后台技术学习1--Druid数据库连接池

url=jdbc:mysql://localhost:3306/数据库名
username=root
password=root
driverClassName=com.mysql.jdbc.Driver
#初始化连接数
initialSize=5
#最大连接数
maxActive=20
#最长等待时间
maxWait=2000

import com.alibaba.druid.pool.DruidDatasourceFactory;

import javax.sql.Datasource;
import java.io.InputStream;
import java.sql.Connection;
import java.util.Properties;

public class Demo1 {
    public static void main(String[] args) throws Exception {
        //加载配置文件
        Properties pro = new Properties();
        InputStream is = Demo1.class.getClassLoader().getresourceAsStream("druid.properties");
        pro.load(is);
        //获取连接池对象
        Datasource ds = DruidDatasourceFactory.createDatasource(pro);
        //获取链接
        Connection conn = ds.getConnection();
        System.out.println(conn);
    }
}

package utils;

import com.alibaba.druid.pool.DruidDatasourceFactory;

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

public class JDBCUtils {
    private static Datasource ds;
    static {
        try {
            Properties pro = new Properties();
            InputStream is = JDBCUtils.class.getClassLoader().getresourceAsStream("druid.properties");
            pro.load(is);
            ds = DruidDatasourceFactory.createDatasource(pro);
        } catch (Exception E) {
            e.printStackTrace();
        }
    }

    //获取链接
    public static Connection getConnection() throws SQLException {
        return ds.getConnection();
    }
    //释放资源
    public static void close(Statement stmt,Connection conn){
        if(stmt != null){
            try {
                stmt.close();
            } catch (SQLException E) {
                e.printStackTrace();
            }
        }
        if(conn != null){
            try {
                conn.close();
            } catch (SQLException E) {
                e.printStackTrace();
            }
        }
    }

    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();
            }
        }
    }

    //获取连接池
    public static Datasource getDs(){
        return ds;
    }
}