【Web实战-Tomcat-Servlet-Thymeleaf -JDBC-MySQL】浏览器页面显示数据库数据（水果库存系统）

以下是一个简化的代码示例，展示了如何在Servlet中使用JDBC查询MySQL数据库，并通过Thymeleaf在浏览器中显示结果。

import org.thymeleaf.TemplateEngine;
import org.thymeleaf.context.WebContext;
import org.thymeleaf.templatemode.TemplateMode;
import org.thymeleaf.templateresolver.ServletContextTemplateResolver;
 
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.sql.*;
import java.util.ArrayList;
import java.util.List;
 
@WebServlet("/showData")
public class ShowDataServlet extends HttpServlet {
    private TemplateEngine templateEngine;
 
    @Override
    public void init() throws ServletException {
        super.init();
        ServletContextTemplateResolver templateResolver = new ServletContextTemplateResolver(getServletContext());
        templateResolver.setTemplateMode(TemplateMode.HTML);
        templateResolver.setPrefix("/WEB-INF/templates/");
        templateResolver.setSuffix(".html");
        templateEngine = new TemplateEngine();
        templateEngine.setTemplateResolver(templateResolver);
    }
 
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        List<String> dataList = new ArrayList<>();
 
        Connection connection = null;
        Statement statement = null;
        ResultSet resultSet = null;
        try {
            // 加载并注册JDBC驱动
            Class.forName("com.mysql.cj.jdbc.Driver");
            // 打开连接
            connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/mydb", "username", "password");
            // 执行查询
            statement = connection.createStatement();
            resultSet = statement.executeQuery("SELECT data FROM mytable");
            // 遍历结果集
            while (resultSet.next()) {
                dataList.add(resultSet.getString("data"));
            }
        } catch (ClassNotFoundException | SQLException e) {
            // 处理JDBC错误
            e.printStackTrace();
        } finally {
            // 关闭资源
            if (resultSet != null) resultSet.close();
            if (statement != null) statement.close();
            if (connection != null) connection.close();
        }
 
        // 设置请求属性，以便Thymeleaf可以处理它