【JDBC】一个Connection小工具类~

这几天学习jdbc的时候跟着视频写出来的一个用于连接数据库和释放对象的小工具类。
用到的类：druid(数据库连接池)下载地址：https://repo1.maven.org/maven2/com/alibaba/druid/1.1.23/
mysql驱动：
https://dev.mysql.com/downloads/
JdbcTemplate类
https://jar-download.com/artifacts/org.springframework/spring-jdbc

还需要两个配置文件分别是

和小工具类放在同一个包下
文件内容：

# druid.properties

driverClassName=com.mysql.cj.jdbc.Driver
url=jdbc:mysql://localhost:3306/db0
username=root
password=root
initialSize=5
maxActive=10
maxWait=3000

# jdbc.properties

url=jdbc:mysql://localhost:3306/db0
user=root
password=root
driver=com.mysql.cj.jdbc.Driver

package jdbcUtils;


import com.alibaba.druid.pool.DruidDataSourceFactory;

import javax.sql.DataSource;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStream;
import java.sql.*;
import java.util.Properties;



public class JDBCUtils {
    private static String url;
    private static String user;
    private static String password;
    private static String driver;

    private static DataSource ds;

    
    static {
        try {
            Properties pro = new Properties();
            String pro_name = "jdbc.properties";
            //获取路径
            //不要用classloader！
            String path = JDBCUtils.class.getResource(pro_name).getPath();
            //System.out.println(path);
            pro.load(new FileReader(path));
            url = pro.getProperty("url");
            user = pro.getProperty("user");
            password = pro.getProperty("password");
            driver = pro.getProperty("driver");
            //加载驱动
            Class.forName(driver);

        } catch (IOException | ClassNotFoundException e) {
            e.printStackTrace();
        }
    }

    
    static {
        try {
            Properties pro = new Properties();
            String pro_name = "druid.properties";
            InputStream is = JDBCUtils.class.getResourceAsStream(pro_name);
            pro.load(is);
            ds = DruidDataSourceFactory.createDataSource(pro);
        } catch (IOException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    
    public static Connection getConnection1() throws SQLException {
        return DriverManager.getConnection(url, user, password);
    }


    
    public static Connection getConnection2() throws SQLException {
        return ds.getConnection();
    }

    
    public static DataSource getDatasource(){
        return ds;
    }

    
    public static void close(Statement stmt, Connection conn) {
        
        JDBCUtils.close(null,stmt,conn);
    }

    //方法重载

    
    public static void close(ResultSet rs, Statement stmt, Connection conn) {
        if (rs != null) {
            try {
                rs.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        if (stmt != null) {
            try {
                stmt.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        if (conn != null) {
            try {
                conn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }

}

测试就很简单了

package jdbcUtils;

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

public class UtilsTest {
    public static void main(String[] args) throws Exception {
        String sql = "update stu set age = 22 where age = 20";
        Connection conn = JDBCUtils.getConnection1();

        // 获取执行sql的对象
        Statement stmt = conn.createStatement();
        // 执行sql
        int count  = stmt.executeUpdate(sql);
        System.out.println(count);
        // 释放资源
        JDBCUtils.close(stmt,conn);
    }
}