {
if (digitalPinRadioButtonArray[x][0].isSelected() == true) {
digitalPinOutputArray[x].setEnabled(false);
}
if (digitalPinRadioButtonArray[x][1].isSelected() == true) {
digitalPinOutputArray[x].setEnabled(true);
}
}
}
/**
* @param args the command line arguments
*/
public static void main(String args[]) {
/* Set the Nimbus look and feel */
//<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
/* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
* For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html
*/
try {
for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
if ("Windows".equals(info.getName())) {
javax.swing.UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (ClassNotFoundException ex) {
java.util.logging.Logger.getLogger(ArduinoGUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(ArduinoGUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(ArduinoGUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(ArduinoGUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
//</editor-fold>
/* Create and display the form */
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new ArduinoGUI().setVisible(true);
}
});
}
// Variables declaration - do not modify
private javax.swing.ButtonGroup buttonGroup1;
private javax.swing.JPanel digitalPinPanel;
private javax.swing.JLabel jLabel1;
private javax.swing.JLabel jLabel2;
private javax.swing.JLabel jLabel3;
private javax.swing.JLabel jLabel4;
private javax.swing.JLabel jLabel5;
private javax.swing.JLabel jLabel6;
private javax.swing.JLabel jLabel7;
private javax.swing.JLabel jLabel8;
private javax.swing.JPanel jPanel1;
private javax.swing.JPanel jPanel2;
private javax.swing.JPanel jPanel3;
private javax.swing.JProgressBar jProgressBar1;
private javax.swing.JProgressBar jProgressBar2;
private javax.swing.JProgressBar jProgressBar3;
private javax.swing.JProgressBar jProgressBar4;
private javax.swing.JProgressBar jProgressBar5;
private javax.swing.JProgressBar jProgressBar6;
private javax.swing.JProgressBar jProgressBar7;
private javax.swing.JProgressBar jProgressBar8;
// End of variables declaration
private int digitalPinTotal = 12;
private int analogPinTotal = 8;
private javax.swing.JCheckBox[] digitalPinOutputArray;
private javax.swing.JRadioButton[][] digitalPinRadioButtonArray;
private javax.swing.ButtonGroup[] digitalPinGroupArray;
private javax.swing.JLabel[] digitalPinLabelArray;
private void initCustomComponents() {
//throw new UnsupportedOperationException("Not yet implemented");
// create checkbox array
}
private void createOutputChars(){
byte outputByte1 = 0;
byte testByte = 1;
for (int x = 0;x < 8;x++){
if (digitalPinOutputArray[x].isSelected()) {
outputByte1 += (byte) (testByte);
}
testByte = (byte) (testByte << 1);
}
printByteArray(outputByte1);
}
private void printByteArray(int inputByte) {
// print out 1 or 0
byte comparison = 0x1;
for (int x = 0;x < 8;x++)
{
if ((inputByte & comparison) > 0) {
System.out.print("1");
}
else {System.out.print("0");}
comparison = (byte) (comparison << 1);
}
System.out.println();
}
}
2 个解决方案
解决方案1
3 已采纳 2013-03-13 16:15:56
简单地忽略java字节已签名的事实。 它只会对一些操作产生影响（最值得注意的是关系运算符，如>）。
按位运算符（|，＆，^）提供与字节无符号时相同的位模式结果。
我只将要控制的位数存储到组合框中并设置/读取这样的位：
public static boolean isBitSet(byte b, int bitNo) {
return (b & (1 << bitNo) != 0;
}
public static byte setBit(byte b, int bitNo) {
return (byte) (b | (1 << bitNo));
}
public static byte clearBit(byte b, int bitNo) {
return (byte) (b & (~(1 << bitNo)));
}
虽然直接将C代码移植到java通常会由于缺少无符号类型而导致不同的行为，但差异并不是那么大。 所有无符号类型都可以用有符号类型替换，它只需要一些注意力（和知识），因为某些操作需要以不同的方式表达。
顺便说一句：没有人能够耐心地挖掘由UI构建者生成的代码墙。 如果您有特定问题，请提供简短示例，最佳可编译和可执行文件。
解决方案2
0 2013-03-13 16:43:55
将字节用作8位值时没有符号位。 当您将字节用作数字时，它只是一个符号位。 这是一个例子：
public class LearnByte
{
public static void main(final String[] arguments)
{
byte hootBerry;
hootBerry = 0x10;
System.out.printf("0x%x\t%d\n", hootBerry, hootBerry);
hootBerry |= 0x81;
System.out.printf("0x%x\t%d\n", hootBerry, hootBerry);
}
}
是否有一个通过2或3检查数字的可分性的有点技巧？
[英]Is there a bit-wise trick for checking the divisibility of a number by 2 or 3?
为什么逐位移位会在Python和Java中返回不同的结果？
[英]Why does bit-wise shift left return different results in Python and Java?
有没有办法让python产生与java相同的按位左移的结果？
[英]Is there a way making python produce the same result bit-wise shift left with java?
包含按位AND（＆）或按位异或OR（^）的运算是否具有十进制等效项？
[英]Do operations that contain bit-wise AND (&) or bit-wise exclusive OR(^) have a decimal equivalent?
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