Java如何调用Halo数据库（三）-DriverManager

public static void register() throws SQLException {
  if (isRegistered()) {
    throw new IllegalStateException(
        "Driver is already registered. It can only be registered once.");
  }
  Driver registeredDriver = new Driver();
  DriverManager.registerDriver(registeredDriver);
  Driver.registeredDriver = registeredDriver;
}

 public static void deregister() throws SQLException {
    if (registeredDriver == null) {
      throw new IllegalStateException(
          "Driver is not registered (or it has not been registered using Driver.register() method)");
    }
    DriverManager.deregisterDriver(registeredDriver);
    registeredDriver = null;
  }

private synchronized Properties getDefaultProperties() throws IOException {
    if (defaultProperties != null) {
      return defaultProperties;
    }

    // Make sure we load properties with the maximum possible privileges.
    try {
      defaultProperties =
          AccessController.doPrivileged(new PrivilegedExceptionAction<Properties>() {
            public Properties run() throws IOException {
              return loadDefaultProperties();
            }
          });
    } catch (PrivilegedActionException e) {
      throw (IOException) e.getException();
    }

    return defaultProperties;

public class JdbcDriverManagerTest {
    private static final String URL = "jdbc:halo://localhost:1921/test";
    private static final String USER = "root";
    private static final String PASSWORD = "123456";
    public void testJdbcRaw() throws Exception {
        Class.forName("com.halo.Driver");
        Connection conn = DriverManager.getConnection(URL, USER, PASSWORD);
        Statement stmt = conn.createStatement();
        // PreparedStatement ptmt = conn.prepareStatement(sql); 
        ResultSet rs = stmt.executeQuery("SELECT username, age FROM user");
        while(rs.next()){
            System.out.println(“”);
        }
        conn.close();
    }}

3、管理连接池

import com.zaxxer.hikari.HikariConfig;
import com.zaxxer.hikari.HikariDataSource;
import java.sql.Connection;

import java.sql.SQLException;
public class JDBCDemo {
    public static void main(String[] args) {
        HikariConfig config = new HikariConfig();
        config.setJdbcUrl("jdbc:halo://localhost:1921/test");
        config.setUsername("root");
        config.setPassword("password");
        // 创建 Hikari 数据源
        HikariDataSource dataSource = new HikariDataSource(config);
        try {
            // 从连接池获取连接
            Connection connection = dataSource.getConnection();
            // 在此处执行数据库操作
            // 关闭连接
            connection.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}