以下是一个简单的Java程序,使用JDBC连接MySQL数据库,并执行一些基本的增删改查操作:
import java.sql.*; public class DBManager { private Connection conn; public DBManager() throws SQLException { String url = "jdbc:mysql://localhost:3306/mydb"; String username = "root"; String password = "password"; conn = DriverManager.getConnection(url, username, password); } public void addRecord(String name, int age) throws SQLException { PreparedStatement stmt = conn.prepareStatement("INSERT INTO records (name, age) VALUES (?, ?)"); stmt.setString(1, name); stmt.setInt(2, age); stmt.executeUpdate(); } public void updateRecord(int id, String name, int age) throws SQLException { PreparedStatement stmt = conn.prepareStatement("UPDATE records SET name=?, age=? WHERE id=?"); stmt.setString(1, name); stmt.setInt(2, age); stmt.setInt(3, id); stmt.executeUpdate(); } public void deleteRecord(int id) throws SQLException { PreparedStatement stmt = conn.prepareStatement("DELETE FROM records WHERE id=?"); stmt.setInt(1, id); stmt.executeUpdate(); } public void printRecords() throws SQLException { Statement stmt = conn.createStatement(); ResultSet rs = stmt.executeQuery("SELECT * FROM records"); while (rs.next()) { int id = rs.getInt("id"); String name = rs.getString("name"); int age = rs.getInt("age"); System.out.println("ID: " + id + ", Name: " + name + ", Age: " + age); } } public void closeConnection() throws SQLException { conn.close(); } public static void main(String[] args) throws SQLException { DBManager db = new DBManager(); // Add a record db.addRecord("John", 25); // Update a record db.updateRecord(1, "Jane", 30); // Delete a record db.deleteRecord(1); // Print all records db.printRecords(); db.closeConnection(); } }
在上面的代码中,我们创建了一个DBManager类来管理数据库连接和操作。在构造函数中,我们通过JDBC驱动程序获取了一个数据库连接。然后,我们定义了四个方法来执行增删改查操作:addRecord、updateRecord、deleteRecord和printRecords。这些方法使用预处理语句或语句对象执行SQL查询,并使用结果集处理查询结果。最后,我们使用main方法来测试这些操作,并在结束时关闭数据库连接。