package com.itechzero.util;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

/**
 * DbUtil.java
 * 
 * @author Techzero
 * @Email techzero@163.com
 * @Time 2014-2-18 下午3:16:35
 */
public class DbUtil {
	private Connection conn;
	private Statement stmt;
	private ResultSet rs;

	// MySQL
	private final String DBDRIVER = "org.gjt.mm.mysql.Driver";
	private final String DBURL = "jdbc:mysql://127.0.0.1:3306/db_test";
	private final String USERNAME = "root";
	private final String USERPWD = "123456";

	// SQLServer
	// private final String DBDRIVER =
	// "com.microsoft.sqlserver.jdbc.SQLServerDriver";
	// private final String DBURL =
	// "jdbc:sqlserver://127.0.0.1:1433;databaseName=db_test";
	// private final String USERNAME = "sa";
	// private final String USERPWD = "123";

	// 取得连接
	private boolean getConnection() {
		try {
			Class.forName(DBDRIVER);
			conn = DriverManager.getConnection(DBURL, USERNAME, USERPWD);
			return true;
		} catch (Exception e) {
			e.printStackTrace();
			return false;
		}
	}

	// 查询
	public ResultSet query(String sql) {
		if (getConnection()) {
			try {
				stmt = conn.createStatement();
				rs = stmt.executeQuery(sql);
				return rs;
			} catch (SQLException e) {
				e.printStackTrace();
				return null;
			}
		} else {
			return null;
		}
	}

	// 修改
	public int update(String sql) {
		if (getConnection()) {
			try {
				stmt = conn.createStatement();
				int flag = stmt.executeUpdate(sql);
				return flag;
			} catch (Exception e) {
				e.printStackTrace();
				return -1;
			}
		} else {
			return -1;
		}
	}

	// 关闭连接
	public boolean closeAll() {
		try {
			if (rs != null)
				rs.close();
			if (stmt != null)
				stmt.close();
			if (conn != null)
				conn.close();
			return true;
		} catch (Exception e) {
			e.printStackTrace();
			return false;
		}
	}
}

Java 最简单的 数据库工具类 DbUtil