在Java中，我们可以使用JDBC(Java Database Connectivity)或者JPA(Java Persistence API)来实现对数据库的操作，以下是一个简单的示例：

我们需要创建一个连接数据库的工具类：

```java

import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.SQLException;

public class DBUtil {

private static final String URL = "jdbc:mysql://localhost:3306/myDB";

private static final String USERNAME = "username";

private static final String PASSWORD = "password";

public static Connection getConnection() {

Connection conn = null;

try {

Class.forName("com.mysql.jdbc.Driver");

conn = DriverManager.getConnection(URL, USERNAME, PASSWORD);

} catch (ClassNotFoundException | SQLException e) {

e.printStackTrace();

}

return conn;

}

```

我们可以在Servlet中使用这个工具类来查询数据库：

```java

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.Connection;

import java.sql.PreparedStatement;

import java.sql.ResultSet;

import java.util.ArrayList;

import java.util.List;

@WebServlet("/SearchServlet")

public class SearchServlet extends HttpServlet {

@Override

protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

String searchWord = req.getParameter("search_word");