jaca代码用户查看、上传、下载、图片、文档

很抱歉，我是一名语言模型，无法提供实时的代码查看、上传、下载、图片、文档等功能。不过，以下是一些Java代码示例，供您参考。

用户查看：

public class User {
    private String username;
    private String password;
    private String email;

    public User(String username, String password, String email) {
        this.username = username;
        this.password = password;
        this.email = email;
    }

    public String getUsername() {
        return username;
    }

    public String getPassword() {
        return password;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }
}

用户上传：

public void uploadFile(File file) {
    try {
        // create a new FTP client
        FTPClient ftpClient = new FTPClient();
        
        // connect to the FTP server
        ftpClient.connect("ftp.example.com");
        
        // login to the FTP server
        ftpClient.login("username", "password");
        
        // set file type to binary
        ftpClient.setFileType(FTP.BINARY_FILE_TYPE);
        
        // upload the file
        FileInputStream inputStream = new FileInputStream(file);
        ftpClient.storeFile(file.getName(), inputStream);
        
        // logout and disconnect from the FTP server
        ftpClient.logout();
        ftpClient.disconnect();
        
        System.out.println("File uploaded successfully.");
    } catch (IOException ex) {
        System.out.println("Error uploading file: " + ex.getMessage());
    }
}

用户下载：

public void downloadFile(String fileName) {
    try {
        // create a new FTP client
        FTPClient ftpClient = new FTPClient();
        
        // connect to the FTP server
        ftpClient.connect("ftp.example.com");
        
        // login to the FTP server
        ftpClient.login("username", "password");
        
        // set file type to binary
        ftpClient.setFileType(FTP.BINARY_FILE_TYPE);
        
        // download the file
        FileOutputStream outputStream = new FileOutputStream(fileName);
        ftpClient.retrieveFile(fileName, outputStream);
        
        // logout and disconnect from the FTP server
        ftpClient.logout();
        ftpClient.disconnect();
        
        System.out.println("File downloaded successfully.");
    } catch (IOException ex) {
        System.out.println("Error downloading file: " + ex.getMessage());
    }
}

用户图片：

import java.awt.Graphics;
import java.awt.Image;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;

public class ImageExample {
    public static void main(String[] args) throws IOException {
        // read image file
        File file = new File("image.jpg");
        BufferedImage image = ImageIO.read(file);
        
        // resize image
        Image resizedImage = image.getScaledInstance(200, 200, Image.SCALE_SMOOTH);
        
        // create new image with resized dimensions
        BufferedImage resizedBufferedImage = new BufferedImage(200, 200, BufferedImage.TYPE_INT_RGB);
        Graphics g = resizedBufferedImage.createGraphics();
        g.drawImage(resizedImage, 0, 0, null);
        g.dispose();
        
        // display image in a new window
        JFrame frame = new JFrame("Image Example");
        JLabel label = new JLabel(new ImageIcon(resizedBufferedImage));
        frame.getContentPane().add(label);
        frame.pack();
        frame.setVisible(true);
    }
}

用户文档：

import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;

public class DocumentExample {
    public static void main(String[] args) throws IOException {
        // create new file
        File file = new File("document.txt");
        file.createNewFile();
        
        // write to file
        FileWriter writer = new FileWriter(file);
        BufferedWriter buffer = new BufferedWriter(writer);
        buffer.write("This is a sample document.");
        buffer.newLine();
        buffer.write("It contains some text.");
        buffer.newLine();
        buffer.write("And some more text.");
        buffer.close();
        
        System.out.println("Document created successfully.");
    }
}