实现一个简单的数据库连接池
1,连接池接口
package dbsource; import java.sql.Connection; import java.sql.SQLException; /** * 连接池接口 * @author lxz * */ public interface DBSource { Connection getConnection() throws SQLException; void closeConnection(Connection con) throws SQLException; }
2,连接池实现
package dbsource; import java.io.FileInputStream; import java.io.IOException; import java.sql.Connection; import java.sql.DriverManager; import java.sql.SQLException; import java.util.ArrayList; import java.util.List; import java.util.Properties; public class BasicDBSource implements DBSource { private final static String URL = "url"; private final static String PASSWORD = "password"; private final static String USER = "user"; private final static String POOLMAX = "poolmax"; private final static String DRIVER = "driver"; private final static String INIT = "init"; private final static String DEFAULT_PRO = "myjdbc.properties"; private Properties pro = new Properties();// 属性文件对象 private String url;// 地址 private String user;// 数据库用户名 private String password;// 数据库密码 private int max;// 最大连接数 private int init;//初始化连接池 private List<Connection> connections;// 数据连接集合 public BasicDBSource(String configFile) throws IOException, ClassNotFoundException { pro.load(new FileInputStream(configFile)); url = pro.getProperty(URL); user = pro.getProperty(USER); password = pro.getProperty(PASSWORD); max = Integer.parseInt(pro.getProperty(POOLMAX)); init = Integer.parseInt(pro.getProperty(INIT)); Class.forName(pro.getProperty(DRIVER)); connections = new ArrayList<Connection>(); for(int i=0;i<init;i++){ try { connections.add(DriverManager.getConnection(url,user,password)); } catch (SQLException e) { //数据库连接失败 } } } public BasicDBSource() throws ClassNotFoundException, IOException{ this(DEFAULT_PRO); } public Connection getConnection() throws SQLException { if(connections.size()==0){ return DriverManager.getConnection(url,user,password); }else{ int last = connections.size()-1; return connections.remove(last); } } public void closeConnection(Connection con) throws SQLException { if(connections.size()>=max){ con.close(); }else{ connections.add(con); } } }
3,配置文件
url=数据库地址 password=密码 user=用户名 poolmax=最大连接数 driver=数据库驱动 init=初始化连接数
4,测试
package source; import java.io.IOException; import java.sql.Connection; import java.sql.SQLException; import dbsource.BasicDBSource; import dbsource.DBSource; public class MainTest { public static void main(String[] args) { try { DBSource dbsource = new BasicDBSource("myjdbc.properties"); Connection con1 = dbsource.getConnection(); System.out.println("第一次获取的数据库连接对象地址:"+con1); dbsource.closeConnection(con1); Connection con2 = dbsource.getConnection(); System.out.println("第二次获取的数据库连接对象地址:"+con2); } catch (ClassNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } catch (SQLException e) { e.printStackTrace(); } } }