java jdbc connect

关于jdbc连接mysql数据库，是使用Java最原始的数据库连接，今天来复习一下：

1. 首先需要安装mysql客户端：mysql-installer-web-community-5.6.37.0.msi

2. 使用mysql jar包：mysql-connector-java-5.1.21.jar

3. 在eclipse上创建一个java项目：

4.把mysql jar包复制到/book-demo/WebContent/WEB-INF/lib中

5.点击jar包，点击鼠标右键：Build Path => Add to Build Path

6.创建一个属性文件：jdbc.properties

jdbc.driver=com.mysql.jdbc.Driver

jdbc.url=jdbc:mysql://127.0.0.1:3306/schema?useUnicode=true&characterEncoding=utf8

jdbc.username=

jdbc.password=

7.创建一个实体类，里面实现mysql连接：

package com.book.let.util;

 

import java.io.IOException;

import java.io.Serializable;

import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.PreparedStatement;

import java.sql.ResultSet;

import java.sql.SQLException;

import java.util.Properties;

 

import com.mysql.jdbc.Statement;

 

public final class DBUtil implements Serializable {

 

   /**

    *

    */

   private static final long serialVersionUID = -2765039977836078677L;

   private static Properties PROP =new Properties();

   static {

      try {

         PROP.load(DBUtil.class.getClassLoader().getResourceAsStream(

              "jdbc.properties"));

      } catch (IOExceptione) {

        // TODO Auto-generated catch block

        e.printStackTrace();

      }

 

   }

 

   private static final String JDBC_DRIVER =PROP.getProperty("jdbc.driver");

   private static final String JDBC_URL =PROP.getProperty("jdbc.url");

   private static final String JDBC_USERNAME =PROP

        .getProperty("jdbc.username");

   private static final String JDBC_PASSWORD =PROP

        .getProperty("jdbc.password");

 

   public static Connection openConn() {

      try {

        Class.forName(JDBC_DRIVER);

        Connection conn = DriverManager.getConnection(JDBC_URL,

              JDBC_USERNAME,JDBC_PASSWORD);

        returnconn;

      } catch (ClassNotFoundExceptione) {

        // TODO Auto-generated catch block

        e.printStackTrace();

      } catch (SQLExceptione) {

        // TODO Auto-generated catch block

        e.printStackTrace();

      }

      return null;

   }

 

   public static void closeConn(Connectionconn, Statementst,

        PreparedStatement ps, ResultSetrs) {

      if (conn ==null &&st == null &&ps == null &&rs == null)

        return;

      try {

        if (conn !=null && !conn.isClosed()) {

           conn.close();

        }

        if (st !=null && !st.isClosed()) {

           st.close();

        }

        if (ps !=null && !ps.isClosed()) {

           ps.close();

        }

        if (rs !=null && !rs.isClosed()) {

           rs.close();

        }

      } catch (SQLExceptione) {

        // TODO Auto-generated catch block

        e.printStackTrace();

      }

   }

}