package com.abin.lee.collection.pool;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.LinkedList;
import java.util.List;
public class ConnectionManage {
private static List<Connection> pool=new LinkedList<Connection>();;
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 static int initCount = 5;
private static int maxCount = 10;
private static int currentCount = 5;
private static volatile ConnectionManage instance = null;
private ConnectionManage(){
init();
}
public static ConnectionManage getInstance(){
if(null == instance){
synchronized (ConnectionManage.class) {
if(null == instance){
return new ConnectionManage();
}
}
}
return instance;
}
public void init(){
addConnection();
}
public static Connection createConnection() throws ClassNotFoundException {
Connection conn=null;
try {
Class.forName(DRIVER);
conn=DriverManager.getConnection(Url, USERNAME, PASSWORD);
} catch (SQLException e) {
e.printStackTrace();
}
return conn;
}
public static void addConnection(){
for(int i=0;i<initCount;i++){
try {
pool.add(createConnection());
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
}
}
public static void release(Connection conn){
pool.add(conn);
}
public static Connection getConnection() throws SQLException, ClassNotFoundException{
synchronized (pool) {
if(pool.size()>0){
System.out.println("Current Connection size is:"+pool.size());
return pool.get(0);
}else if(currentCount<maxCount){
Class.forName(DRIVER);
Connection conn=createConnection();
pool.add(conn);
currentCount++;
return conn;
}else{
throw new SQLException("Current Connection is Zero");
}
}
}
}
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=ConnectionManage.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());
}
}
}