DBCP线程池的练习中出现 org/apache/commons/logging/LogFactory错误…

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DBCP线程池的练习

因为中间有其他包，所以分开截图的。

package Test_DBCP;

import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.Properties;

import javax.sql.DataSource;

import org.apache.commons.dbcp2.BasicDataSourceFactory;

/*
* 1.导入jar包
* 2.配置文件 dbcp.properties（配置数据库所连接的信息）要放在src路径下
* */
public class dbcpTest {

private static DataSource ds;//import javax.sql.DataSource;

   static {

       try {
           //InputStream is=new FileinputStream(“路径是写死的”);
           //将dbcp.properties先用输入了读进来，然后load()装载，再赋给ds.
           //dbcpTest.class获取当前类的类对象，getClassLoader()获取当前类的加载器，dbcp.properties在类的根路径(src)下
           //getSystemResourceAsStream()获取类加载器中的资源。
           InputStream is = dbcpTest.class.getClassLoader().getSystemResourceAsStream(“dbcp.properties”);
           Properties properties = new Properties();
           properties.load(is);
           ds = BasicDataSourceFactory.createDataSource(properties);

       } catch (IOException e1) {
           // TODO Auto-generated catch block
           e1.printStackTrace();
       }
       catch (Exception e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       }
   }

   public static void main(String[] args) throws SQLException {
       // TODO Auto-generated method stub

           Connection conn = ds.getConnection();
           System.out.println(conn);
       }

}

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

( dbcp.properties的参数设置)

#old mysql version:
#driverClassName=com.mysql.jdbc.Driver
#new mysql version:
driverClassName=com.mysql.cj.jdbc.Driver
#url=jdbc:mysql://localhost:3306/users
url=jdbc:mysql://localhost:3306/users?useUnicode=true&characterEncoding=UTF-8&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=UTC&useSSL=false
username=root
password=0105
maxActive=5
initialSize=2
minIdle=2
maxWait=5000

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Exception in thread “main” java.lang.NoClassDefFoundError: org/apache/commons/logging/LogFactory
   at org.apache.commons.dbcp2.BasicDataSourceFactory.<clinit>(BasicDataSourceFactory.java:60)
   at Test_DBCP.dbcpTest.<clinit>(dbcpTest.java:31)
Caused by: java.lang.ClassNotFoundException: org.apache.commons.logging.LogFactory
   at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
   at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
   at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:349)
   at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
   … 2 more

是因为没有引入commons-logging-1.2.jar，将commons-logging-1.2.jar添加到build Path中就好了。

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