基于Druid的JDBCUtils类

首先需要一个名为druid.properties的配置文件，如下

driverClassName=com.mysql.cj.jdbc.Driver
url=jdbc:mysql://127.0.0.1:3306/ittest
username=root
password=123456
# 初始化连接数量
initialSize=5
# 最大连接数
maxActive=10
# 最大等待时间
maxWait=3000

再编写JDBCUtils的代码，如下

package com.sun.utils;
 
import com.alibaba.druid.pool.DruidDataSourceFactory;
 
import javax.sql.DataSource;
import java.io.IOException;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;
 
//Druid连接池的工具类
public class JDBCUtils {
    //1、定义成员变量
    private static DataSource ds;
 
    static{
        try {
            //1、加载配置文件
            Properties pro = new Properties();
            pro.load(JDBCUtils.class.getClassLoader().getResourceAsStream("druid.properties"));
            //2、获取DataSource
            DruidDataSourceFactory.createDataSource(pro);
        } catch (IOException e) {
            throw new RuntimeException(e);
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }
    //获取连接
    public static Connection getConnection() throws SQLException {
        //从连接池获取连接对象
        return ds.getConnection();
    }
    //释放资源
    public static void close(Statement stmt,Connection conn){
        close(null,stmt,conn);
    }
    public static void close(ResultSet rs,Statement stmt,Connection conn){
        if (rs != null){
            try {
                rs.close();
            } catch (SQLException e) {
                throw new RuntimeException(e);
            }
        }
        if (stmt != null){
            try {
                stmt.close();
            } catch (SQLException e) {
                throw new RuntimeException(e);
            }
        }
        if (conn != null){
            try {
                conn.close();
            } catch (SQLException e) {
                throw new RuntimeException(e);
            }
        }
    }
    //获取连接池对象
    public static DataSource getDataSource(){
        return ds;
    }
}

JDBCUtils的使用

package com.sun.datasourceStudy.druid;
 
import com.sun.utils.JDBCUtils;
 
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.SQLException;
 
//使用Druid工具类
public class DruidUtilsTest {
    public static void main(String[] args) {
        //完成添加操作，给tb_user表添加一条记录
        Connection conn = null;
        PreparedStatement pstmt =null;
        try {
            //1、获取连接
            conn = JDBCUtils.getConnection();
            //2、定义sql
            String sql = "insert into tb_user values(null,?,?,?)";
            //3、获取pstmt对象
            pstmt = conn.prepareStatement(sql);
            //4、给?赋值
            pstmt.setString(1,"李筱思");
            pstmt.setInt(2,22);
            pstmt.setString(3,"女");
            //5、执行sql
            int count = pstmt.executeUpdate();
            System.out.println(count);
        } catch (SQLException e) {
            throw new RuntimeException(e);
        } finally {
            //6、释放资源
            JDBCUtils.close(pstmt,conn);
        }
 
    }
}