a

src/client/Client.java

@@ -79,10 +79,10 @@ public class Client {
 					update();
 					break;
 				case 6:
-					ExportToCSV.to();
+					ExportToCSV.to("output.csv", "select * from book");
 					break;
 				case 7:
-					ExportToXLS.to();
+					ExportToXLS.to("select * from book", "output.xls");
 					break;
 				default:
 					break;

src/server/Server.java

@@ -6,14 +6,18 @@ import java.net.Socket;
 import server.thread.HandleThread;
 
 public class Server {
-	public static void main(String[] args) throws Exception {
-		int port = 9999;
-		ServerSocket server = new ServerSocket(port);
-		System.out.println("The server is listening for client connection requests on port " + port + ".");
-		while (true) {
-			Socket socket = server.accept();
-			System.out.println("Client " + socket.getInetAddress().getHostAddress() + " successfully connected!");
-			new HandleThread(socket).start();
+	private static final int PORT = 9999;
+
+	public static void main(String[] args) {
+		try (ServerSocket server = new ServerSocket(PORT)) {
+			System.out.println("Server listening on port " + PORT);
+			while (true) {
+				Socket clientSocket = server.accept();
+				System.out.println("Client connected: " + clientSocket.getInetAddress().getHostAddress());
+				new Thread(new HandleThread(clientSocket)).start();
+			}
+		} catch (Exception e) {
+			System.err.println("Server exception: " + e.getMessage());
 		}
 	}
 }

src/server/dao/UserDAO.java

@@ -10,38 +10,36 @@ import server.vo.User;
 
 public class UserDAO {
 	public static User get(String userName) throws Exception {
-		User user = null;
-		Connection con = DBConnection.getConnection();
-		String sql = "select * from user where userName=?";
-		PreparedStatement pst = con.prepareStatement(sql);
-		pst.setString(1, userName);
-		ResultSet rs = pst.executeQuery();
-		while (rs.next()) {
-			user = new User();
-			user.setUserName(rs.getString("userName"));
-			user.setPassword(rs.getString("password"));
-			user.setName(rs.getString("name"));
-			user.setRole(rs.getString("role"));
+		String sql = "SELECT * FROM user WHERE userName=?";
+		try (Connection con = DBConnection.getConnection();
+				PreparedStatement pst = con.prepareStatement(sql)) {
+			pst.setString(1, userName);
+			try (ResultSet rs = pst.executeQuery()) {
+				if (rs.next())
+					return createUserFromResultSet(rs);
+			}
 		}
-		DBConnection.close(con, pst);
-		return user;
+		return null;
 	}
 
 	public static ArrayList<User> query(User userCondition) throws Exception {
-		ArrayList<User> list = new ArrayList<User>();
-		Connection con = DBConnection.getConnection();
-		String sql = "*******";
-		PreparedStatement pst = con.prepareStatement(sql);
-		ResultSet rs = pst.executeQuery();
-		while (rs.next()) {
-			User user = new User();
-			user.setUserName(rs.getString("userName"));
-			user.setPassword(rs.getString("password"));
-			user.setName(rs.getString("name"));
-			user.setRole(rs.getString("role"));
-			list.add(user);
+		ArrayList<User> list = new ArrayList<>();
+		String sql = "SELECT * FROM user"; // 示例SQL，实际应根据userCondition调整
+		try (Connection con = DBConnection.getConnection();
+				PreparedStatement pst = con.prepareStatement(sql);
+				ResultSet rs = pst.executeQuery()) {
+			while (rs.next())
+				list.add(createUserFromResultSet(rs));
 		}
-		DBConnection.close(con, pst);
 		return list;
 	}
+
+	private static User createUserFromResultSet(ResultSet rs) throws Exception {
+		User user = new User();
+		user.setUserName(rs.getString("userName"));
+		user.setPassword(rs.getString("password"));
+		user.setName(rs.getString("name"));
+		user.setRole(rs.getString("role"));
+		return user;
+	}
 }

src/server/thread/HandleThread.java

@@ -1,9 +1,7 @@
 package server.thread;
 
 import java.io.BufferedReader;
-import java.io.InputStream;
 import java.io.InputStreamReader;
-import java.io.OutputStream;
 import java.io.OutputStreamWriter;
 import java.io.PrintWriter;
 import java.net.Socket;
@@ -11,98 +9,81 @@ import java.util.HashMap;
 import java.util.Map;
 
 import com.google.gson.Gson;
-import com.google.gson.JsonElement;
 import com.google.gson.JsonObject;
-import com.google.gson.JsonParser;
 
 import server.dao.UserDAO;
 import server.vo.User;
 
 public class HandleThread extends Thread {
 	private Socket socket;
-	private BufferedReader buf;
-	private PrintWriter write;
 
 	public HandleThread(Socket socket) {
-		super();
 		this.socket = socket;
-		try {
-			InputStream is = socket.getInputStream();
-			buf = new BufferedReader(new InputStreamReader(is, "utf-8"));
-			OutputStream os = socket.getOutputStream();
-			write = new PrintWriter(new OutputStreamWriter(os, "utf-8"));
-		} catch (Exception e) {
-			e.printStackTrace();
-		}
 	}
 
 	@Override
 	public void run() {
-		while (true) {
-			try {
-				String receiveStr = buf.readLine();
+		try (BufferedReader buf = new BufferedReader(new InputStreamReader(socket.getInputStream(), "utf-8"));
+				PrintWriter write = new PrintWriter(new OutputStreamWriter(socket.getOutputStream(), "utf-8"))) {
+			String receiveStr;
+			while ((receiveStr = buf.readLine()) != null) {
 				System.out.println("Receive the client's request data: " + receiveStr);
-				JsonElement element = JsonParser.parseString(receiveStr);
-				JsonObject obj = element.getAsJsonObject();
+				JsonObject obj = new Gson().fromJson(receiveStr, JsonObject.class);
 				int code = obj.get("code").getAsInt();
-				if (code == 8) {
-					close();
+				if (code == 8)
 					break;
-				}
 				String data = obj.get("data").getAsString();
-				String response = "";
-				switch (code) {
-					case 0:
-						response = loginHandle(data);
-						break;
-					case 1:
-						break;
-					case 2:
-						break;
-					default:
-						System.out.println("Invalid command!");
-						break;
-				}
+				String response = handleRequest(code, data);
 				write.println(response);
 				write.flush();
-			} catch (Exception e) {
-				e.printStackTrace();
 			}
+		} catch (Exception e) {
+			e.printStackTrace();
+		} finally {
+			System.out.println("Client exited!");
+			closeResources();
 		}
-		System.out.println("Client exited!");
 	}
 
-	public void close() throws Exception {
-		if (write != null)
-			write.close();
-		if (buf != null)
-			buf.close();
-		if (socket != null)
-			socket.close();
+	private String handleRequest(int code, String data) throws Exception {
+		switch (code) {
+			case 0:
+				return loginHandle(data);
+			case 1:
+				// Handle other cases
+				return "";
+			case 2:
+				// Handle other cases
+				return "";
+			default:
+				System.out.println("Invalid command!");
+				return "";
+		}
 	}
 
-	public String loginHandle(String str) throws Exception {
+	private String loginHandle(String str) throws Exception {
 		User loginUser = new Gson().fromJson(str, User.class);
 		User user = UserDAO.get(loginUser.getUserName());
-		String responseData = "";
+		Map<String, Object> map = new HashMap<>();
 		if (user == null) {
-			Map<String, Object> map = new HashMap<>();
 			map.put("code", 0);
 			map.put("data", "Username does not exist!");
-			responseData = new Gson().toJson(map);
+		} else if (loginUser.getPassword().equals(user.getPassword())) {
+			map.put("code", 1);
+			map.put("data", new Gson().toJson(user));
 		} else {
-			if (loginUser.getPassword().equals(user.getPassword())) {
-				Map<String, Object> map = new HashMap<>();
-				map.put("code", 1);
-				map.put("data", new Gson().toJson(user));
-				responseData = new Gson().toJson(map);
-			} else {
-				Map<String, Object> map = new HashMap<>();
-				map.put("code", 0);
-				map.put("data", "Wrong password!");
-				responseData = new Gson().toJson(map);
-			}
+			map.put("code", 0);
+			map.put("data", "Wrong password!");
 		}
-		return responseData;
+		return new Gson().toJson(map);
 	}
-}
+
+	private void closeResources() {
+		try {
+			if (socket != null)
+				socket.close();
+		} catch (Exception e) {
+			e.printStackTrace();
+		}
+	}
+}

src/server/tools/DBConnection.java

@@ -2,7 +2,6 @@ package server.tools;
 
 import java.sql.Connection;
 import java.sql.DriverManager;
-import java.sql.PreparedStatement;
 import java.sql.SQLException;
 
 public class DBConnection {
@@ -10,32 +9,32 @@ public class DBConnection {
 	private final static String url = "jdbc:mysql://localhost:3306/lda?allowPublicKeyRetrieval=true&useSSL=false";
 	private final static String user = "root";
 	private final static String password = "516849";
+
 	static {
 		try {
 			Class.forName(driverName);
-		} catch (Exception e) {
-			e.printStackTrace();
+		} catch (ClassNotFoundException e) {
+			throw new ExceptionInInitializerError(e);
 		}
 	}
 
 	public static Connection getConnection() {
-		Connection connection = null;
 		try {
-			connection = DriverManager.getConnection(url, user, password);
+			return DriverManager.getConnection(url, user, password);
 		} catch (SQLException e) {
-			e.printStackTrace();
+			throw new RuntimeException("Failed to get database connection", e);
 		}
-		return connection;
 	}
 
-	public static void close(Connection con, PreparedStatement pst) {
-		try {
-			if (pst != null)
-				pst.close();
-			if (con != null)
-				con.close();
-		} catch (SQLException e) {
-			e.printStackTrace();
+	public static void close(AutoCloseable... resources) {
+		for (AutoCloseable resource : resources) {
+			if (resource != null) {
+				try {
+					resource.close();
+				} catch (Exception e) {
+					e.printStackTrace();
+				}
+			}
 		}
 	}
 }

src/server/tools/ExportToCSV.java

@@ -8,29 +8,36 @@ import java.sql.SQLException;
 import java.sql.Statement;
 
 public class ExportToCSV {
-    public static void to() {
-        String outputFile = "Library Data.csv";
+    public static void to(String outputFile, String query) {
         try (Connection connection = DBConnection.getConnection();
                 Statement statement = connection.createStatement();
-                ResultSet resultSet = statement.executeQuery("SELECT * FROM book");
+                ResultSet resultSet = statement.executeQuery(query);
                 FileWriter fileWriter = new FileWriter(outputFile)) {
-            for (int i = 1; i <= resultSet.getMetaData().getColumnCount(); i++) {
-                fileWriter.append(resultSet.getMetaData().getColumnName(i));
-                if (i < resultSet.getMetaData().getColumnCount())
-                    fileWriter.append(",");
-            }
-            fileWriter.append("\n");
-            while (resultSet.next()) {
-                for (int i = 1; i <= resultSet.getMetaData().getColumnCount(); i++) {
-                    fileWriter.append(resultSet.getString(i));
-                    if (i < resultSet.getMetaData().getColumnCount())
-                        fileWriter.append(",");
-                }
-                fileWriter.append("\n");
-            }
-            System.out.println("Data exported successfully!");
+            writeColumnNames(resultSet, fileWriter);
+            writeDataRows(resultSet, fileWriter);
+            System.out.println("Data exported successfully to " + outputFile);
         } catch (SQLException | IOException e) {
             e.printStackTrace();
         }
     }
-}
+
+    private static void writeColumnNames(ResultSet resultSet, FileWriter fileWriter) throws SQLException, IOException {
+        for (int i = 1; i <= resultSet.getMetaData().getColumnCount(); i++) {
+            fileWriter.append(resultSet.getMetaData().getColumnName(i));
+            if (i < resultSet.getMetaData().getColumnCount())
+                fileWriter.append(",");
+        }
+        fileWriter.append("\n");
+    }
+
+    private static void writeDataRows(ResultSet resultSet, FileWriter fileWriter) throws SQLException, IOException {
+        while (resultSet.next()) {
+            for (int i = 1; i <= resultSet.getMetaData().getColumnCount(); i++) {
+                fileWriter.append(resultSet.getString(i));
+                if (i < resultSet.getMetaData().getColumnCount())
+                    fileWriter.append(",");
+            }
+            fileWriter.append("\n");
+        }
+    }
+}

src/server/tools/ExportToXLS.java

@@ -11,37 +11,38 @@ import jxl.write.WritableSheet;
 import jxl.write.WritableWorkbook;
 
 public class ExportToXLS {
-    public static void to() {
+    public static void to(String query, String outputPath) {
+        String[] columnHeaders = { "title", "author", "publisher", "oldprice", "newprice", "href" };
         try (Connection connection = DBConnection.getConnection();
                 Statement statement = connection.createStatement();
-                ResultSet rs = statement.executeQuery("SELECT * FROM book");) {
-            WritableWorkbook book = Workbook.createWorkbook(new File("Library Data.xls"));
-            WritableSheet sheet = book.createSheet("sheet1", 0);
-            Label label = new Label(0, 0, "title");
-            sheet.addCell(label);
-            label = new Label(1, 0, "author");
-            sheet.addCell(label);
-            label = new Label(2, 0, "publisher");
-            sheet.addCell(label);
-            label = new Label(3, 0, "oldprice");
-            sheet.addCell(label);
-            label = new Label(4, 0, "newprice");
-            sheet.addCell(label);
-            label = new Label(5, 0, "href");
-            sheet.addCell(label);
-            int i = 1;
-            while (rs.next()) {
-                for (int j = 0; j <= 5; j++) {
-                    label = new Label(j, i, rs.getString(j + 1));
-                    sheet.addCell(label);
-                }
-                i++;
-            }
-            book.write();
-            book.close();
-            System.out.println("Data exported successfully!");
+                ResultSet rs = statement.executeQuery(query)) {
+            WritableWorkbook workbook = Workbook.createWorkbook(new File(outputPath));
+            WritableSheet sheet = workbook.createSheet("Sheet1", 0);
+            createColumnHeaders(sheet, columnHeaders);
+            writeDataRows(sheet, rs);
+            workbook.write();
+            workbook.close();
+            System.out.println("Data exported successfully to " + outputPath);
         } catch (Exception e) {
             e.printStackTrace();
         }
     }
+
+    private static void createColumnHeaders(WritableSheet sheet, String[] columnHeaders) throws Exception {
+        for (int i = 0; i < columnHeaders.length; i++) {
+            Label label = new Label(i, 0, columnHeaders[i]);
+            sheet.addCell(label);
+        }
+    }
+
+    private static void writeDataRows(WritableSheet sheet, ResultSet rs) throws Exception {
+        int rowIndex = 1;
+        while (rs.next()) {
+            for (int columnIndex = 0; columnIndex <= 5; columnIndex++) {
+                Label label = new Label(columnIndex, rowIndex, rs.getString(columnIndex + 1));
+                sheet.addCell(label);
+            }
+            rowIndex++;
+        }
+    }
 }

src/server/tools/crawling/Book.java

@@ -69,6 +69,7 @@ public class Book {
     }
 
     public String toString() {
-        return "Title: " + this.title + ", Author: " + this.author + ", Publisher: " + this.publisher + ", Original Price: " + this.oldprice + ", Discounted Price: " + this.newprice + ", URL: " + this.href;
+        return "Title: " + this.title + ", Author: " + this.author + ", Publisher: " + this.publisher
+                + ", Original Price: " + this.oldprice + ", Discounted Price: " + this.newprice + ", URL: " + this.href;
     }
 }

src/server/tools/crawling/CrawlerTools.java

@@ -2,9 +2,7 @@ package server.tools.crawling;
 
 import java.io.BufferedReader;
 import java.io.IOException;
-import java.io.InputStream;
 import java.io.InputStreamReader;
-import java.io.UnsupportedEncodingException;
 import java.net.HttpURLConnection;
 import java.net.URL;
 import java.net.URLEncoder;
@@ -12,43 +10,22 @@ import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
 public class CrawlerTools {
-	public static String get(String urlStr, String charset) {
-		StringBuffer buf = new StringBuffer();
-		HttpURLConnection con = null;
-		InputStream in = null;
-		BufferedReader read = null;
-		try {
-			URL url = new URL(urlStr);
-			con = (HttpURLConnection) url.openConnection();
-			con.setRequestProperty("User-Agent",
-					"Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/101.0.4951.64 Safari/537.36 Edg/101.0.1210.53");
-			int code = con.getResponseCode();
-			if (code == 200) {
-				in = con.getInputStream();
-				read = new BufferedReader(new InputStreamReader(in, charset));
-				String info = "";
+	public static String get(String urlStr, String charset) throws IOException {
+		StringBuilder buf = new StringBuilder();
+		URL url = new URL(urlStr);
+		HttpURLConnection con = (HttpURLConnection) url.openConnection();
+		con.setRequestProperty("User-Agent",
+				"Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/101.0.4951.64 Safari/537.36 Edg/101.0.1210.53");
+		if (con.getResponseCode() == 200) {
+			try (BufferedReader read = new BufferedReader(new InputStreamReader(con.getInputStream(), charset))) {
+				String info;
 				while ((info = read.readLine()) != null)
 					buf.append(info);
-			} else
-				System.out.println("Error! Response code: " + code + ".");
-		} catch (Exception e) {
-			e.printStackTrace();
-		} finally {
-			if (read != null)
-				try {
-					read.close();
-				} catch (IOException e) {
-					e.printStackTrace();
-				}
-			if (in != null)
-				try {
-					in.close();
-				} catch (IOException e) {
-					e.printStackTrace();
-				}
-			if (con != null)
-				con.disconnect();
+			}
+		} else {
+			System.out.println("Error! Response code: " + con.getResponseCode() + ".");
 		}
+		con.disconnect();
 		return buf.toString();
 	}
 
@@ -58,15 +35,12 @@ public class CrawlerTools {
 		Matcher mat = pat.matcher(url);
 		while (mat.find()) {
 			String hanzi = mat.group();
-			System.out.println(hanzi);
-			String encodehanzi = "";
 			try {
-				encodehanzi = URLEncoder.encode(hanzi, "utf-8");
-			} catch (UnsupportedEncodingException e) {
+				url = url.replace(hanzi, URLEncoder.encode(hanzi, "utf-8"));
+			} catch (IOException e) {
 				e.printStackTrace();
 			}
-			url = url.replaceAll(hanzi, encodehanzi);
 		}
 		return url;
 	}
-}
+}

src/server/tools/crawling/Driver.java

@@ -1,19 +1,32 @@
 package server.tools.crawling;
 
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.TimeUnit;
+
 public class Driver {
+    private static final String URL_PREFIX = "http://bang.dangdang.com/books/bestsellers/01.00.00.00.00.00-24hours-0-0-1-";
+
     public static void crawl() {
+        ExecutorService executor = Executors.newFixedThreadPool(5);
         try {
-            String url = "http://bang.dangdang.com/books/bestsellers/01.00.00.00.00.00-24hours-0-0-1-1";
-            Thread thread1 = new Thread(new NewsThread(url));
-            thread1.start();
-            for (int i = 2; i <= 5; i++) {
-                String url2 = "http://bang.dangdang.com/books/bestsellers/01.00.00.00.00.00-24hours-0-0-1-" + i;
-                Thread thread2 = new Thread(new NewsThread(url2));
-                thread2.start();
-                Thread.sleep(10000);
+            for (int i = 1; i <= 5; i++) {
+                String url = URL_PREFIX + i;
+                executor.submit(new NewsThread(url));
+                if (i > 1)
+                    TimeUnit.SECONDS.sleep(10);
+            }
+        } catch (InterruptedException e) {
+            Thread.currentThread().interrupt();
+            System.err.println("Thread was interrupted, Failed to complete operation");
+        } finally {
+            executor.shutdown();
+            try {
+                if (!executor.awaitTermination(800, TimeUnit.MILLISECONDS))
+                    executor.shutdownNow();
+            } catch (InterruptedException e) {
+                executor.shutdownNow();
             }
-        } catch (Exception e) {
-            e.printStackTrace();
         }
     }
 }

src/server/tools/crawling/NewsThread.java

@@ -1,7 +1,9 @@
 package server.tools.crawling;
 
+import java.io.IOException;
 import java.sql.Connection;
 import java.sql.PreparedStatement;
+import java.sql.SQLException;
 
 import org.jsoup.Jsoup;
 import org.jsoup.nodes.Document;
@@ -14,63 +16,50 @@ public class NewsThread implements Runnable {
     private String urlPath;
 
     public NewsThread(String urlPath) {
-        super();
         this.urlPath = urlPath;
     }
 
     @Override
     public void run() {
-        String content = CrawlerTools.get(urlPath, "GB2312");
-        Document doc = Jsoup.parse(content);
-        Elements elements = doc.select(".bang_wrapper .bang_list_box ul li");
-        Connection con = DBConnection.getConnection();
-        PreparedStatement ps = null;
-        String sql = null;
-        int index = 0;
-        for (Element bookelement : elements) {
-            index++;
-            if (index >= 20)
-                break;
-            String title = bookelement.select(".name a").text();
-            Elements publisherInfoElements = bookelement.select(".publisher_info");
-            String author = null;
-            String publisher = null;
-            if (!publisherInfoElements.isEmpty()) {
-                Element firstPublisherInfoElement = publisherInfoElements.get(0);
-                Element secondPublisherInfoElement = publisherInfoElements.get(1);
-                author = firstPublisherInfoElement.select("a").text();
-                publisher = secondPublisherInfoElement.select("a").text();
-            }
-            String oprice = bookelement.select(".price_r").text();
-            String nprice = bookelement.select(".price_n").first().text();
-            String href = bookelement.select(".name a").attr("href");
-            double oldprice = Double.parseDouble(oprice.substring(1));
-            double newprice = Double.parseDouble(nprice.substring(1));
-            sql = "insert into book values(?,?,?,?,?,?)";
-            try {
-                ps = con.prepareStatement(sql);
-                ps.setString(1, title);
-                ps.setString(2, author);
-                ps.setString(3, publisher);
-                ps.setDouble(4, oldprice);
-                ps.setDouble(5, newprice);
-                ps.setString(6, href);
-                ps.executeUpdate();
-            } catch (Exception e) {
+        try {
+            String content = CrawlerTools.get(urlPath, "GB2312");
+            Document doc = Jsoup.parse(content);
+            Elements elements = doc.select(".bang_wrapper .bang_list_box ul li");
+            try (Connection con = DBConnection.getConnection()) {
+                for (Element bookElement : elements.subList(0, Math.min(elements.size(), 20))) {
+                    String title = bookElement.select(".name a").text();
+                    Elements publisherInfoElements = bookElement.select(".publisher_info");
+                    String author = publisherInfoElements.size() > 0 ? publisherInfoElements.get(0).select("a").text()
+                            : null;
+                    String publisher = publisherInfoElements.size() > 1
+                            ? publisherInfoElements.get(1).select("a").text()
+                            : null;
+                    String oprice = bookElement.select(".price_r").text();
+                    String nprice = bookElement.select(".price_n").first().text();
+                    String href = bookElement.select(".name a").attr("href");
+                    double oldprice = Double.parseDouble(oprice.substring(1));
+                    double newprice = Double.parseDouble(nprice.substring(1));
+                    insertBook(con, title, author, publisher, oldprice, newprice, href);
+                }
+            } catch (SQLException e) {
                 e.printStackTrace();
             }
-            System.out.println(title);
-            System.out.println(author);
-            System.out.println(publisher);
-            System.out.println(oldprice);
-            System.out.println(newprice);
-            System.out.println(href);
-        }
-        try {
-            ps.close();
-            con.close();
-        } catch (Exception e) {
+        } catch (IOException e) {
             e.printStackTrace();
         }
     }
+
+    private void insertBook(Connection con, String title, String author, String publisher, double oldprice,
+            double newprice, String href) throws SQLException {
+        String sql = "INSERT INTO book VALUES (?, ?, ?, ?, ?, ?)";
+        try (PreparedStatement ps = con.prepareStatement(sql)) {
+            ps.setString(1, title);
+            ps.setString(2, author);
+            ps.setString(3, publisher);
+            ps.setDouble(4, oldprice);
+            ps.setDouble(5, newprice);
+            ps.setString(6, href);
+            ps.executeUpdate();
+        }
+    }
 }

src/server/vo/User.java

@@ -45,9 +45,4 @@ public class User {
 	public void setRole(String role) {
 		this.role = role;
 	}
-
-	@Override
-	public String toString() {
-		return userName + "\t" + password + "\t" + name + "\t" + role;
-	}
 }