basicdbsource.java

来自「有关java学习技巧的课件」· Java 代码 · 共 55 行

package onlyfun.caterpillar;

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 Properties props;
    private String url;
    private String user;
    private String passwd;
    private int max; // 连接池中最大Connection数目
    private List<Connection> connections;

    public BasicDBSource() throws IOException, ClassNotFoundException {
        this("jdbc.properties");
    }
    
    public BasicDBSource(String configFile) throws IOException, ClassNotFoundException {
        props = new Properties();
        props.load(new FileInputStream(configFile));
        
        url = props.getProperty("onlyfun.caterpillar.url");
        user = props.getProperty("onlyfun.caterpillar.user");
        passwd = props.getProperty("onlyfun.caterpillar.password");
        max = Integer.parseInt(props.getProperty("onlyfun.caterpillar.poolmax"));
        Class.forName(props.getProperty("onlyfun.caterpillar.driver"));
        
        connections = new ArrayList<Connection>();
    }

    public synchronized Connection getConnection() throws SQLException {
        if(connections.size() == 0) {
            return DriverManager.getConnection(url, user, passwd);
        }
        else {
            int lastIndex = connections.size() - 1;
            return connections.remove(lastIndex);
        }
    }
    
    public synchronized void closeConnection(Connection conn) throws SQLException {
        if(connections.size() == max) {
            conn.close();
        }
        else {
            connections.add(conn);
        }
    }
}