How to use MySQL and Java to implement a simple electronic signature function

Introduction:
In our daily lives, electronic signatures are becoming more and more common. It can be used in various situations, such as electronic contracts, electronic receipts and authorization documents, etc. This article will introduce how to use MySQL and Java to implement a simple electronic signature function, and provide specific code examples.

1. Create a database table
First, we need to create a table in MySQL to store electronic signature data. We create a table named "signature", which contains the following fields:

• id: The unique identifier of the signature record, which is an auto-incrementing primary key.
• name: The name of the signer.
• signature: Stores the binary data of the signature.
• date: Date and time of signature.

CREATE TABLE signature (
id INT AUTO_INCREMENT PRIMARY KEY,
name VARCHAR(100),
signature LONGBLOB,
date DATETIME
);

2. Implement Java code
Next, we will use Java to implement the electronic signature function. We use Java's Swing library to create the user interface. Here is a simple sample code:

import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.sql .*;
import javax.swing.*;

public class ElectronicSignature extends JFrame {
private JTextArea signatureTextArea;
private JButton saveButton;

public ElectronicSignature() {

// 設(shè)置窗口標(biāo)題
super("電子簽名");

// 創(chuàng)建界面元素
signatureTextArea = new JTextArea(10, 20);
saveButton = new JButton("保存簽名");

// 添加按鈕點(diǎn)擊事件監(jiān)聽器
saveButton.addActionListener(new ActionListener() {
  public void actionPerformed(ActionEvent e) {
    saveSignature();
  }
});

// 添加界面元素到窗口布局
setLayout(new FlowLayout());
add(signatureTextArea);
add(saveButton);

// 設(shè)置窗口大小、可見性和關(guān)閉操作
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setSize(300, 200);
setVisible(true);

}

private void saveSignature() {

try {
  // 獲取連接數(shù)據(jù)庫的URL、用戶名和密碼
  String url = "jdbc:mysql://localhost:3306/database_name";
  String user = "username";
  String password = "password";

  // 建立數(shù)據(jù)庫連接
  Connection conn = DriverManager.getConnection(url, user, password);

  // 創(chuàng)建SQL語句
  String sql = "INSERT INTO signature (name, signature, date) VALUES (?, ?, ?)";

  // 創(chuàng)建預(yù)編譯的語句
  PreparedStatement pstmt = conn.prepareStatement(sql);

  // 設(shè)置參數(shù)值
  pstmt.setString(1, "");
  pstmt.setBytes(2, signatureTextArea.getText().getBytes());
  pstmt.setTimestamp(3, new Timestamp(System.currentTimeMillis()));

  // 執(zhí)行SQL語句
  pstmt.executeUpdate();

  // 關(guān)閉預(yù)編譯的語句和數(shù)據(jù)庫連接
  pstmt.close();
  conn.close();

  // 提示保存成功信息
  JOptionPane.showMessageDialog(this, "簽名保存成功。");
} catch (Exception ex) {
  // 處理異常
  ex.printStackTrace();
  JOptionPane.showMessageDialog(this, "簽名保存失敗。");
}

}

public static void main(String[] args) {

new ElectronicSignature();

}
}

Code analysis:

• In the saveSignature method, we first get the connection to the MySQL database, then create an INSERT statement, and add the signature text and The current time is set as the parameter value. Finally, we execute the SQL statement and close the connection.
• If the save is successful, a prompt box will pop up to display the successful save information. Otherwise, a prompt box will pop up to display a message indicating that the save failed.

3. Run the code
Now, we can run the Java code and enter the signature content in the generated window. When we click on the "Save Signature" button, the signature will be saved to the MySQL database. If the save is successful, a prompt box will pop up to display the message that the save was successful; otherwise, a prompt box will pop up to display the message that the save failed.

Summary:
This article introduces how to use MySQL and Java to implement a simple electronic signature function. We created a data table named "signature" and created a window interface using Java's Swing library. By entering the signature content and clicking the "Save Signature" button, the signature will be saved to the MySQL database. With this example, you can further extend this functionality, integrate it with other applications, and refine the electronic signature functionality based on your actual needs.

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