jdbc連接池配置方法

代碼：import java.io.FileInputStream;import java.io.FileNotFoundException;

import java.io.IOException; import java.io.InputStream; import java.io.PrintWriter; import java.lang.reflect.InvocationHandler; import java.lang.reflect.Method; import java.lang.reflect.Proxy; import java.sql.Connection; import java.sql.DriverManager; import java.sql.SQLException; import java.sql.SQLFeatureNotSupportedException; import java.util.LinkedList; import java.util.Properties; import org.slf4j.Logger; public class ConnPool { // 使用LinkedList集合存放數據庫連接 private static LinkedList<Connection> connPool = new LinkedList<Connection>(); // 在靜態代碼塊中加載配置文件 static {
　　　　　//如果以jar包運行，此處會報找不到這個文件的異常，解決方案如下。 String path = ConnPool.class.getClassLoader().getResource("db.properties").getPath();//解決方案需要注釋這行代碼
　　　　　//InputStream in = PropertiesUtil.class.getClassLoader.getResourceAsStream("db.properties");//開啟這行代碼解決以上問題
 FileInputStream in;//開啟以上解決方案需要注釋調這行代碼 try { in = new FileInputStream(path);//開啟以上解決方案需要注釋這行代碼 Properties prop = new Properties(); prop.load(in); String driver = prop.getProperty("driver"); String url = prop.getProperty("url"); String user = prop.getProperty("user"); String password = prop.getProperty("password"); // 數據庫連接池的初始化連接數的大小 int InitSize = Integer.parseInt(prop.getProperty("InitSize")); // 加載驅動  Class.forName(driver); for (int i = 0; i < InitSize; i++) { Connection conn = DriverManager.getConnection(url, user, password); // 將創建的連接添加的list中 System.out.println("初始化數據庫連接池，創建第 " + (i + 1) + " 個連接，添加到池中"); connPool.add(conn); } } catch (IOException e) { e.printStackTrace(); } catch (ClassNotFoundException e) { e.printStackTrace(); } catch (SQLException e) { e.printStackTrace(); } } /*獲取數據庫連接*/ public Connection getConnection() throws SQLException { if(connPool.size() > 0){ //從集合中獲取一個連接 final Connection conn = connPool.removeFirst(); //返回Connection的代理對象 return (Connection) Proxy.newProxyInstance(ConnPool.class.getClassLoader(), conn.getClass().getInterfaces(), new InvocationHandler() { public Object invoke(Object proxy, Method method, Object[] args) throws Throwable { if(!"close".equals(method.getName())){ return method.invoke(conn, args); }else{ connPool.add(conn); System.out.println("關閉當前連接，把連接還給連接池........."); System.out.println("池中連接數為 " + connPool.size()); return null; } } }); }else{ throw new RuntimeException("數據庫繁忙，稍后再試............"); } } public PrintWriter getLogWriter() throws SQLException { return null; } public void setLogWriter(PrintWriter out) throws SQLException { } public void setLoginTimeout(int seconds) throws SQLException { } public int getLoginTimeout() throws SQLException { return 0; } public Logger getParentLogger() throws SQLFeatureNotSupportedException { return null; } public Object unwrap(Class iface) throws SQLException { return null; } public boolean isWrapperFor(Class iface) throws SQLException { return false; } public Connection getConnection(String username, String password) throws SQLException { return null; } }

import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class JdbcUtil {

    //數據庫連接池
    private static ConnPool  connPool = new ConnPool();

    /**
     * 從池中獲取一個連接
     * @return
     * @throws SQLException
     */
    public static Connection getConnection() throws SQLException{
        return connPool.getConnection();
    }

    /**
     * 關閉連接
     * @param conn
     * @param st
     * @param rs
     * @throws SQLException 
     */
    public static void CloseConnection(Connection conn, Statement st, ResultSet rs) throws SQLException{

        // 關閉存儲查詢結果的ResultSet對象
        if(rs != null){
                rs.close();
        }

        //關閉Statement對象
        if(st != null){
                st.close();
        }

        //關閉連接
        if(conn != null){
                conn.close();
        }
    }

}

db.properties

driver = com.mysql.cj.jdbc.Driver
url = jdbc:mysql://localhost:3306/數據庫名?serverTimezone=Asia/Shanghai&useUnicode=true&characterEncoding=utf8&useSSL=TRUE
user = root
password = root
InitSize = 15

調用如下：

JdbcUtil jdbcUtil = new JdbcUtil();

　　String sql = "要寫的SQL語句"; 　　Connection connection = null; 　　Statement statement = null; 　　ResultSet resultSet = null;

try{
　　connection = jdbcUtil.getConnection();
　　statement = connection.createStatement();
　　resultSet = statement.executeQuery(sql);
　　　　while (resultSet.next()) {
    　　　　String id= resultSet.getString("id");
    　　　　if (id!= null) {
　　　　　　//可以在這里寫業務邏輯
　　　　　　}
　　　　}
　　} catch (Exception e) {
            logger.error("數據獲取失敗", e);
            msg = createResultJson(1, "數據獲取失敗！");
   } finally {
     try {
       　　jdbcUtil.CloseConnection(connection, statement, resultSet);//最后記得關閉流，不然會報創建連接過多的異常
     } catch (SQLException e) {
     // TODO Auto-generated catch block
     e.printStackTrace();
     }
   }