java如何连接mysql数据库
加载MySQL驱动
确保项目中包含MySQL的JDBC驱动。可以通过Maven添加依赖:
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.28</version>
</dependency>
建立数据库连接
使用DriverManager.getConnection()方法建立连接,需提供数据库URL、用户名和密码:
String url = "jdbc:mysql://localhost:3306/数据库名";
String username = "用户名";
String password = "密码";
Connection connection = DriverManager.getConnection(url, username, password);
执行SQL查询
通过Connection对象创建Statement或PreparedStatement执行SQL:
Statement statement = connection.createStatement();
ResultSet resultSet = statement.executeQuery("SELECT * FROM 表名");
// 使用PreparedStatement防止SQL注入
PreparedStatement preparedStatement = connection.prepareStatement("SELECT * FROM 表名 WHERE id = ?");
preparedStatement.setInt(1, 1);
ResultSet resultSet = preparedStatement.executeQuery();
处理查询结果
遍历ResultSet获取数据:
while (resultSet.next()) {
int id = resultSet.getInt("id");
String name = resultSet.getString("name");
System.out.println("ID: " + id + ", Name: " + name);
}
关闭资源
操作完成后关闭所有资源以释放连接:
resultSet.close();
statement.close();
connection.close();
异常处理
使用try-with-resources确保资源自动关闭:
try (Connection connection = DriverManager.getConnection(url, username, password);
PreparedStatement preparedStatement = connection.prepareStatement("SELECT * FROM 表名");
ResultSet resultSet = preparedStatement.executeQuery()) {
// 处理结果
} catch (SQLException e) {
e.printStackTrace();
}
连接池配置(可选)
对于生产环境,建议使用连接池如HikariCP:
HikariConfig config = new HikariConfig();
config.setJdbcUrl("jdbc:mysql://localhost:3306/数据库名");
config.setUsername("用户名");
config.setPassword("密码");
try (HikariDataSource dataSource = new HikariDataSource(config);
Connection connection = dataSource.getConnection()) {
// 使用连接
}






