數據庫連接問題；後面采用固定寫法：

解決問題

   /**c3p0取得數據源*/
    public static DataSource  getDataSource() throws Exception  {

        ComboPooledDataSource cpds = new ComboPooledDataSource();
        cpds.setDriverClass("com.mysql.jdbc.Driver");
        cpds.setJdbcUrl("jdbc:mysql://192.168.47.196:3306/test");
        cpds.setUser("root");
        cpds.setPassword("123456");

        ComboPooledDataSource datasSource = cpds;

        return datasSource;

    }
 

監聽器配置：

import java.util.Timer;
import java.util.TimerTask;
import java.util.UUID;

import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;

import cn.vote.dao.SystemDao;

public class SystemListener implements ServletContextListener {

    @Override
    public void contextInitialized(ServletContextEvent sce) {

        SystemDao systemDao = new SystemDao();
        try {
            systemDao.createTable("liwen");
            systemDao.init();
        } catch (Exception e) {

            e.printStackTrace();
        }
    }

    @Override
    public void contextDestroyed(ServletContextEvent sce) {

        try {
            SystemDao systemDao = new SystemDao();
            systemDao.dropTable("liwen");
        } catch (Exception e) {

            e.printStackTrace();
        }

    }
}
 

web.xml配置

    <listener>
        <listener-class>cn.xijie.listener.SystemListener</listener-class>           
    </listener> 

Java代碼

import java.sql.SQLException;

import org.apache.commons.dbutils.QueryRunner;

import cn.xijie.JdbcUtil.JdbcUtil;

public class SystemDao {
    //刪除表
        public void dropTable(String tableName) throws Exception{
            QueryRunner runner = new QueryRunner(JdbcUtil.getDataSource());
            String sql = "drop table if exists " + tableName;
            runner.update(sql);
        }

        //創建表
        public void createTable(String tableName) throws Exception{
            QueryRunner runner = new QueryRunner(JdbcUtil.getDataSource());
            String sql = "CREATE TABLE IF NOT EXISTS `"+tableName+"`(`runoob_id` INT UNSIGNED AUTO_INCREMENT,`runoob_title` VARCHAR(100) NOT NULL,`runoob_author` VARCHAR(40) NOT NULL,`submission_date` DATE,PRIMARY KEY ( `runoob_id` ))ENGINE=InnoDB DEFAULT CHARSET=utf8;";
            runner.update(sql);
        }

        //初始化數據
        public void init() throws Exception{
            QueryRunner runner = new QueryRunner(JdbcUtil.getDataSource());
            String sql = "INSERT INTO liwen(runoob_title, runoob_author, submission_date) VALUES (\"MySQL\", \"liwen\", NOW());";
            runner.update(sql);
        }

}
 

結果：

成功

監聽器-啟動會初始化表 學習筆記：