Java JDBC 示例-优快云博客

本文提供了一个使用 Java JDBC 连接 MySQL 数据库的示例代码。该示例展示了如何加载驱动、建立连接、执行 SQL 查询和更新操作，同时给出了关闭资源的方法。

转 http://www.cnblogs.com/harrysun/archive/2012/09/17/2688109.html

package ct;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;



public class JDBCDemo {
	public static final String DRIVER = "com.mysql.jdbc.Driver";
	public static final String URL = "jdbc:mysql://ip:3306/name";
	public static final String USERNAME = "n";
	public static final String PASSWORD = "p";

	Connection connection = null;
	PreparedStatement preparedStatement = null;
	ResultSet resultSet = null;

	public Connection getConnection() throws Exception {
		Class.forName(DRIVER);
		connection = DriverManager.getConnection(URL, USERNAME, PASSWORD);
		return connection;
	}

	public ResultSet executeQuery(String sql) throws Exception {
		connection = this.getConnection();
		preparedStatement = connection.prepareStatement(sql);
		resultSet = preparedStatement.executeQuery();
		return resultSet;

	}

	public int executeUpdate(String sql, Object[] obj) throws Exception {
		connection = this.getConnection();
		preparedStatement = connection.prepareStatement(sql);
		for (int i = 0; i < obj.length; i++) {
			preparedStatement.setObject(i + 1, obj[i]);
		}
		return preparedStatement.executeUpdate();
	}

	public void closeAll() throws Exception {
		if (null != resultSet) {
			resultSet.close();
		}
		if (null != preparedStatement) {
			preparedStatement.close();
		}
		if (null != connection) {
			connection.close();
		}
	}
}

调用
private static String getWeixinId() {
		String sql = "select * ";
		JDBCDemo jdbc = new JDBCDemo();
		String restr = "";
		try {
			ResultSet rs = jdbc.executeQuery(sql);
			ResultSetMetaData rsmd = rs.getMetaData();
			int j = rsmd.getColumnCount();
			while (rs.next()) {
				for (int i = 0; i < j; i++) {
					restr += rs.getString(i + 1) + ",";
				}
			}
			if (restr.endsWith(",")) {
				restr = restr.substring(0, restr.length() - 1);
			}
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			try {
				jdbc.closeAll();
			} catch (Exception e) {
				e.printStackTrace();
			}
		}
		return restr;
	}