本文目录一览：
- [Java 习题](#Java 习题)
- [JAVA 练习题](#JAVA 练习题)
- java练习题求完整代码
- java习题
Java 习题
b jdk自带工具箱中的javac.exe文件用于编译满足java编程规范的.java文件 c 第2题问的有问题，编译完成后生成的应该是文件，而不是程序，生成的文件名应该根据所编译的文件内的类的命名决定，因此这道题目没法回答，不过行业内的规范是一个java文件中只定义一个公共类，也就是和文件名一样的类，所以实在要选就只能选C了 b jdk自带工具箱中的java.exe文件用于解释执行满足java编程规范的并且编译完成的.class文件 d applet小应用程序的执行方式就是appletviewer 网页格式文件，根据题设只能选d b 所有的java文件编译完成后将生成对应类名定义的字节码文件，该文件不依附与任何操作平台，只要java虚拟机可以运行，都可以正常的执行。 b JDK Java开发工具包,Java Development Kit 里面有运行环境JRE和开发时所需要的Java类库，以及一些编译调试运行的程序，如java.exe,javac.exe,javaw.exe等。
JAVA 练习题
public class JavaExos {
public static void charInt(String chaine){ //1044
String[] charInt = new String[2];
int count = -1;
char maxChar = 'A';
int[] letterCount = new int[26];
String word = chaine.toLowerCase();
for (int i=0; i < word.length(); i++) {
int indexOfChar = (byte)word.charAt(i)-97;
letterCount[indexOfChar]++;
if (letterCount[indexOfChar] > count || (letterCount[indexOfChar] == count && word.charAt(i) < maxChar)){
count = letterCount[indexOfChar];
maxChar = word.charAt(i);
}
}
charInt[0] = String.valueOf(maxChar);
charInt[1] = ""+count;
System.out.println(charInt[0]+" "+charInt[1]);
}
public static void getDate(int n){ //1047 这题如果给1,其实是指2000年1月2号.
n++;
int[] getYear = getYear(n);
int year = getYear[0];
int[] getMonth = getMonth(year,getYear[1]);
int month = getMonth[0];
String monthString ;
if(month < 10) monthString = "0"+String.valueOf(month);
else monthString = String.valueOf(month);
int day = getMonth[1];
System.out.println(year+"-"+monthString+"-"+day+" "+getDayOfWeek(n));
}
private static boolean isBissextile(int n){
if (n%4 == 0 && !(n%100 == 0 && n%400 != 0))
return true;
else
return false;
}
private static int[] getYear(int n){
int[] getYear = new int[2];
int year = 2000;
while(n > 0){
if(isBissextile(year)) n -= 366;
else n -= 365;
if (n > 0) year++;
}
if(isBissextile(year)) n += 366;
else n += 365;
getYear[0] = year;
getYear[1] = n;
return getYear;
}
private static int[] getMonth(int year, int n){
int[] getMonth = new int[2];
int month = 1;
while(n > 0){
if(month <= 7 && month % 2 != 0) n -= 31;
else if (month == 2 && isBissextile(year) ) n -= 29;
else if (month == 2 && !isBissextile(year)) n -= 28;
else if(month <= 7 && month % 2 == 0) n -= 30;
else if(month % 2 == 0) n -= 31;
else n -= 30;
if (n > 0) month++;
}
if(month <= 7 && month % 2 != 0) n += 31;
else if (isBissextile(year) && month == 2) n += 29;
else if (!isBissextile(year) && month == 2) n += 28;
else if(month <= 7 && month % 2 == 0) n += 30;
else if(month % 2 == 0) n += 31;
else n += 30;
getMonth[0] = month;
getMonth[1] = n;
return getMonth;
}
private static String getDayOfWeek(int n){
int quotient = n / 7;
int remainder = n -= quotient * 7;
switch(remainder){
case 0 : return "Sunday";
case 1 : return "Monday";
case 2 : return "Tuesday";
case 3 : return "Wednesday";
case 4 : return "Thursday";
case 5 : return "Friday";
case 6 : return "Saturday";
default : return "Never arrive";
}
}
public static void getCode(String chaine){ //1048
chaine = chaine.toUpperCase();
System.out.println("START");
System.out.println(chaine);
System.out.println("END");
System.out.println();
for(int i=0; i < chaine.length(); i++){
System.out.print((changChar(chaine.charAt(i))));
}
System.out.println();
}
private static char changChar(char c){
if(c >= 65 && c <= 90 && c - 5 < 65) return (char)(c + 26 - 5);
else if(c >= 65 && c <= 90) return (char)(c - 5);
else return c;
}
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
JavaExos.charInt("adfadffasdfda");
JavaExos.getDate(1751);
JavaExos.getCode("NS BFW, JAJSYX TK NRUTWYFSHJ FWJ YMJ WJXZQY TK YWNANFQ HFZXJX");
}
}
java练习题求完整代码
按照题目要求编写的用javaBean规范设计的学生类Student的Java程序如下 需要创建user.java.test包,把Student.java文件和Test.java文件放入包中,编译Student.java文件并且编译运行Test.java文件得到运行结果 Student.java文件代码如下
package user.java.test;
import java.io.Serializable;
public class Student implements Serializable{
private static final long serialVersionUID = 1L;
private String no;
private String name;
private double score;
public Student(){}
public Student(String no,String name,double score){
this.no=no;
this.name=name;
this.score=score;
}
public String getNo(){ return no;}
public void setNo(String no){ this.no=no;}
public String getName(){ return name;}
public void setName(String name){ this.name=name;}
public double getScore(){ return score;}
public void setScore(double score){ this.score=score;}
public String toString(){
return "学号:"+no+",姓名:"+name+",成绩:"+score;
}
public static double getAvg(Student[] sArray){
double sum=0,avg;
for(int i=0; i < sArray.length; i++){
sum=sum+sArray[i].getScore();
}
avg=sum/sArray.length;
return avg;
}
}
Test.java文件代码如下
package user.java.test;
public class Test{
public static void main(String[] args){
Student[] sArray=new Student[5];
sArray[0]=new Student("001","张三",89.5);
sArray[1]=new Student("002","李四",82.5);
sArray[2]=new Student("003","王五",93);
sArray[3]=new Student("004","赵六",73.5);
sArray[4]=new Student("005","孙七",66);
System.out.println("这些学生的平均分:"+Student.getAvg(sArray));
for(int i=0; i < sArray.length; i++){
System.out.println(sArray[i].toString());
}
}
}
java习题
import javax.swing.*;
import javax.swing.event.*;
import java.awt.*;
import java.awt.event.*;
public class calculator extends JFrame implements ActionListener {
JFrame frame;
private JButton jia = new JButton("+");
private JButton jian = new JButton("-");
private JButton cheng = new JButton("*");
private JButton chu = new JButton("/");
private JButton qiuyi = new JButton("%");
private JButton deng = new JButton("=");
private JButton fu = new JButton("+/-");
private JButton dian = new JButton(".");
private JButton kai = new JButton("sqrt");
private JButton diao = new JButton("1/x");
private JButton aa = new JButton("A");
private JButton bb = new JButton("B");
private JButton cc = new JButton("C");
private JButton dd = new JButton("D");
private JButton ee = new JButton("E");
private JButton ff = new JButton("F");
private TextField k1 = new TextField();
private objConversion convert = new objConversion();
JMenuItem copy, paste, s, t, help, about, me;
JRadioButton sixteen, ten, eight, two;
JButton backspace, ce, c, num0, num1, num2, num3, num4, num5, num6, num7, num8, num9;
Container cp;
JTextField text;
String copycontent = "";
boolean clickable = true, clear = true;
int all = 0;
double qian;
String fuhao;
int jin = 10, first = 1;
public calculator() {
setTitle("计算器－杨彩制作");
setSize(400, 300);
setLocation(250, 200);
text = new JTextField(25);
text.setText("0.");
text.setHorizontalAlignment(JTextField.RIGHT); //从右到左
JPanel cp1 = new JPanel();
JPanel cp2 = new JPanel();
JPanel cp3 = new JPanel();
cp = getContentPane();
cp.add(cp1, "North");
cp.add(cp2, "Center");
cp.add(cp3, "South");
cp1.setLayout(new GridLayout(1, 6));
cp2.setLayout(new GridLayout(2, 4));
cp3.setLayout(new GridLayout(6, 6));
sixteen = new JRadioButton("十六进制");
sixteen.setVisible(false);
ten = new JRadioButton("十进制", true);
ten.setVisible(false);
eight = new JRadioButton("八进制");
eight.setVisible(false);
two = new JRadioButton("二进制");
two.setVisible(false);
sixteen.addActionListener(this);
ten.addActionListener(this);
eight.addActionListener(this);
two.addActionListener(this);
ButtonGroup btg = new ButtonGroup();
btg.add(sixteen);
btg.add(ten);
btg.add(eight);
btg.add(two);
JTextField t3 = new JTextField(25);
cp1.add(text);
text.setEditable(false);
text.setBackground(new Color(255, 255, 255));
cp2.add(sixteen);
cp2.add(ten);
cp2.add(eight);
cp2.add(two);
backspace = new JButton("Backspace");
backspace.setForeground(new Color(255, 0, 0));
backspace.addActionListener(this);
ce = new JButton("CE");
ce.setForeground(new Color(255, 0, 0));
ce.addActionListener(this);
c = new JButton("C");
c.setForeground(new Color(255, 0, 0));
c.addActionListener(this);
k1.setVisible(false);
cp2.add(k1);
cp2.add(backspace);
cp2.add(ce);
cp2.add(c);
num0 = new JButton("0");
num1 = new JButton("1");
num2 = new JButton("2");
num3 = new JButton("3");
num4 = new JButton("4");
num5 = new JButton("5");
num6 = new JButton("6");
num7 = new JButton("7");
num8 = new JButton("8");
num9 = new JButton("9");
cp3.add(num7);
num7.addActionListener(this);
cp3.add(num8);
num8.addActionListener(this);
cp3.add(num9);
num9.addActionListener(this);
cp3.add(chu);
chu.setForeground(new Color(255, 0, 0));
chu.addActionListener(this);
cp3.add(kai);
kai.addActionListener(this);
cp3.add(num4);
num4.addActionListener(this);
cp3.add(num5);
num5.addActionListener(this);
cp3.add(num6);
num6.addActionListener(this);
cp3.add(cheng);
cheng.setForeground(new Color(255, 0, 0));
cheng.addActionListener(this);
cp3.add(qiuyi);
qiuyi.addActionListener(this);
cp3.add(num1);
num1.addActionListener(this);
cp3.add(num2);
num2.addActionListener(this);
cp3.add(num3);
num3.addActionListener(this);
cp3.add(jian);
jian.setForeground(new Color(255, 0, 0));
jian.addActionListener(this);
cp3.add(diao);
diao.addActionListener(this);
cp3.add(num0);
num0.addActionListener(this);
cp3.add(fu);
fu.addActionListener(this);
cp3.add(dian);
dian.addActionListener(this);
cp3.add(jia);
jia.setForeground(new Color(255, 0, 0));
jia.addActionListener(this);
cp3.add(deng);
deng.setForeground(new Color(255, 0, 0));
deng.addActionListener(this);
cp3.add(aa);
aa.addActionListener(this);
cp3.add(bb);
bb.addActionListener(this);
cp3.add(cc);
cc.addActionListener(this);
cp3.add(dd);
dd.addActionListener(this);
cp3.add(ee);
ee.addActionListener(this);
cp3.add(ff);
ff.addActionListener(this);
aa.setVisible(false);
bb.setVisible(false);
cc.setVisible(false);
dd.setVisible(false);
ee.setVisible(false);
ff.setVisible(false);
JMenuBar mainMenu = new JMenuBar();
setJMenuBar(mainMenu);
JMenu editMenu = new JMenu("编辑");
JMenu viewMenu = new JMenu("查看");
JMenu helpMenu = new JMenu("帮助");
mainMenu.add(editMenu);
mainMenu.add(viewMenu);
mainMenu.add(helpMenu);
copy = new JMenuItem(" 复制");
paste = new JMenuItem(" 粘贴");
KeyStroke copyks = KeyStroke.getKeyStroke(KeyEvent.VK_C, Event.CTRL_MASK);
copy.setAccelerator(copyks); //设置退出菜单选项加上快捷键
KeyStroke pasteks = KeyStroke.getKeyStroke(KeyEvent.VK_V, Event.CTRL_MASK);
paste.setAccelerator(pasteks); //设置退出菜单选项加上快捷键
editMenu.add(copy);
editMenu.add(paste);
copy.addActionListener(this);
paste.addActionListener(this);
t = new JMenuItem("●标准型");
s = new JMenuItem(" 科学型");
viewMenu.add(t);
viewMenu.add(s);
t.addActionListener(this);
s.addActionListener(this);
help = new JMenuItem(" 帮助主题");
about = new JMenuItem(" 关于计算器");
me = new JMenuItem(" 作者主页");
helpMenu.add(help);
helpMenu.add(about);
helpMenu.add(me);
help.addActionListener(this);
about.addActionListener(this);
me.addActionListener(this);
addWindowListener(new WindowDestroyer()); //结束窗口
}
public void actionPerformed(ActionEvent e) { //响应动作代码
if(first == 1)
text.setText("");
first = 0; //第一次把文本框0.清空
Object temp = e.getSource();
if(temp == copy) {
copycontent = text.getText();
}
if(temp == paste) {
text.setText(text.getText() + copycontent);
}
if(temp == t) { //标准
sixteen.setVisible(false);
ten.setVisible(false);
eight.setVisible(false);
two.setVisible(false);
t.setText("●标准型");
s.setText(" 科学型");
aa.setVisible(false);
bb.setVisible(false);
cc.setVisible(false);
dd.setVisible(false);
ee.setVisible(false);
ff.setVisible(false);
}
if(temp == s) { //科学
sixteen.setVisible(true);
ten.setVisible(true);
eight.setVisible(true);
two.setVisible(true);
t.setText(" 标准型");
s.setText("●科学型");
aa.setVisible(true);
bb.setVisible(true);
cc.setVisible(true);
dd.setVisible(true);
ee.setVisible(true);
ff.setVisible(true);
aa.setEnabled(false);
bb.setEnabled(false);
cc.setEnabled(false);
dd.setEnabled(false);
ee.setEnabled(false);
ff.setEnabled(false);
}
if(temp == help) { //打开系统帮助文件 要查资料
try {
String filePath = "C:/WINDOWS/Help/calc.chm";
Runtime.getRuntime().exec("cmd.exe /c " + filePath);
} catch(Exception eeee) {
System.out.println("打开系统的计算器出错");
}
}
if(temp == about) {
JOptionPane.showMessageDialog(frame, " Java计算器\n 杨彩 制作\n\n ", "关于计算器", JOptionPane.INFORMATION_MESSAGE);
}
if(temp == me) {
try {
Process p = Runtime.getRuntime().exec("explorer ");
} catch(Exception eeee) {
System.out.println("打开指定网页出错");
}
}
try {
if(temp == sixteen) {
String hex = text.getText();
int inthex = Integer.parseInt(hex, jin); //先把数变为10进制
text.setText(convert.decHex(inthex));
jin = 16;
aa.setEnabled(true);
bb.setEnabled(true);
cc.setEnabled(true);
dd.setEnabled(true);
ee.setEnabled(true);
ff.setEnabled(true);
num2.setEnabled(true);
num3.setEnabled(true);
num4.setEnabled(true);
num5.setEnabled(true);
num6.setEnabled(true);
num7.setEnabled(true);
num8.setEnabled(true);
num9.setEnabled(true);
}
if(temp == eight) {
String oct = text.getText();
int intoct = Integer.parseInt(oct, jin);
text.setText(convert.decOct(intoct));
jin = 8;
aa.setEnabled(false);
bb.setEnabled(false);
cc.setEnabled(false);
dd.setEnabled(false);
ee.setEnabled(false);
ff.setEnabled(false);
num2.setEnabled(true);
num3.setEnabled(true);
num4.setEnabled(true);
num5.setEnabled(true);
num6.setEnabled(true);
num7.setEnabled(true);
num8.setEnabled(false);
num9.setEnabled(false);
}
if(temp == two) {
String bin = text.getText();
int intbin = Integer.parseInt(bin, jin);
text.setText(convert.decBin(intbin));
jin = 2;
aa.setEnabled(false);
bb.setEnabled(false);
cc.setEnabled(false);
dd.setEnabled(false);
ee.setEnabled(false);
ff.setEnabled(false);
num2.setEnabled(false);
num3.setEnabled(false);
num4.setEnabled(false);
num5.setEnabled(false);
num6.setEnabled(false);
num7.setEnabled(false);
num8.setEnabled(false);
num9.setEnabled(false);
}
if(temp == ten) {
String dec = text.getText();
int intdec = Integer.parseInt(dec, jin);
text.setText(intdec + "");
jin = 10;
aa.setEnabled(false);
bb.setEnabled(false);
cc.setEnabled(false);
dd.setEnabled(false);
ee.setEnabled(false);
ff.setEnabled(false);
num2.setEnabled(true);
num3.setEnabled(true);
num4.setEnabled(true);
num5.setEnabled(true);
num6.setEnabled(true);
num7.setEnabled(true);
num8.setEnabled(true);
num9.setEnabled(true);
}
} catch(Exception ee) {
System.out.println("转换出错,可能你没有输入任何字符");
text.setText("转换出错");
clear = false;
}
if(temp == backspace) { //退格
String s = text.getText();
text.setText("");
for (int i = 0; i < s.length() - 1; i++) {
char a = s.charAt(i);
text.setText(text.getText() + a);
}
}
if (temp == ce) {
text.setText("0.");
clear = true;
first = 1;
}
if (temp == c) {
text.setText("0.");
clear = true;
first = 1;
}
if(temp == num0) {
if(clear == false) //判断是否点击了符号位
text.setText("");
text.setText(text.getText() + "0");
}
if(temp == num1) {
if(clear == false)
text.setText("");
text.setText(text.getText() + "1");
clear = true; //第二次不在清空（前二句）
}
if(temp == num2) {
if(clear == false)
text.setText("");
text.setText(text.getText() + "2");
clear = true;
}
if(temp == num3) {
if(clear == false)
text.setText("");
text.setText(text.getText() + "3");
clear = true;
}
if(temp == num4) {
if(clear == false)
text.setText("");
text.setText(text.getText() + "4");
clear = true;
}
if(temp == num5) {
if(clear == false)
text.setText("");
text.setText(text.getText() + "5");
clear = true;
}
if(temp == num6) {
if(clear == false)
text.setText("");
text.setText(text.getText() + "6");
clear = true;
}
if(temp == num7) {
if(clear == false)
text.setText("");
text.setText(text.getText() + "7");
clear = true;
}
if(temp == num8) {
if(clear == false)
text.setText("");
text.setText(text.getText() + "8");
clear = true;
}
if(temp == num9) {
if(clear == false)
text.setText("");
text.setText(text.getText() + "9");
clear = true;
}
if(temp == aa) {
text.setText(text.getText() + "A");
}
if(temp == bb) {
text.setText(text.getText() + "B");
}
if(temp == cc) {
text.setText(text.getText() + "C");
}
if(temp == dd) {
text.setText(text.getText() + "D");
}
if(temp == ee) {
text.setText(text.getText() + "E");
}
if(temp == ff) {
text.setText(text.getText() + "F");
}
if(temp == dian) {
clickable = true;
for (int i = 0; i < text.getText().length(); i++)
if ('.' == text.getText().charAt(i)) {
clickable = false;
break;
} //第一层判断是否里面含有小数点;
if(clickable == true) //第二坛判断
text.setText(text.getText() + ".");
}
try {
if(temp == jia) { //加法
qian = Double.parseDouble(text.getText());
fuhao = "+";
clear = false;
}
if(temp == jian) {
qian = Double.parseDouble(text.getText());
fuhao = "-";
clear = false;
}
if(temp == cheng) {
qian = Double.parseDouble(text.getText());
fuhao = "*";
clear = false;
}
if(temp == chu) {
qian = Double.parseDouble(text.getText());
fuhao = "/";
clear = false;
}
if(temp == deng) {
double ss = Double.parseDouble(text.getText());
text.setText("");
if(fuhao.equals("+"))
text.setText(qian + ss + "");
if(fuhao.equals("-"))
text.setText(qian - ss + "");
if(fuhao.equals("*"))
text.setText(qian * ss + "");
if(fuhao.equals("/"))
text.setText(qian / ss + "");
clear = false; //要清空前一次的数据
}
if(temp == kai) {
String s = text.getText();
if (s.charAt(0) == '-') {
text.setText("负数不能开根号");
} else
text.setText(Double.toString(java.lang.Math.sqrt(Double.parseDouble(text.getText()))));
clear = false;
}
if(temp == diao) {
if (text.getText().charAt(0) == '0' && text.getText().length() == 1) {
text.setText("除数不能为零");
} else {
boolean isDec = true;
int i, j, k;
String s = Double.toString(1 / Double.parseDouble(text.getText()));
for (i = 0; i < s.length(); i++)
if (s.charAt(i) == '.')
break;
for (j = i + 1; j < s.length(); j++)
if (s.charAt(j) != '0') {
isDec = false;
break;
}
if (isDec == true) {
String stemp = "";
for (k = 0; k < i; k++)
stemp += s.charAt(k);
text.setText(stemp);
} else
text.setText(s);
}
clear = false;
}
if(temp == qiuyi) {
text.setText("0");
clear = false;
}
if (temp == fu) { //导师，此方法参考书中例子
boolean isNumber = true;
String s = text.getText();
for (int i = 0; i < s.length(); i++)
if (! (s.charAt(i) >= '0' && s.charAt(i) <= '9' || s.charAt(i) == '.' || s.charAt(i) == '-')) {
isNumber = false;
break;
}
if (isNumber == true) {
//如果当前字符串首字母有'-'号,代表现在是个负数,再按下时,则将首符号去掉
if (s.charAt(0) == '-') {
text.setText("");
for (int i = 1; i < s.length(); i++) {
char a = s.charAt(i);
text.setText(text.getText() + a);
}
} //如果当前字符串第一个字符不是符号，则添加一个符号在首字母处
else
text.setText('-' + s);
}
}
} catch(Exception eee) {
System.out.println("运算时,首先输入数字或字符");
text.setText("运算出错");
clear = false;
}
}
class WindowDestroyer extends WindowAdapter { //退出窗口动作
public void windowClosing(WindowEvent e) {
System.exit(0);
}
}
class objConversion { //导师,本进制类参考了CSMD类转换例子
public void objConversion () {}
public String decDec (int decNum) { //10
String strDecNum = Integer.toString(decNum);
for (int i = strDecNum.length(); i < 3; i++) {
strDecNum = "0" + strDecNum;
}
return invert (strDecNum, 5);
}
public String decHex (int decNum) { //10 to 16
String strHexNum = "";
int currentNum = 0;
while (decNum != 0) {
if (decNum > 15) {
currentNum = decNum % 16;
decNum /= 16;
} else {
currentNum = decNum;
decNum = 0;
}
switch (currentNum) {
case 15: strHexNum += "F"; break;
case 14: strHexNum += "E"; break;
case 13: strHexNum += "D"; break;
case 12: strHexNum += "C"; break;
case 11: strHexNum += "B"; break;
case 10: strHexNum += "A"; break;
default: strHexNum += Integer.toString(currentNum); break;
}
}
return invert (strHexNum, 2);
}
public String decOct (int decNum) { //10 to 8
String strOctNum = "";
while (decNum != 0) {
if (decNum > 7) {
strOctNum += Integer.toString(decNum % 8);
decNum /= 8;
} else {
strOctNum += Integer.toString(decNum);
decNum = 0;
}
}
return invert (strOctNum, 3);
}
public String decBin (int decNum) { //10 to 2
String strBinNum = "";
while (decNum != 0) {
if (decNum > 1) {
strBinNum += Integer.toString(decNum % 2);
decNum /= 2;
} else {
strBinNum += Integer.toString(decNum);
decNum = 0;
}
}
return invert (strBinNum, 8);
}
private String invert (String strNum, int minLength) { //转换长度
String answer = "";
int length = strNum.length();
if (length < minLength) {
for (int padding = (minLength - length); padding > 0; padding--) {
answer += "0";
}
}
for (int i = length; i > 0; i--) {
answer += strNum.charAt (i - 1);
}
return answer;
}
}
public static void main(String arg[]) { //产生窗口
calculator win = new calculator();
win.setVisible(true);
}
}
第二个:
