在项目中集成druid数据库连接池

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1.下载相关jar：druid-1.1.9.jar 和 mysql-connector-java-5.1.38.jar  。

2.将jar导入项目。并且并且配置build path。具体可以参考 jetty嵌入式开发hello world

3.创建util包里的DBPoolConnection类。

package application.util;


import java.io.File;
import java.io.FileInputStream;
import java.io.InputStream;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import java.util.Properties;

import com.alibaba.druid.pool.DruidDataSource;
import com.alibaba.druid.pool.DruidDataSourceFactory;
import com.alibaba.druid.pool.DruidPooledConnection;

/**
 * 要实现单例模式，保证全局只有一个数据库连接池
 * @author pelin
 *
 * 2018年03月23日
 */
public class DBPoolConnection {
    private static DBPoolConnection dbPoolConnection = null;
    private static DruidDataSource druidDataSource = null;
    
    static {
    	Properties properties = loadPropertiesFile("config\\db_server.properties");
        try {
            druidDataSource = (DruidDataSource)DruidDataSourceFactory.createDataSource(properties);    //DruidDataSrouce工厂模式
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    
    /**
     * 数据库连接池单例
     * @return
     */
    public static synchronized DBPoolConnection getInstance(){
        if (null == dbPoolConnection){
            dbPoolConnection = new DBPoolConnection();
        }
        return dbPoolConnection;
    }
    
    /**
     * 返回druid数据库连接
     * @return
     * @throws SQLException
     */
    public DruidPooledConnection getConnection() throws SQLException{
        return druidDataSource.getConnection();
    }
    /**
     * @param string 配置文件名
     * @return Properties对象
     */
    private static Properties loadPropertiesFile(String fullFile) {
        String webRootPath = PathUtil.projectPath;
        if (null == fullFile || fullFile.equals("")){
            throw new IllegalArgumentException("Properties file path can not be null" + fullFile);
        }
        InputStream inputStream = null;
        Properties p = null;
        try {
            inputStream = new FileInputStream(new File(webRootPath + "\\" + fullFile));
            p = new Properties();
            p.load(inputStream);
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                if (null != inputStream){
                    inputStream.close();
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return p;
    }
    
    
    public static void main(String[] args) {
    	//执行一条sql语句测试
    	DBPoolConnection dbp = DBPoolConnection.getInstance();    //获取数据连接池单例
        DruidPooledConnection conn = null;
        PreparedStatement ps = null;
        try {
        	String sql = "update sys_user set name='tbuser'  where id=2;";
            conn = dbp.getConnection();    //从数据库连接池中获取数据库连接
            ps = conn.prepareStatement(sql);
            ps.executeUpdate();
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            try {
                if (null != ps){
                    ps.close();
                }
                if (null != conn){
                    conn.close();
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
	}
}

4.创建数据库连接配置文件db_server.properties

driverClassName=com.mysql.jdbc.Driver
url=jdbc:mysql://127.0.0.1:3306/test
username=root
password=123456
filters=stat
initialSize=2
maxActive=300
maxWait=60000
timeBetweenEvictionRunsMillis=60000
minEvictableIdleTimeMillis=300000
validationQuery=SELECT 1
testWhileIdle=true
testOnBorrow=false
testOnReturn=false
poolPreparedStatements=false

maxPoolPreparedStatementPerConnectionSize=200

最后运行DBPoolConnection类里面的main方法测试。

目录结构：