java zip文件插入数据库下载

以下是Java中将ZIP文件插入到数据库并下载的示例代码：

import java.io.*;
import java.sql.*;

public class ZipToDatabase {
    
    public static void main(String[] args) {
        String zipFilePath = "example.zip";
        String dbUrl = "jdbc:mysql://localhost:3306/mydb";
        String dbUser = "root";
        String dbPassword = "password";
        String tableName = "zip_files";
        
        try {
            // Read ZIP file into byte array
            byte[] zipFileBytes = readZipFile(zipFilePath);
            
            // Insert ZIP file into database
            insertZipFileIntoDatabase(zipFileBytes, dbUrl, dbUser, dbPassword, tableName);
            
            // Download ZIP file from database
            downloadZipFileFromDatabase(tableName, dbUrl, dbUser, dbPassword);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    
    // Read ZIP file into byte array
    public static byte[] readZipFile(String zipFilePath) throws IOException {
        File file = new File(zipFilePath);
        byte[] buffer = new byte[(int) file.length()];
        try (FileInputStream fis = new FileInputStream(file)) {
            fis.read(buffer);
        }
        return buffer;
    }
    
    // Insert ZIP file into database
    public static void insertZipFileIntoDatabase(byte[] zipFileBytes, String dbUrl, String dbUser, String dbPassword, String tableName) throws SQLException {
        try (Connection conn = DriverManager.getConnection(dbUrl, dbUser, dbPassword)) {
            String sql = "INSERT INTO " + tableName + "(file_data) VALUES(?)";
            try (PreparedStatement pstmt = conn.prepareStatement(sql)) {
                pstmt.setBytes(1, zipFileBytes);
                pstmt.executeUpdate();
            }
        }
    }
    
    // Download ZIP file from database
    public static void downloadZipFileFromDatabase(String tableName, String dbUrl, String dbUser, String dbPassword) throws SQLException, IOException {
        try (Connection conn = DriverManager.getConnection(dbUrl, dbUser, dbPassword)) {
            String sql = "SELECT file_data FROM " + tableName;
            try (PreparedStatement pstmt = conn.prepareStatement(sql)) {
                try (ResultSet rs = pstmt.executeQuery()) {
                    if (rs.next()) {
                        InputStream is = rs.getBinaryStream("file_data");
                        FileOutputStream fos = new FileOutputStream("downloaded.zip");
                        byte[] buffer = new byte[1024];
                        int len;
                        while ((len = is.read(buffer)) != -1) {
                            fos.write(buffer, 0, len);
                        }
                        fos.close();
                        is.close();
                    }
                }
            }
        }
    }
}

在此示例中，我们首先将ZIP文件读入字节数组中，然后将其插入到数据库中。我们使用预处理语句来执行SQL查询，并将字节数组传递给`setBytes()`方法。在下载ZIP文件时，我们使用`getBinaryStream()`方法获取`ResultSet`中的二进制流，并将其写入到本地文件中。