edu.aeon.aeonutils;
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;
/**
* [说明]:jdbc工具类
* 封装了jdbc里面的重复步骤:数据库的连接和数据库资源的释放
* @author aeon
* @version 1.2(该版本将连接数据库的各种数据库配置信息(用户名、密码、驱动及url)单独提取到配置文件中)
*/
public class AeonJdbcUtils {
private static String username;
private static String password;
private static String driverClass;
private static String url;
/**
* 静态代码块处理读取之前的数据
*/
static{
InputStream inputStream = AeonJdbcUtils.
class.getClassLoader().getResourceAsStream("config/database/database.properties"
);
Properties properties=
new Properties();
try {
properties.load(inputStream);
username = properties.getProperty("username"
);
password = properties.getProperty("password"
);
driverClass = properties.getProperty("driverClass"
);
url = properties.getProperty("url"
);
} catch (IOException e) {
System.out.println("初始化读取数据库配置文件--->database.properties失败！"
);
e.printStackTrace();
}
}
/**
* 连接数据库
* @return 数据库连接对象
* @throws ClassNotFoundException
* @throws SQLException
*/
public static Connection getMySqlConnection()
throws ClassNotFoundException, SQLException{
Class.forName(driverClass);
return DriverManager.getConnection(url, username, password);
}
/**
* 释放数据库资源
* @param resultSet 结果集
* @param statement 执行sql语句的对象
* @param connection 数据库连接对象
*/
public static void closeDB(ResultSet resultSet,Statement statement,Connection connection){
if(
null!=
resultSet){
try {
resultSet.close();
} catch (SQLException e) {
System.out.println("释放数据库资源失败！--->resultSet"
);
e.printStackTrace();
}
}
if(
null!=
statement){
try {
statement.close();
} catch (SQLException e) {
System.out.println("释放数据库资源失败！--->statement"
);
e.printStackTrace();
}
}
if(
null!=
connection){
try {
connection.close();
} catch (SQLException e) {
System.out.println("释放数据库资源失败！--->connection"
);
e.printStackTrace();
}
}
}
}
测试代码:
package edu.aeon.aeonutils;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
/**
* [说明]:测试连接数据库工具类(version 1.2)
* @author aeon
*
*/
public class TestAeonJdbcUtils {
public static void main(String[] args) {
Connection connection = null;
Statement statement = null;
ResultSet resultSet = null;
try {
connection = AeonJdbcUtils.getMySqlConnection();
statement = connection.createStatement();
String sql = "select * from user";
resultSet = statement.executeQuery(sql);
System.out.println("用户id\t用户名\t用户密码");
while (resultSet.next()) {
int userId = resultSet.getInt("userId");// 根据表字段名获取该行记录上的字段名所对应的字段值
String userName = resultSet.getString("userName");
String userPw = resultSet.getString("userpw");// 数据库中的字段不区分大小写
System.out.println(userId + "\t" + userName + "\t" + userPw);
}
} catch (ClassNotFoundException e) {
System.out.println("加载驱动失败!");
e.printStackTrace();
} catch (SQLException e) {
System.out.println("连接数据库失败!");
e.printStackTrace();
}
AeonJdbcUtils.closeDB(resultSet, statement, connection);
}
}
database.properties中的配置信息：
username=root
password=root
driverClass=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/db_test
项目包视图截图如下：
建库及表语句：
drop database db_test;
create database db_test;
use db_test;
create table user(
userId int(5) primary key comment ‘用户id‘,
userName varchar(16) comment ‘用户姓名‘,
userPw varchar(16) comment ‘用户密码‘
);
insert into user(userId,userName,userPw) values(10001,‘user1‘,‘user1‘);
insert into user(userId,userName,userPw) values(10002,‘user2‘,‘user2‘);
insert into user(userId,userName,userPw) values(10003,‘user3‘,‘user3‘);
insert into user(userId,userName,userPw) values(10004,‘user4‘,‘user4‘);
insert into user(userId,userName,userPw) values(10005,‘user5‘,‘user5‘);
数据库信息截图：
测试结果截图：
dljd_011_jdbc再次封装工具类_把数据库的相关信息写到配置文件中,减低代码的耦合度
标签：tst 用户密码 9.png create 说明 NPU closed driver 加载
