这是我实现的ConnectionPool。将所有变量和方法都设置为静态是一种好的设计。请解释原因或原因
public class MyCp1 {
private static final int MAX_SIZE=100;
private static final BlockingQueue<Connection> bq;
static{
System.out.println("Inside begin static block" );
bq= new ArrayBlockingQueue<Connection>(MAX_SIZE);
for(int i=0;i<MAX_SIZE;i++)
{
try {
try {
bq.put(makeConnection());
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
System.out.println("total size:" + bq.size());
}
public static Connection getConnection() throws InterruptedException
{
System.out.println("size before getting connection "+ bq.size()+ " Thread name "+ Thread.currentThread().getName());
Connection con=bq.take();
System.out.println("size after getting connection "+ bq.size()+" Thread name "+ Thread.currentThread().getName());
return (con);
}
public static boolean releaseConnection(Connection con) throws InterruptedException
{
System.out.println("size before releasing connection "+ bq.size()+" Thread name "+ Thread.currentThread().getName());
boolean bool =bq.add(con);
System.out.println("size after releasing connection "+ bq.size()+" Thread name "+ Thread.currentThread().getName());
return (bool);
}
public static Connection makeConnection() throws SQLException {
Connection conn = null;
Properties connectionProps = new Properties();
connectionProps.put("user", "root");
connectionProps.put("password", "java33");
try {
Class.forName("com.mysql.jdbc.Driver");
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
conn = DriverManager.getConnection("jdbc:" + "mysql" + "://"
+ "localhost" + ":" + "3306" + "/test", connectionProps);
System.out.println("Connected to database");
return conn;
}
}
我知道有特殊处理和其他问题,但如果你能坚持上述问题,我将不胜感激
EDIT ::
看起来使用静态不受青睐。所以我尽可能地重构以摆脱静态。虽然这有效,但不确定这是否是好的设计
public class ConnectionPool {
private static final int MAX_SIZE = 100;
private BlockingQueue<Connection> bq;
private static ConnectionPool cp= new ConnectionPool();
private ConnectionPool(){
System.out.println("inside constructor");
bq = new ArrayBlockingQueue<Connection>(MAX_SIZE);
Properties connectionProps = new Properties();
connectionProps.put("user", "root");
connectionProps.put("password", "java33");
try {
Class.forName("com.mysql.jdbc.Driver");
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
for (int i = 0; i < MAX_SIZE; i++) {
try {
bq.put(makeConnection(connectionProps));
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
System.out.println("total size:" + bq.size());
}
public static ConnectionPool getInstance()
{
return cp;
}
public Connection getConnection() throws InterruptedException {
System.out.println("size before getting connection" + bq.size());
Connection con = bq.take();
System.out.println("size after getting connection" + bq.size());
return (con);
}
public void releaseConnection(Connection con)
throws InterruptedException {
System.out.println("size before releasing connection" + bq.size());
bq.put(con);
System.out.println("size after releasing connection" + bq.size());
//return (bool);
}
private Connection makeConnection(Properties connectionProps) throws SQLException {
Connection conn = null;
conn = DriverManager.getConnection("jdbc:" + "mysql" + "://"
+ "localhost" + ":" + "3306" + "/test", connectionProps);
System.out.println("Connected to database");
return conn;
}
}
答案 0 :(得分:2)
绝对不是。你拥有的更多的是一个对象回收器,如果这就是你需要的那么就好了。
(作为回收商,你仍然不想要静态字段,但你只需要创建一个回收器实例。)
对于连接池(如果是JDBC连接),它需要是线程安全的,理想情况下你不需要返回连接。
线程安全的连接池将使用ThreadLocal返回仅在该线程上使用的连接。如果没有,则会通过实施ThreadLocal.initialValue()来创建新连接。
此外,您的线程应使用ExecutorService创建,因此您也可以重用线程。