• Java基础项目~用户管理系统

    目录

    1，整体应用操作界面

    UserApplication.java

    2，数据访问对象，用于封装数据的访问逻辑细节

     package-info.java

    接口类：IUserDao

    UserDaoImpl.java  继承于IUserDao接口

    3，定义值bean

    User.java

    4,工具类

    ArrayList.java

    DaoFactory.java

    代码运行截图：

    1，整体应用操作界面

    UserApplication.java

    1. package com.yan.app;
    2.  
    3. import java.io.BufferedReader;
    4. import java.io.IOException;
    5. import java.io.InputStreamReader;
    6.  
    7. import com.yan.dao.IUserDao;
    8. import com.yan.entity.User;
    9. import com.yan.util.DaoFactory;
    10.  
    11. public class UserApplication {
    12. 	private static User user = null;
    13.  
    14. 	public static void main(String[] args) throws Exception {
    15. 		IUserDao userDao = DaoFactory.getUserDao();
    16. 		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    17. 		while (true) {
    18. 			menu1();
    19. 			String ss = br.readLine();
    20. 			switch (ss) {
    21. 			case "1":
    22. 				User user = inputUser(br);
    23. 				userDao.save(user);
    24. 				break;
    25. 			case "2":
    26. 				User user1 = loginUser(br);
    27. 				User bb = userDao.login(user1);
    28. 				if (bb != null) {
    29. 					UserApplication.user = bb;
    30. 					System.out.println("登录成功！");
    31. 				} else {
    32. 					System.out.println("登录失败！请重新登录");
    33. 				}
    34. 				break;
    35. 			case "3":
    36. 				System.out.println("====目前已注册的用户列表====");
    37. 				Object[] arr = userDao.getAll().getArray();
    38. 				for (Object temp : arr) {
    39. 					if (temp != null)
    40. 						System.out.println(temp);
    41. 				}
    42. 				System.out.println("====================");
    43. 				break;
    44. 			case "4":
    45. 				User user2 = mofidyUser(br);
    46. 				userDao.update(user2);
    47. 				UserApplication.user = null;
    48. 				System.out.println("修改完毕！请重新登录");
    49. 				break;
    50. 			case "5":
    51. 				UserApplication.user = null;
    52. 				System.out.println("退出登录");
    53. 				break;
    54. 			case "6":
    55. 				System.out.println("输入要删除的用户编号：");
    56. 				Long id = null;
    57. 				while (true) {
    58. 					String ss1 = br.readLine();
    59. 					try {
    60. 						id = Long.parseLong(ss1);
    61. 						break;
    62. 					} catch (Exception e) {
    63. 						System.out.println("输入的数据格式错误！请重新输入");
    64. 						id = null;
    65. 					}
    66. 				}
    67. 				if (id.equals(UserApplication.user.getId()))
    68. 					UserApplication.user = null;
    69. 				userDao.delete(id);
    70. 				break;
    71.  
    72. //				default:
    73. //				System.exit(0);
    74. //				break;
    75.  
    76. 			}
    77. 			if ("0".equals(ss)) {
    78. 				System.out.println("bye~~bye");
    79. 				break;
    80. 			}
    81. 		}
    82. 		br.close();
    83. 	}
    84.  
    85. 	private static User mofidyUser(BufferedReader br) throws Exception {
    86. 		User res = UserApplication.user;
    87. 		System.out.println("请输入新的用户名称和接口和指令：");
    88. 		System.out.println("原始名称为：" + res.getUsername());
    89. 		System.out.println("请输入新的用户名称：（不修改则直接回车）");
    90. 		String username = br.readLine();
    91. 		if (username != null && username.trim().length() >= 6 && username.trim().length() <= 20)
    92. 			res.setUsername(username);
    93. 		System.out.println("请输入新用户口令：（不修改则直接回车）");
    94. 		String password = br.readLine();
    95. 		if (password != null && password.trim().length() >= 6 && password.trim().length() <= 20)
    96. 			res.setPassword(password);
    97. 		return res;
    98. 	}
    99.  
    100. 	private static User loginUser(BufferedReader br) {
    101. 		System.out.println("请输入用户名称和口令：");
    102. 		String username = inputString(br, "用户名称", 6, 20);
    103. 		String password = inputString(br, "用户口令", 6, 20);
    104. 		User user = new User();
    105. 		user.setUsername(username);
    106. 		user.setPassword(password);
    107. 		return user;
    108. 	}
    109.  
    110. 	public static void menu1() {
    111. 		System.out.println("============欢迎使用本系统============");
    112. 		System.out.println("1---新增用户            2---登录系统");
    113. 		if (user != null) {
    114. 			System.out.println("3---显示所有用户        4---修改注册信息");
    115. 			System.out.println("5---退出登录            6---删除用户");
    116. 		}
    117. 		System.out.println("0---退出系统");
    118. 		System.out.println("=================================");
    119. 		System.out.println("请选择...");
    120. 	}
    121.  
    122. 	public static User inputUser(BufferedReader br) {
    123. 		User user = new User();
    124. 		String username = inputString(br, "用户名称", 6);
    125. 		String password = null;
    126. 		while (true) {
    127. 			password = inputString(br, "用户口令", 6, 20);
    128. 			String repassword = inputString(br, "确认口令");
    129. 			if (password.equals(repassword))
    130. 				break;
    131. 			System.out.println("您输入的口令和确认口令不一致，请重新输入");
    132. 		}
    133. 		user.setUsername(username);
    134. 		user.setPassword(password);
    135. 		return user;
    136. 	}
    137.  
    138. 	// int...如果有参数，则参数1为最小长度，参数2为最大长度
    139.  
    140. 	public static String inputString(BufferedReader br, String name, int... params) {
    141. 		String res = null;
    142. 		boolean flag = false;
    143. 		while (true) {
    144. 			System.out.println("请输入" + name + ":");
    145. 			try {
    146. 				res = br.readLine();
    147. 				if (res != null) {
    148. 					if (params != null && params.length > 0) {
    149. 						flag = res.trim().length() >= params[0];
    150. 						if (flag) {
    151. 							if (params.length > 1)
    152. 								flag = res.trim().length() <= params[1];
    153. 						}
    154. 					} else
    155. 						flag = true;
    156. 				}
    157. 			} catch (IOException e) {
    158. 				e.printStackTrace();
    159. 			}
    160. 			if (flag)
    161. 				break;
    162. 			else
    163. 				System.out.println("你输入的数据有误！请重新输入");
    164. 		}
    165. 		return res;
    166. 	}
    167.  
    168. }

    2，数据访问对象，用于封装数据的访问逻辑细节

    信息系统项目管理师-信息系统项目管理基础章节考点总结思维导图
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     package-info.java

    1. class Constants {
    2. 	public static final String FILE_NAME = "data/users.data";
    3. 	public static final String TEMP_NAME = "data/users_tmp.data";
    4. }

    接口类：IUserDao

    1. package com.yan.dao;
    2.  
    3. import com.yan.entity.User;
    4. import com.yan.util.ArrayList;
    5.  
    6. public interface IUserDao {
    7. 	boolean save(User user);
    8.  
    9. 	User login(User user);
    10.  
    11. 	boolean delete(Long id);
    12.  
    13. 	boolean update(User user2);
    14.  
    15. 	ArrayList getAll();
    16.  
    17. }

    UserDaoImpl.java  继承于IUserDao接口

    1. package com.yan.dao;
    2.  
    3. import java.io.EOFException;
    4. import java.io.File;
    5. import java.io.FileInputStream;
    6. import java.io.FileOutputStream;
    7. import java.io.ObjectInputStream;
    8. import java.io.ObjectOutputStream;
    9.  
    10. import com.yan.entity.User;
    11. import com.yan.util.ArrayList;
    12. import com.yan.util.DaoFactory;
    13.  
    14. public class UserDaoImpl implements IUserDao {
    15. 	public boolean save(User user) {
    16. 		boolean res = false;
    17. 		File oldFile = new File(Constants.FILE_NAME);
    18. 		File tmpFile = new File(Constants.TEMP_NAME);
    19. //判断oIdFile是否存在。exists存在的
    20. 		if (oldFile.exists()) {
    21. 			// FileInput
    22. 			try (ObjectInputStream ois = new ObjectInputStream(new FileInputStream(oldFile));
    23. 					ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream(tmpFile));) {
    24. 				long maxId = ois.readLong();
    25. 				user.setId(maxId + 1);
    26. 				oos.writeLong(user.getId());
    27. 				while (true) {
    28. 					try {
    29. 						// read读取
    30. 						Object tmp = ois.readObject();
    31. 						if (tmp != null)
    32. 							// write写入
    33. 							oos.writeObject(tmp);
    34. 					} catch (EOFException e) {
    35. 						break;
    36. 					}
    37. 				}
    38. 				oos.writeObject(user);
    39. 				res = true;
    40. 			} catch (Exception e) {
    41. 				// 在命令行打印异常信息在程序中出错的位置及原因
    42. 				e.printStackTrace();
    43. 				res = false;
    44. 			}
    45. 		} else {
    46. 			try (ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream(oldFile));) {
    47. 				user.setId(1L);
    48. 				oos.writeLong(user.getId());
    49. 				oos.writeObject(user);
    50. 				res = true;
    51. 			} catch (Exception e) {
    52. 				e.printStackTrace();
    53. 				res = false;
    54. 			}
    55. 		}
    56. 		if (oldFile.exists() && tmpFile.exists()) {
    57. 			oldFile.delete();
    58. 			tmpFile.renameTo(oldFile);
    59. 		}
    60. 		return res;
    61.  
    62. 	}
    63.  
    64. 	public static void main(String[] args) {
    65. 		IUserDao userDao = DaoFactory.getUserDao();
    66. 		User user = new User();
    67. 		user.setId(2L);
    68. 		user.setUsername("zhangsan");
    69. 		user.setPassword("666666");
    70. 		boolean res = userDao.update(user);
    71. 		System.out.println(res ? "成功" : "失败");
    72. 	}
    73.  
    74. 	@Override
    75. 	public User login(User user1) {
    76. 		User res = null;
    77. 		File oIdFile = new File(Constants.FILE_NAME);
    78. 		if (oIdFile.exists()) {
    79. 			try (ObjectInputStream ois = new ObjectInputStream(new FileInputStream(oIdFile))) {
    80. 				ois.skip(8);
    81. 				while (true) {
    82. 					Object obj = ois.readObject();
    83. 					if (obj != null && obj instanceof User) {
    84. 						User tmp = (User) obj;
    85. 						if (user1.equals(tmp)) {
    86. 							res = tmp;
    87. 							break;
    88. 						}
    89. 					}
    90. 				}
    91. 			} catch (EOFException e) {
    92. 				System.out.println("文件结束...");
    93. 			} catch (Exception e) {
    94. 				e.printStackTrace();
    95. 			}
    96. 		}
    97. 		return res;
    98. 	}
    99.  
    100. 	@Override
    101. 	public ArrayList getAll() {
    102. 		ArrayList res = new ArrayList();
    103. 		File oldFile = new File(Constants.FILE_NAME);
    104. 		if (oldFile.exists()) {
    105. 			try (ObjectInputStream ois = new ObjectInputStream(new FileInputStream(oldFile))) {
    106. 				ois.skip(8);
    107. 				while (true) {
    108. 					Object obj = ois.readObject();
    109. 					res.add(obj);
    110. 				}
    111. 			} catch (EOFException e) {
    112. 				System.out.println("数据加载完毕!");
    113. 			} catch (Exception e) {
    114. 				e.printStackTrace();
    115. 			}
    116. 		}
    117. 		return res;
    118. 	}
    119.  
    120. 	@Override
    121. 	public boolean update(User user) {
    122. 		boolean res = false;
    123. 		File oldFile = new File(Constants.FILE_NAME);
    124. 		File tmpFile = new File(Constants.TEMP_NAME);
    125. 		if (oldFile.exists()) {
    126. 			try (ObjectInputStream ois = new ObjectInputStream(new FileInputStream(oldFile));
    127. 					ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream(tmpFile));) {
    128. 				oos.writeLong(ois.readLong());
    129. 				while (true) {
    130. 					try {
    131. 						Object tmp = ois.readObject();
    132. 						System.out.println(user);
    133. 						if (tmp != null) {
    134. 							if (!tmp.equals(user)) {
    135. 								System.out.println(tmp);
    136. 								oos.writeObject(tmp);
    137. 							} else {
    138. 								oos.writeObject(user);
    139. 								res = true;
    140. 							}
    141. 						}
    142. 					} catch (EOFException e) {
    143. 						break;
    144. 					}
    145. 				}
    146. 			} catch (Exception e) {
    147. 				e.printStackTrace();
    148. 				res = false;
    149. 			}
    150. 		}
    151. 		if (oldFile.exists() && tmpFile.exists()) {
    152. 			oldFile.delete();
    153. 			tmpFile.renameTo(oldFile);
    154. 		}
    155. 		return res;
    156. 	}
    157.  
    158. 	@Override
    159. 	public boolean delete(Long id) {
    160. 		boolean res = false;
    161. 		File oldFile = new File(Constants.FILE_NAME);
    162. 		File tmpFile = new File(Constants.TEMP_NAME);
    163. 		if (oldFile.exists()) {
    164. 			try (ObjectInputStream ois = new ObjectInputStream(new FileInputStream(oldFile));
    165. 					ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream(tmpFile));) {
    166. 				oos.writeLong(ois.readLong());
    167. 				while (true) {
    168. 					try {
    169. 						Object tmp = ois.readObject();
    170. 						if (tmp != null) {
    171. 							if (tmp instanceof User) {
    172. 								User temp = (User) tmp;
    173. 								if (!id.equals(temp.getId())) {
    174. 									oos.writeObject(tmp);
    175. 								} else {
    176. 									res = true;
    177. 								}
    178. 							}
    179. 						}
    180. 					} catch (EOFException e) {
    181. 						break;
    182. 					}
    183. 				}
    184. 			} catch (Exception e) {
    185. 				e.printStackTrace();
    186. 				res = false;
    187. 			}
    188. 		}
    189. 		if (oldFile.exists() && tmpFile.exists()) {
    190. 			oldFile.delete();
    191. 			tmpFile.renameTo(oldFile);
    192. 		}
    193. 		return res;
    194.  
    195. 	}
    196.  
    197. }

    3，定义值bean

    User.java

    1. package com.yan.entity;
    2.  
    3. import java.io.Serializable;
    4. import java.util.Objects;
    5.  
    6. public class User implements Serializable {
    7. 	/**
    8. 	 * 
    9. 	 */
    10. 	private static final long serialVersionUID = 1L;
    11. 	private Long id;
    12. 	private String username;
    13. 	private String password;
    14. 	private String repassword;
    15.  
    16. 	@Override
    17. 	public int hashCode() {
    18. 		if (this.id == null)
    19. 			return Objects.hash(password, username);
    20. 		return Objects.hash(id);
    21. 	}
    22.  
    23. 	@Override
    24. 	public boolean equals(Object obj) {
    25. 		if (this == obj)
    26. 			return true;
    27. 		if (obj == null)
    28. 			return false;
    29. 		if (getClass() != obj.getClass())
    30. 			return false;
    31. 		User other = (User) obj;
    32. 		if (this.id == null || other.id == null)
    33. 			return Objects.equals(password, other.password) && Objects.equals(username, other.username);
    34. 		else
    35. 			return Objects.equals(this.id, other.id);
    36. 	}
    37.  
    38. 	// =============================
    39. 	public Long getId() {
    40. 		return id;
    41. 	}
    42.  
    43. 	public void setId(Long id) {
    44. 		this.id = id;
    45. 	}
    46.  
    47. 	public String getUsername() {
    48. 		return username;
    49. 	}
    50.  
    51. 	public void setUsername(String username) {
    52. 		this.username = username;
    53. 	}
    54.  
    55. 	public String getPassword() {
    56. 		return password;
    57. 	}
    58.  
    59. 	public String getShowPassword() {
    60. 		StringBuilder sb = new StringBuilder();
    61. 		for (int i = 0; i < password.length(); i++)
    62. 			sb.append("*");
    63. 		return sb.toString();
    64. 	}
    65.  
    66. 	public void setPassword(String password) {
    67. 		this.password = password;
    68. 	}
    69.  
    70. 	public String getRepassword() {
    71. 		return repassword;
    72. 	}
    73.  
    74. 	public void setRepassword(String repassword) {
    75. 		this.repassword = repassword;
    76. 	}
    77.  
    78. 	@Override
    79. 	public String toString() {
    80. 		return "User [id=" + id + ", username=" + username + ", password=" + this.getShowPassword() + "]";
    81. 	}
    82.  
    83. }

    4,工具类

    ArrayList.java

    1. package com.yan.util;
    2.  
    3. public class ArrayList {
    4. 	private Object[] arr;
    5. 	private int count;
    6.  
    7. 	public ArrayList() {
    8. 		this(10);
    9.  
    10. 	}
    11.  
    12. 	public ArrayList(int length) {
    13. 		arr = new Object[length];
    14. 	}
    15.  
    16. 	public void add(Object obj) {
    17. 		arr[count++] = obj;
    18. 		if (count >= arr.length) {
    19. 			resize();
    20. 		}
    21. 	}
    22.  
    23. 	public Object[] getArray() {
    24. 		return arr;
    25. 	}
    26.  
    27. 	private void resize() {
    28. 		Object[] res = new Object[arr.length * 2];
    29. 		System.arraycopy(arr, 0, res, 0, arr.length);
    30. 		this.arr = res;
    31. 	}
    32. }
    33.

    DaoFactory.java

    1. package com.yan.util;
    2.  
    3. import com.yan.dao.IUserDao;
    4. import com.yan.dao.UserDaoImpl;
    5.  
    6. public class DaoFactory {
    7. 	private DaoFactory() {
    8.  
    9. 	}
    10.  
    11. 	private static IUserDao userDao = new UserDaoImpl();
    12.  
    13. 	public static IUserDao getUserDao() {
    14. 		return userDao;
    15. 	}
    16.  
    17. }

    代码运行截图：

     

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  • 原文地址：https://blog.csdn.net/qq_51222096/article/details/126321328