实现加载驱动、得到数据库对象、关闭资源的代码复用，将代码提取到相应的工具包里边。优化程序

工具包

package com.xxx;

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

/**
 * 工具类
 * 
 */

public class Connectiontools {

	public static Connection getConn() {
		Connection conn = null;
		try {
			Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
			String url = "jdbc:sqlserver://localhost:1433;databaseName=test";
			String username = "zheng";
			String pwd = "123";
			conn = DriverManager.getConnection(url, username, pwd);
		} catch (SQLException e) {
			e.printStackTrace();
		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		}
		return conn;
	}

	// 关闭修改操作
	public static void close(Statement stmt, Connection conn) {
		try {
			if (stmt != null) {
				stmt.close();
			}
			if (conn != null) {
				conn.close();
			}
		} catch (SQLException e) {
			e.printStackTrace();
		}
	}

	// 关闭插入、插入等操作
	public static void close(Statement stmt, ResultSet rs, Connection conn) {
		try {
			if (stmt != null) {
				stmt.close();
			}
			if (rs != null) {
				rs.close();
			}
			if (conn != null) {
				conn.close();
			}
		} catch (SQLException e) {
			e.printStackTrace();
		}

	}

}

实现的操作

package com.xxx;

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

public class StatementDemo1 {

	private Connection conn = null;
	private Statement stmt = null;
	private ResultSet result = null;

	// 查询员工信息
	public void query() {
		// 1、加载驱动
		try {
			conn = Connectiontools.getConn();
			stmt = conn.createStatement();
			// 查询信息
			String selectstr = "select *from info";
			result = stmt.executeQuery(selectstr);
			// 4、处理结果集
			System.out.println("员工编号：\t员工姓名：\t工作：");
			while (result.next()) {
				System.out.println(result.getString("id") + "\t" + result.getString("name") + "\t" + "\t"
						+ result.getString("job"));
			}

		} catch (SQLException e) {
			e.printStackTrace();
		} finally {
			// 释放资源
			Connectiontools.close(stmt, result, conn);
		}

	}

	// 修改信息
	public void update() {
		try {
			// 1、加载驱动
			conn = Connectiontools.getConn();
			// 2、创建statement
			stmt = conn.createStatement();
			// 3、创建sql语句
			String updatestr = "update info set job='教授 ' where id='001'";
			int result = stmt.executeUpdate(updatestr);
			// 4、处理结果集
			if (result > 0) {
				System.out.println("更新成功！！！");
			} else {
				System.out.println("更新失败！！！");
			}
		} catch (SQLException e) {
			e.printStackTrace();
		} finally {
			Connectiontools.close(stmt, conn);
		}

	}

	public static void main(String[] args) {
		StatementDemo1 c = new StatementDemo1();
		c.query();
	}

}