Jdbc整合连接池

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.dashu</groupId>
    <artifactId>JdbcDriud</artifactId>
    <version>V1.0.1</version>
    <dependencies>
        <!--引入druid数据源-->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.1.8</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.25</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
            <scope>compile</scope>
        </dependency>
    </dependencies>
</project>

package com.dashu.util;
import com.alibaba.druid.pool.DruidDataSourceFactory;
import javax.sql.DataSource;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Properties;
/**
 * @Auther: DaShu
 * @Date: 2021/7/22 19:39
 * @Description:
 */
public class ConnUtil {
    private ConnUtil() {
    }
    private static DataSource dataSource;
    static {
        InputStream inStream = Thread.currentThread().getContextClassLoader().getResourceAsStream("dataSource.properties");
        Properties properties = new Properties();
        try {
            properties.load(inStream);
            dataSource = DruidDataSourceFactory.createDataSource(properties);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    /*
     * @Target:获取连接
     * @Author: DaShu
     * @Date: 2021/7/22 19:55
     * @Result:
     */
    public static Connection getConnection() {
        try {
            return dataSource.getConnection();
        } catch (Exception e) {
            e.printStackTrace();
            throw new RuntimeException("获取数据库连接异常");
        }
    }
    /*
     * @Target:释放资源
     * @Author: DaShu
     * @Date: 2021/7/22 19:54
     * @Result:
     */
    public static void close(ResultSet rSet, PreparedStatement pStatement, Connection connection) {
        try {
            if (rSet != null) {
                rSet.close();
            }
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            try {
                if (pStatement != null) {
                    pStatement.close();
                }
            } catch (SQLException e) {
                e.printStackTrace();
            } finally {
                try {
                    if (connection != null) {
                        connection.close();
                    }
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
        }
    }
}

package com.dashu;
import com.dashu.util.ConnUtil;
import org.junit.Test;
import java.sql.*;
/**
 * @Auther: DaShu
 * @Date: 2021/7/22 20:00
 * @Description:
 */
public class crud {
    @Test
    public void test() throws SQLException {
        Connection conn = null;
        try{
            conn= ConnUtil.getConnection();//从连接池获取链接
            conn.setAutoCommit(false);//开启事务
            PreparedStatement statement = conn.prepareStatement("insert into tree (id,name,age) values(?,?,?)");
            statement.setInt(1,7);
            statement.setString(2,"张天爱");
            statement.setInt(3,90);
            Boolean result =statement.execute();
            PreparedStatement stat = conn.prepareStatement("update tree set name = ?,age = ?  where id = ?");
            stat.setString(1,"张晓霞");
            stat.setInt(2,89);
            stat.setInt(3,2);
            Boolean results =stat.execute();
            conn.commit();//提交的那一刻数据就已经更新了。
            conn.close();
        } catch (Exception e) {
            conn.rollback();
            e.printStackTrace();
        }
    }
}

driverClassName=com.mysql.jdbc.Driver
url=jdbc:mysql://127.0.0.1:3306/tree
username=root
password=root