package com.abin.lee.collection.pool;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
public class ConnectionPool {
private List<Connection> pool;
private static final String Url = "jdbc:oracle:thin:@localhost:1521:XE";
private static final String USERNAME = "abing";
private static final String PASSWORD = "abing";
private static final String DRIVER = "oracle.jdbc.driver.OracleDriver";
private int poolSize = 10;
private static volatile ConnectionPool instance = null;
private ConnectionPool() {
init();
}
public void init() {
pool = new ArrayList<Connection>(poolSize);
addConnection();
}
public synchronized void release(Connection conn) {
pool.add(conn);
}
public synchronized void closePool() {
for (int i = 0; i < pool.size(); i++) {
try {
((Connection) pool.get(i)).close();
} catch (SQLException e) {
e.printStackTrace();
}
pool.remove(i);
}
}
public static ConnectionPool getInstance() {
if (null == instance) {
synchronized (ConnectionPool.class) {
if (null == instance) {
return new ConnectionPool();
}
}
}
return instance;
}
public synchronized Connection getConnection() {
if (pool.size() > 0) {
Connection conn = pool.get(0);
if(conn!=null){
System.out.println("Connection Pool Create Success");
}
pool.remove(conn);
return conn;
}else{
return null;
}
}
public void addConnection() {
Connection conn = null;
for (int i = 0; i < poolSize; i++) {
try {
Class.forName(DRIVER);
conn = DriverManager.getConnection(Url, USERNAME, PASSWORD);
pool.add(conn);
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
测试代码：
package com.abin.lee.collection.pool;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;
import com.abin.lee.collection.threadlocal.UserBean;
public class TestConnectionPool {
public static List<UserBean> findAll(){
Connection conn=null;
PreparedStatement ps=null;
ResultSet rs=null;
String sql="select * from userbean order by id desc";
List<UserBean> list=new ArrayList<UserBean>();
UserBean user=null;
try {
conn=ConnectionPool.getInstance().getConnection();
ps=conn.prepareStatement(sql);
rs=ps.executeQuery();
while (rs.next()&&rs!=null) {
user=new UserBean();
user.setId(rs.getString("id"));
user.setUsername(rs.getString("username"));
user.setPassword(rs.getString("password"));
list.add(user);
}
} catch (Exception e) {
e.printStackTrace();
}
return list;
}
public static void main(String[] args) {
List<UserBean> list=findAll();
for(UserBean lst:list){
System.out.println("id="+lst.getId());
System.out.println("username="+lst.getUsername());
System.out.println("id="+lst.getPassword());
}
}
}