SQL学习笔记之数据库专题（四）：浅谈JDBC用法(二)

配置文件内容如下：

driver=com.mysql.jdbc.Driver
url=jdbc:mysql:///freedom
user=root
password=root

看工具类：

import java.io.FileReader;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;
public class JDBCUtils {
	private static Properties prop = null;
	private JDBCUtils() {
	}
	static{
		try{
			prop = new Properties();
			prop.load(new FileReader(JDBCUtils.class.getClassLoader().getResource("config.properties").getPath()));
		}catch (Exception e) {
			e.printStackTrace();
			throw new RuntimeException(e);
		}
	}
	
	/**
	 * 获取连接
	 * @throws ClassNotFoundException 
	 * @throws SQLException 
	 */
	public static Connection getConn() throws ClassNotFoundException, SQLException{
		// 1.注册数据库驱动
		Class.forName(prop.getProperty("driver"));
		// 2.获取连接
		return DriverManager.getConnection(prop.getProperty("url"), prop.getProperty("user"), prop.getProperty("password"));
		
	}
	/**
	 * 关闭连接
	 */
	public static void close(ResultSet rs, Statement stat,Connection conn){
		if(rs!=null){
			try {
				rs.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}finally{
				rs = null;
			}
		}
		if(stat!=null){
			try {
				stat.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}finally{
				stat = null;
			}
		}
		if(conn!=null){
			try {
				conn.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}finally{
				conn = null;
			}
		}
	
	}
}

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

import org.junit.Test;

import com.itheima.util.JDBCUtils;

public class FreedomJDBC {

	/**
	 * @Title: add
	 * @Description: 增加
	 * @throws
	 */
	@Test
	public void add() {
		Connection conn = null;
		Statement stat = null;
		try {
			// 1.注册数据库驱动
			// 2.获取连接
			conn = JDBCUtils.getConn();
			// 3.获取传输器对象
			stat = conn.createStatement();
			// 4.执行sql语句
			int count = stat
					.executeUpdate("insert into user values (null,'freedom','123456','freedom@qq.com','2012-01-01')");
			// 5.处理结果
			if (count > 0) {
				System.out.println("执行成功!影响到的行数为" + count);
			} else {
				System.out.println("执行失败!!");
			}

		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			// 6.关闭资源
			JDBCUtils.close(null, stat, conn);
		}
	}

	/**
	 * @Title: delete
	 * @Description:删除
	 * @throws
	 */
	@Test
	public void delete() {
		Connection conn = null;
		Statement stat = null;
		ResultSet rs = null;
		try {
			conn = JDBCUtils.getConn();
			stat = conn.createStatement();
			stat.executeUpdate("delete from user where name='freedom'");
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			JDBCUtils.close(rs, stat, conn);
		}
	}

	/**
	 * @Title: update
	 * @Description: 更新
	 * @throws
	 */
	@Test
	public void update() {
		Connection conn = null;
		Statement stat = null;
		try {
			conn = JDBCUtils.getConn();
			stat = conn.createStatement();
			stat
					.executeUpdate("update user set password=666 where name='freedom'");
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			JDBCUtils.close(null, s