JDBC—JDBC的工具类抽取

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JDBC的工具类抽取

为了简化JDBC的开发，可以将一些重复的代码进行提取

编写工具类

JDBCutils.java

package com.jdbc.dream.utils;

import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;

/**
 * JDBC工具类
 * @author Jun
 *
 */
public class JDBCutils {
	/*静态常量*/
	private static String url=null;
	private static String username=null;
	private static String password=null;
	
	static {
		// 加载属性文件并解析
		Properties profile = new Properties();
		// 通常情况下采用类的加载器的方式来进行获取
		InputStream is = JDBCutils.class.getClassLoader().getResourceAsStream("jdbc.properties");
		try {
			profile.load(is);		
		} catch (IOException e) {
			e.printStackTrace();
		}
		
		// 赋值
		url=profile.getProperty("url");
		username=profile.getProperty("username");
		password=profile.getProperty("password");
	}
	
	
	
	/**
	 *	连接数据库方法
	 * @throws SQLException 
	 */
	public static Connection getConnection() throws SQLException {
		Connection conn = DriverManager.getConnection(url,username,password);
		return conn;
	}
	
	/**
	 *	资源释放
	 */
	public static void release(Statement stat,Connection conn) {
		if(stat!=null) {
			try {
				stat.close();
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
			stat=null;
		}
		
		if(conn!=null) {
			try {
				stat.close();
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
			stat=null;
		}
	}
	
	public static void release(ResultSet res,Connection conn,Statement stat) {
		if(res!=null) {
			try {
				stat.close();
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
			res=null;
		}
		
		if(stat!=null) {
			try {
				stat.close();
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
			stat=null;
		}
		
		if(conn!=null) {
			try {
				stat.close();
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
			stat=null;
		}
	}

	
}

为了方便后期维护，可以将数据存在在配置文件中，注意：要存放啦src文件中

jdbc.properties

url=jdbc:mysql://localhost:3306/jdbctest?useSSL=false&serverTimezone=Hongkong&useUnicode=true&characterEncoding=utf-8
username=root
password=1916

demo1.java

package com.dream.demo2;

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

import org.junit.Test;

import com.jdbc.dream.utils.JDBCutils;

public class demo1 {
	
	@Test
	public void jdbcdemo1() {
		Connection conn = null;
		Statement stat = null;
		ResultSet res = null;
		
		try {
			// 连接数据库
			conn = JDBCutils.getConnection();
			// 编写SQL语句
			String sql = "insert user values (null,'fff','666','大八')";
			String sql1 = "select * from user";
			// 执行SQL语句
			stat=conn.createStatement();
			int i = stat.executeUpdate(sql);
			res = stat.executeQuery(sql1);
			if(i>0) {
				System.out.println("插入成功！");
				while(res.next()) {
					int id = res.getInt("uid");
					String username = res.getString("username");
					String pas = res.getString("password");
					String name = res.getString("name");
					System.out.println(id+"\t"+username+"\t"+pas+"\t"+name);
				}
			}
		} catch (Exception e) {
			// TODO: handle exception
		} finally {
			JDBCutils.release(res, conn, stat);
		}
	}
}