public void createServer(int port, ServerMsgPanel serverMsgPanel) throws IOException { long clientAccessNumber = 1L; this.serverMsgPanel = serverMsgPanel; try { this.serverSocket = new ServerSocket(port); serverMsgPanel.msgTextArea.setText("服务器启动于:" + InetAddress.getLocalHost() + ":" + this.serverSocket.getLocalPort() + "\n"); while(true) { Socket clientSocket = this.serverSocket.accept(); serverMsgPanel.msgTextArea.append("已连接用户:" + clientSocket + "\n"); DataOutputStream outputData = new DataOutputStream(clientSocket.getOutputStream()); this.clientDataHash.put(clientSocket, outputData); this.clientNameHash.put(clientSocket, "新玩家" + clientAccessNumber++); ServerThread serverThread = new ServerThread(clientSocket, this.clientDataHash, this.clientNameHash, this.chessPeerHash, serverMsgPanel); serverThread.start(); } } catch (IOException var8) { var8.printStackTrace(); } }

这段代码是用Java语言编写的创建服务器的方法。它打开一个ServerSocket，监听指定的端口，等待客户端连接。当有客户端连接时，会创建一个Socket对象，将客户端的输出流包装成DataOutputStream对象，并将客户端的Socket、DataOutputStream和客户端名称等信息存储在哈希表中。然后，启动一个ServerThread线程来处理与该客户端的通信。这个方法还接受一个ServerMsgPanel参数，用于在GUI界面上显示服务器的日志信息。

相关问题

java中excel文件的导入，限制上传的文件类型，文件的大小，显示上传文件的进度条...

要实现Java中的Excel文件导入，限制上传的文件类型，文件大小以及显示上传文件的进度条，可以借助以下几个技术：

1. Apache POI：用于读取和写入Excel文件
2. Apache Commons FileUpload：用于解析和处理文件上传请求
3. jQuery插件：用于实现显示上传文件的进度条

下面是一个简单的代码示例，演示了如何使用这些技术来实现文件上传和Excel文件导入：

import java.io.File;
import java.io.IOException;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileItemFactory;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.usermodel.Workbook;
import org.apache.poi.ss.usermodel.WorkbookFactory;

public class ExcelImportServlet extends HttpServlet {

    private static final long serialVersionUID = 1L;

    private static final int MAX_FILE_SIZE = 1024 * 1024; // 1MB

    private static final String[] ALLOWED_FILE_TYPES = {"xls", "xlsx"};

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        
        // Check if the request is a multipart/form-data POST request
        boolean isMultipart = ServletFileUpload.isMultipartContent(request);
        if (!isMultipart) {
            response.sendError(HttpServletResponse.SC_BAD_REQUEST, "Invalid request type");
            return;
        }
        
        // Create a factory for disk-based file items
        FileItemFactory factory = new DiskFileItemFactory();
        
        // Create a new file upload handler
        ServletFileUpload upload = new ServletFileUpload(factory);
        
        // Set maximum file size
        upload.setFileSizeMax(MAX_FILE_SIZE);
        
        try {
            // Parse the request
            List<FileItem> items = upload.parseRequest(request);
            for (FileItem item : items) {
                // Process only file upload request
                if (!item.isFormField()) {
                    // Check file type
                    String fileName = item.getName();
                    String fileType = fileName.substring(fileName.lastIndexOf(".") + 1).toLowerCase();
                    boolean isAllowedType = false;
                    for (String allowedType : ALLOWED_FILE_TYPES) {
                        if (fileType.equals(allowedType)) {
                            isAllowedType = true;
                            break;
                        }
                    }
                    if (!isAllowedType) {
                        response.sendError(HttpServletResponse.SC_BAD_REQUEST, "Invalid file type");
                        return;
                    }
                    
                    // Create a temporary file to store the uploaded file
                    File tempFile = File.createTempFile("excel-import-", "." + fileType);
                    item.write(tempFile);
                    
                    // Read the uploaded Excel file
                    Workbook workbook = WorkbookFactory.create(tempFile);
                    Sheet sheet = workbook.getSheetAt(0);
                    for (Row row : sheet) {
                        for (Cell cell : row) {
                            // Process cell data
                        }
                    }
                    
                    // Delete the temporary file
                    tempFile.delete();
                    
                    // Send success response
                    response.getWriter().write("File uploaded and processed successfully!");
                }
            }
        } catch (Exception e) {
            response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR, "Error processing file upload");
            e.printStackTrace();
        }
    }

}

此外，还需要在前端页面中使用jQuery插件来实现上传文件进度条的显示。可以使用一些流行的jQuery插件，例如 jQuery File Upload 或 Dropzone.js。

希望以上内容能够对你有所帮助！

1.自建数据库（数据库产品自选SQL server MySQL Oracle等任选），新建一个user表，至少包含用户名和密码两个字段 2.新建一个登录页面 3.编写处理登录页面的servlet，在servlet中利用JDBC连接数据库，并进行登录的验证操作。 4.根据servlet中处理的结果，跳转到登录成功或者失败的JSP页面。

好的，我可以为您提供一个实现登录验证的示例代码。首先，您需要在您选择的数据库中创建一个名为"user"的表，该表包含id、username和password三个字段。下面是示例代码：

1. 创建user表的SQL语句（以MySQL为例）：

CREATE TABLE user (
  id INT(11) NOT NULL AUTO_INCREMENT,
  username VARCHAR(50) NOT NULL,
  password VARCHAR(50) NOT NULL,
  PRIMARY KEY (id)
);

2. 创建登录页面的HTML代码：

<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>Login Page</title>
</head>
<body>
    <h2>Login Page</h2>
    <form action="login" method="post">
        <p>
            <label>Username:</label>
            <input type="text" name="username" required>
        </p>
        <p>
            <label>Password:</label>
            <input type="password" name="password" required>
        </p>
        <p>
            <input type="submit" value="Login">
        </p>
    </form>
</body>
</html>

3. 创建处理登录请求的servlet：

import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@WebServlet("/login")
public class LoginServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;

    private static final String URL = "jdbc:mysql://localhost:3306/test";
    private static final String USERNAME = "root";
    private static final String PASSWORD = "123456";

    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        String username = request.getParameter("username");
        String password = request.getParameter("password");
        boolean isValidUser = validateUser(username, password);
        if (isValidUser) {
            request.getRequestDispatcher("success.jsp").forward(request, response);
        } else {
            request.getRequestDispatcher("failure.jsp").forward(request, response);
        }
    }

    private boolean validateUser(String username, String password) {
        try (Connection connection = DriverManager.getConnection(URL, USERNAME, PASSWORD)) {
            String sql = "SELECT * FROM user WHERE username = ? AND password = ?";
            try (PreparedStatement statement = connection.prepareStatement(sql)) {
                statement.setString(1, username);
                statement.setString(2, password);
                try (ResultSet resultSet = statement.executeQuery()) {
                    return resultSet.next();
                }
            }
        } catch (SQLException e) {
            e.printStackTrace();
            return false;
        }
    }
}

4. 创建登录成功和失败的JSP页面：

success.jsp

<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>Login Success</title>
</head>
<body>
    <h2>Login Success</h2>
    <p>Welcome <%= request.getParameter("username") %>!</p>
</body>
</html>

failure.jsp

<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>Login Failure</title>
</head>
<body>
    <h2>Login Failure</h2>
    <p>Invalid username or password.</p>
</body>
</html>

需要注意的是，示例代码中使用了try-with-resources语句来自动关闭JDBC连接和资源，以确保代码的健壮性和可靠性。

希望这个示例代码能够帮助您实现登录验证功能。