说到连接池，最常见的就是dbcp和c3p0，关于druid，官方定义是为监控而生的数据库连接池。

官方中文文档地址：

下面我介绍如何在servlet即不使用任何框架的时刻下使用druid并显示监控页面。

 

连接池之间的性能测试

 

 

1、首先导入下面这2个jar包

链接：https://pan.baidu.com/s/1e9lLS3e0xFdUFsPTu9rSQA 密码：xj6v

 

 

2、在web.xml文件中加入如下配置：

             
      
       druidWebStatFilter
              
      
       com.alibaba.druid.support.http.WebStatFilter
              
                  
       
        exclusions
                   
       
        /public/*,*.js,*.css,/druid*,*.jsp,*.swf
               
          
         
             
      
       druidWebStatFilter
              
      
       /*
          
         
             
      
       DruidStatView
              
      
       com.alibaba.druid.support.http.StatViewServlet
              
                  
       
        allow
                   
       
        127.0.0.1
               
          
         
             
      
       DruidStatView
              
      
       /druid/*
          
     

 

3、在src下建一个db_server.properties的配置文件

内容如下，可根据自身需求调整

driverClassName=com.mysql.jdbc.Driverurl=jdbc:mysql:///kaoqin?useSSL=trueusername=rootpassword=rootfilters=statinitialSize=2maxActive=300maxWait=60000timeBetweenEvictionRunsMillis=60000minEvictableIdleTimeMillis=300000validationQuery=SELECT 1testWhileIdle=truetestOnBorrow=falsetestOnReturn=falsepoolPreparedStatements=falsemaxPoolPreparedStatementPerConnectionSize=200

 

4、创建一个DruidConnection类

public class DruidConnection {    private static Properties properties = null;    private static DataSource dataSource = null;    private volatile static DruidConnection instatce = null;    private Connection connection = null;    //私有构造函数,防止实例化对象    private DruidConnection() {    }    static {        try {            properties = new Properties();            // 1.加载properties文件            InputStream is = DruidConnection.class.getClassLoader().getResourceAsStream("db_server.properties");            // 2.加载输入流            properties.load(is);            // 3.获取数据源            dataSource = getDatasource();        } catch (IOException e) {            e.printStackTrace();        }    }    /**     * 用简单单例模式确保只返回一个链接对象     *      * @return     */    public static  DruidConnection getInstace() {        if(instatce == null) {            synchronized (DruidConnection.class) {                if(instatce == null) {                    instatce = new DruidConnection();                }            }        }        return instatce;    }    // 返回一个数据源    public DataSource getDataSource() {        return dataSource;    }    // 返回一个链接    public Connection getConnection() {        try {            connection = dataSource.getConnection();        } catch (SQLException e) {            e.printStackTrace();        }        return connection;    }    // 加载数据源    private static DataSource getDatasource() {        DataSource source = null;        try {            source = DruidDataSourceFactory.createDataSource(properties);        } catch (Exception e) {            e.printStackTrace();        }        return source;    }}

 

5、创建工具类DruidUtils

public class DruidUtils {    private static Connection connection = null;    //获取元数据    public static DataSource getDatasource() {        DataSource dataSource = DruidConnection.getInstace().getDataSource();        return dataSource;    }    //获取链接    public static Connection getConnection() {         connection = DruidConnection.getInstace().getConnection();        return connection;    }    //归还资源    public void release() {        try {            if(connection != null) {                connection.close();            }        } catch (SQLException e) {            e.printStackTrace();        }    }}

 

6、在DAO层应用（举例）

public class UserDao {    public User login(String name,String password) throws SQLException {        // TODO Auto-generated method stub        QueryRunner runner = new QueryRunner(DruidUtils.getDatasource());        String sql = "select * from user where name=? and password=?";        User user = runner.query(sql, new BeanHandler
     
      (User.class), name, password);        return user;    }}
     

 

7、浏览地址：${pageContext.request.contextPath}/druid/index.html

效果图：