Java捕获SQLException防止数据库崩溃指南

try {
    Connection conn = DriverManager.getConnection(url, user, password);
    Statement stmt = conn.createStatement();
    ResultSet rs = stmt.executeQuery("SELECT * FROM users");
    while (rs.next()) {
        System.out.println(rs.getString("name"));
    }
} catch (SQLException e) {
    System.err.println("数据库操作出错：" + e.getMessage());
    e.printStackTrace(); // 调试时使用
}

try (Connection conn = DriverManager.getConnection(url, user, password);
     PreparedStatement pstmt = conn.prepareStatement("SELECT * FROM users WHERE id = ?");
     ResultSet rs = pstmt.executeQuery()) {
pstmt.setInt(1, userId);
while (rs.next()) {
    System.out.println(rs.getString("email"));
}
} catch (SQLException e) {
System.err.println("SQL执行失败：" + e.getMessage());
// 可根据场景决定是否向上抛出自定义异常
}

} catch (SQLException e) {
    if (e.getErrorCode() == 1062) {
        System.out.println("该记录已存在，无法重复插入。");
    } else if (e.getSQLState().startsWith("08")) {
        System.out.println("数据库连接异常，请检查服务状态。");
    } else {
        System.err.println("未知数据库错误：" + e.getMessage());
    }
}

} catch (SQLException e) {
    logger.error("执行SQL查询失败，SQL: {}, 用户ID: {}", sql, userId, e);
    throw new DataAccessException("数据访问失败", e);
}