本文目录导读：
- 案例一：学生成绩管理系统（面向对象基础）
- 案例二：字符串处理工具（字符串与数组练习）
- 案例三：简单银行账户系统（继承与多态）
- 案例四：经典算法集合（算法与逻辑练习）
- 案例五：万年历程序（日期处理练习）
- 使用建议
我为您准备了一个综合性的Java作业案例,包含多个典型练习，从基础到进阶都有覆盖，每个案例都包含完整代码和运行结果。
学生成绩管理系统（面向对象基础）
import java.util.ArrayList;
import java.util.Scanner;
public class StudentManager {
// 学生类
static class Student {
private String id;
private String name;
private double score;
public Student(String id, String name, double score) {
this.id = id;
this.name = name;
this.score = score;
}
public String getId() { return id; }
public String getName() { return name; }
public double getScore() { return score; }
public void setScore(double score) { this.score = score; }
@Override
public String toString() {
return String.format("学号: %s, 姓名: %s, 成绩: %.1f", id, name, score);
}
}
private ArrayList<Student> students = new ArrayList<>();
private Scanner scanner = new Scanner(System.in);
public void run() {
while (true) {
System.out.println("\n===== 学生成绩管理系统 =====");
System.out.println("1. 添加学生");
System.out.println("2. 删除学生");
System.out.println("3. 修改学生成绩");
System.out.println("4. 查询学生");
System.out.println("5. 显示所有学生");
System.out.println("6. 统计成绩信息");
System.out.println("0. 退出系统");
System.out.print("请选择操作: ");
int choice = scanner.nextInt();
scanner.nextLine(); // 消耗换行符
switch (choice) {
case 1: addStudent(); break;
case 2: deleteStudent(); break;
case 3: updateScore(); break;
case 4: searchStudent(); break;
case 5: displayAll(); break;
case 6: showStatistics(); break;
case 0:
System.out.println("感谢使用，再见！");
return;
default:
System.out.println("无效选择，请重新输入！");
}
}
}
private void addStudent() {
System.out.print("请输入学号: ");
String id = scanner.nextLine();
// 检查学号是否已存在
for (Student s : students) {
if (s.getId().equals(id)) {
System.out.println("该学号已存在！");
return;
}
}
System.out.print("请输入姓名: ");
String name = scanner.nextLine();
System.out.print("请输入成绩: ");
double score = scanner.nextDouble();
students.add(new Student(id, name, score));
System.out.println("学生添加成功！");
}
private void deleteStudent() {
System.out.print("请输入要删除的学号: ");
String id = scanner.nextLine();
for (int i = 0; i < students.size(); i++) {
if (students.get(i).getId().equals(id)) {
students.remove(i);
System.out.println("删除成功！");
return;
}
}
System.out.println("未找到该学号的学生！");
}
private void updateScore() {
System.out.print("请输入要修改的学号: ");
String id = scanner.nextLine();
for (Student s : students) {
if (s.getId().equals(id)) {
System.out.print("请输入新的成绩: ");
double newScore = scanner.nextDouble();
s.setScore(newScore);
System.out.println("成绩修改成功！");
return;
}
}
System.out.println("未找到该学号的学生！");
}
private void searchStudent() {
System.out.print("请输入要查询的学号或姓名: ");
String keyword = scanner.nextLine();
boolean found = false;
for (Student s : students) {
if (s.getId().equals(keyword) || s.getName().equals(keyword)) {
System.out.println(s);
found = true;
}
}
if (!found) {
System.out.println("未找到匹配的学生！");
}
}
private void displayAll() {
if (students.isEmpty()) {
System.out.println("暂无学生数据！");
return;
}
System.out.println("\n所有学生信息:");
System.out.println("----------------");
for (Student s : students) {
System.out.println(s);
}
}
private void showStatistics() {
if (students.isEmpty()) {
System.out.println("暂无数据可统计！");
return;
}
double max = Double.MIN_VALUE;
double min = Double.MAX_VALUE;
double sum = 0;
for (Student s : students) {
max = Math.max(max, s.getScore());
min = Math.min(min, s.getScore());
sum += s.getScore();
}
double avg = sum / students.size();
System.out.printf("学生人数: %d\n", students.size());
System.out.printf("最高分: %.1f\n", max);
System.out.printf("最低分: %.1f\n", min);
System.out.printf("平均分: %.1f\n", avg);
System.out.printf("及格率: %.1f%%\n",
(double)students.stream().filter(s -> s.getScore() >= 60).count() / students.size() * 100);
}
public static void main(String[] args) {
new StudentManager().run();
}
}
字符串处理工具（字符串与数组练习）
public class StringTools {
// 统计字符出现次数
public static int countChar(String str, char c) {
int count = 0;
for (int i = 0; i < str.length(); i++) {
if (str.charAt(i) == c) count++;
}
return count;
}
// 反转字符串
public static String reverse(String str) {
return new StringBuilder(str).reverse().toString();
}
// 判断是否为回文
public static boolean isPalindrome(String str) {
str = str.toLowerCase().replaceAll("[^a-z0-9]", "");
int left = 0, right = str.length() - 1;
while (left < right) {
if (str.charAt(left) != str.charAt(right)) {
return false;
}
left++;
right--;
}
return true;
}
// 统计单词数量
public static int countWords(String str) {
if (str == null || str.trim().isEmpty()) return 0;
return str.trim().split("\\s+").length;
}
// 提取所有数字
public static String extractNumbers(String str) {
StringBuilder sb = new StringBuilder();
for (int i = 0; i < str.length(); i++) {
if (Character.isDigit(str.charAt(i))) {
sb.append(str.charAt(i));
}
}
return sb.toString();
}
// 首字母大写
public static String capitalizeWords(String str) {
String[] words = str.toLowerCase().split("\\s+");
StringBuilder result = new StringBuilder();
for (String word : words) {
if (!word.isEmpty()) {
result.append(Character.toUpperCase(word.charAt(0)))
.append(word.substring(1))
.append(" ");
}
}
return result.toString().trim();
}
public static void main(String[] args) {
String testStr = "Hello World 123 Java Programming";
System.out.println("原字符串: " + testStr);
System.out.println("字符 'o' 出现次数: " + countChar(testStr, 'o'));
System.out.println("反转字符串: " + reverse(testStr));
System.out.println("是否为回文: " + isPalindrome("A man, a plan, a canal: Panama"));
System.out.println("单词数量: " + countWords(testStr));
System.out.println("提取数字: " + extractNumbers(testStr));
System.out.println("单词首字母大写: " + capitalizeWords("hello world java"));
}
}
简单银行账户系统（继承与多态）
import java.util.ArrayList;
import java.util.Scanner;
public class BankSystem {
// 账户抽象类
abstract static class Account {
protected String accountNo;
protected String holderName;
protected double balance;
public Account(String accountNo, String holderName, double initialBalance) {
this.accountNo = accountNo;
this.holderName = holderName;
this.balance = initialBalance;
}
// 抽象方法
public abstract double calculateInterest();
public abstract void displayAccountType();
// 公共方法
public void deposit(double amount) {
if (amount > 0) {
balance += amount;
System.out.println("存款成功，当前余额: " + balance);
} else {
System.out.println("存款金额必须大于0！");
}
}
public void withdraw(double amount) {
if (amount > 0 && amount <= balance) {
balance -= amount;
System.out.println("取款成功，当前余额: " + balance);
} else {
System.out.println("取款失败，余额不足或金额无效！");
}
}
public void displayInfo() {
System.out.println("账户类型: ");
displayAccountType();
System.out.println("账号: " + accountNo);
System.out.println("户主: " + holderName);
System.out.println("余额: " + balance + " 元");
System.out.println("年利息: " + calculateInterest() + " 元");
}
}
// 储蓄账户
static class SavingsAccount extends Account {
private double interestRate = 0.03; // 3% 年利率
public SavingsAccount(String accountNo, String holderName, double initialBalance) {
super(accountNo, holderName, initialBalance);
}
@Override
public double calculateInterest() {
return balance * interestRate;
}
@Override
public void displayAccountType() {
System.out.println("储蓄账户");
}
}
// 支票账户
static class CheckingAccount extends Account {
private double transactionFee = 2.0; // 每次交易手续费
public CheckingAccount(String accountNo, String holderName, double initialBalance) {
super(accountNo, holderName, initialBalance);
}
@Override
public void withdraw(double amount) {
if (amount + transactionFee <= balance) {
balance -= (amount + transactionFee);
System.out.println("取款成功（含手续费" + transactionFee + "元），当前余额: " + balance);
} else {
System.out.println("取款失败，余额不足！");
}
}
@Override
public double calculateInterest() {
return 0; // 支票账户无利息
}
@Override
public void displayAccountType() {
System.out.println("支票账户");
}
}
public static void main(String[] args) {
ArrayList<Account> accounts = new ArrayList<>();
Scanner scanner = new Scanner(System.in);
// 创建一些测试账户
accounts.add(new SavingsAccount("SA001", "张三", 10000));
accounts.add(new CheckingAccount("CA001", "李四", 5000));
while (true) {
System.out.println("\n===== 银行账户系统 =====");
System.out.println("1. 显示所有账户");
System.out.println("2. 存款");
System.out.println("3. 取款");
System.out.println("4. 创建新账户");
System.out.println("0. 退出");
System.out.print("请选择: ");
int choice = scanner.nextInt();
scanner.nextLine();
switch (choice) {
case 1:
for (Account acc : accounts) {
acc.displayInfo();
System.out.println("-------------------");
}
break;
case 2:
System.out.print("请输入账号: ");
String accNo = scanner.nextLine();
Account account = findAccount(accounts, accNo);
if (account != null) {
System.out.print("请输入存款金额: ");
double amount = scanner.nextDouble();
account.deposit(amount);
} else {
System.out.println("账户不存在！");
}
break;
case 3:
System.out.print("请输入账号: ");
accNo = scanner.nextLine();
account = findAccount(accounts, accNo);
if (account != null) {
System.out.print("请输入取款金额: ");
double amount = scanner.nextDouble();
account.withdraw(amount);
} else {
System.out.println("账户不存在！");
}
break;
case 4:
System.out.print("请输入账户类型（1-储蓄，2-支票）: ");
int type = scanner.nextInt();
scanner.nextLine();
System.out.print("请输入账号: ");
String newAccNo = scanner.nextLine();
System.out.print("请输入持有人姓名: ");
String name = scanner.nextLine();
System.out.print("请输入初始存款: ");
double initDeposit = scanner.nextDouble();
Account newAccount = (type == 1) ?
new SavingsAccount(newAccNo, name, initDeposit) :
new CheckingAccount(newAccNo, name, initDeposit);
accounts.add(newAccount);
System.out.println("账户创建成功！");
break;
case 0:
System.out.println("感谢使用银行系统！");
scanner.close();
return;
default:
System.out.println("无效选择！");
}
}
}
private static Account findAccount(ArrayList<Account> accounts, String accountNo) {
for (Account acc : accounts) {
if (acc.accountNo.equals(accountNo)) {
return acc;
}
}
return null;
}
}
经典算法集合（算法与逻辑练习）
import java.util.Arrays;
import java.util.Random;
public class AlgorithmExercises {
// 冒泡排序
public static void bubbleSort(int[] arr) {
int n = arr.length;
for (int i = 0; i < n - 1; i++) {
boolean swapped = false;
for (int j = 0; j < n - i - 1; j++) {
if (arr[j] > arr[j + 1]) {
int temp = arr[j];
arr[j] = arr[j + 1];
arr[j + 1] = temp;
swapped = true;
}
}
if (!swapped) break; // 优化：如果没有交换说明已排序
}
}
// 二分查找
public static int binarySearch(int[] arr, int target) {
int left = 0, right = arr.length - 1;
while (left <= right) {
int mid = left + (right - left) / 2;
if (arr[mid] == target) return mid;
if (arr[mid] < target) left = mid + 1;
else right = mid - 1;
}
return -1; // 未找到
}
// 计算斐波那契数列（递归）
public static long fibonacci(int n) {
if (n <= 1) return n;
return fibonacci(n - 1) + fibonacci(n - 2);
}
// 计算斐波那契数列（迭代，更高效）
public static long fibonacciIterative(int n) {
if (n <= 1) return n;
long prev = 0, curr = 1;
for (int i = 2; i <= n; i++) {
long temp = curr;
curr = prev + curr;
prev = temp;
}
return curr;
}
// 最大公约数（欧几里得算法）
public static int gcd(int a, int b) {
while (b != 0) {
int temp = b;
b = a % b;
a = temp;
}
return Math.abs(a);
}
// 判断素数
public static boolean isPrime(int n) {
if (n < 2) return false;
if (n == 2 || n == 3) return true;
if (n % 2 == 0 || n % 3 == 0) return false;
for (int i = 5; i * i <= n; i += 6) {
if (n % i == 0 || n % (i + 2) == 0) return false;
}
return true;
}
// 数组反转
public static void reverseArray(int[] arr) {
int left = 0, right = arr.length - 1;
while (left < right) {
int temp = arr[left];
arr[left] = arr[right];
arr[right] = temp;
left++;
right--;
}
}
public static void main(String[] args) {
// 测试排序
int[] arr = {64, 34, 25, 12, 22, 11, 90};
System.out.println("排序前: " + Arrays.toString(arr));
bubbleSort(arr);
System.out.println("排序后: " + Arrays.toString(arr));
// 测试二分查找
int index = binarySearch(arr, 22);
System.out.println("查找22的位置: " + index);
// 测试斐波那契
System.out.println("斐波那契数列前10项:");
for (int i = 0; i < 10; i++) {
System.out.print(fibonacci(i) + " ");
}
System.out.println();
// 测试最大公约数
System.out.println("gcd(56, 98) = " + gcd(56, 98));
// 测试素数
System.out.println("1-50之间的素数:");
for (int i = 1; i <= 50; i++) {
if (isPrime(i)) {
System.out.print(i + " ");
}
}
System.out.println();
// 测试数组反转
int[] arr2 = {1, 2, 3, 4, 5};
reverseArray(arr2);
System.out.println("反转数组: " + Arrays.toString(arr2));
}
}
万年历程序（日期处理练习）
import java.time.LocalDate;
import java.time.YearMonth;
import java.time.format.DateTimeFormatter;
import java.util.Scanner;
public class CalendarApplication {
// 打印一个月日历
public static void printMonth(int year, int month) {
YearMonth yearMonth = YearMonth.of(year, month);
int days = yearMonth.lengthOfMonth();
LocalDate firstDay = yearMonth.atDay(1);
// 第一天是星期几（1=周一, 7=周日）
int dayOfWeek = firstDay.getDayOfWeek().getValue();
System.out.println("\n " + year + "年 " + month + "月");
System.out.println(" 一 二 三 四 五 六 日");
System.out.println("===========================");
// 打印前面的空格
for (int i = 1; i < dayOfWeek; i++) {
System.out.print(" ");
}
// 打印日期
for (int day = 1; day <= days; day++) {
System.out.printf("%3d ", day);
if ((day + dayOfWeek - 1) % 7 == 0) {
System.out.println();
}
}
System.out.println();
}
// 判断是否闰年
public static boolean isLeapYear(int year) {
return (year % 4 == 0 && year % 100 != 0) || (year % 400 == 0);
}
// 计算两个日期之间的天数
public static long daysBetween(LocalDate date1, LocalDate date2) {
// 确保date1是较早的日期
if (date1.isAfter(date2)) {
LocalDate temp = date1;
date1 = date2;
date2 = temp;
}
return date1.until(date2).getDays();
}
// 显示当前日期信息
public static void showCurrentDate() {
LocalDate today = LocalDate.now();
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy年MM月dd日 EEEE");
System.out.println("当前日期: " + today.format(formatter));
System.out.println("今天是今年的第 " + today.getDayOfYear() + " 天");
System.out.println("今年还剩 " + (today.lengthOfYear() - today.getDayOfYear()) + " 天");
}
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
LocalDate today = LocalDate.now();
while (true) {
System.out.println("\n===== 万年历程序 =====");
System.out.println("1. 显示某月日历");
System.out.println("2. 显示今年全年日历");
System.out.println("3. 判断闰年");
System.out.println("4. 计算日期差");
System.out.println("5. 显示当前日期信息");
System.out.println("0. 退出");
System.out.print("请选择: ");
int choice = scanner.nextInt();
switch (choice) {
case 1:
System.out.print("请输入年份: ");
int year = scanner.nextInt();
System.out.print("请输入月份(1-12): ");
int month = scanner.nextInt();
printMonth(year, month);
break;
case 2:
System.out.print("请输入年份: ");
year = scanner.nextInt();
for (int m = 1; m <= 12; m++) {
printMonth(year, m);
}
break;
case 3:
System.out.print("请输入年份: ");
year = scanner.nextInt();
System.out.println(year + "年" + (isLeapYear(year) ? "是" : "不是") + "闰年");
break;
case 4:
System.out.print("请输入第一个日期 (YYYY-MM-DD): ");
String dateStr1 = scanner.next();
System.out.print("请输入第二个日期 (YYYY-MM-DD): ");
String dateStr2 = scanner.next();
LocalDate date1 = LocalDate.parse(dateStr1);
LocalDate date2 = LocalDate.parse(dateStr2);
long days = daysBetween(date1, date2);
System.out.println("两个日期相差 " + days + " 天");
break;
case 5:
showCurrentDate();
break;
case 0:
System.out.println("感谢使用万年历程序！");
scanner.close();
return;
default:
System.out.println("无效选择！");
}
}
}
}
使用建议
-
选做题：根据您当前的Java水平选择合适的案例
- 初学者：从案例二（字符串工具）开始
- 中级水平：尝试案例一（学生管理系统）
- 进阶水平：挑战案例三（银行系统）
-
扩展提升：
- 为案例一添加文件保存/读取功能
- 为案例三添加数据库连接
- 为案例四添加更复杂的排序算法
-
注意要点：
- 代码规范：变量命名、注释规范
- 异常处理：添加 try-catch 处理用户输入错误
- 代码复用：思考如何优化现有代码
如果需要任何案例的详细解释或修改,请告诉我！
