JAVA数据库连接池实现（转）

Posted 2020-08-15 THISISPAN

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连接池的管理用了了享元模式，这里对连接池进行简单设计。

一、设计思路

1.连接池配置属性DBbean：里面存放可以配置的一些属性

2.连接池接口IConnectionPool：里面定义一些基本的获取连接的一些方法

3.接口实现ConnectionPool：对上面操作进行实现，并加入一些其他方法

4.连接池管理ConnectionPoolManager：管理所有的不同的连接池，所有的连接都能通过这里进行获得连接

5.另外还有几个测试类，和连接信息模拟的类，这里就不进行xml 和配置文件信息的读取了

Java代码

package pool;
/**
* 这是外部可以配置的连接池属性
* 可以允许外部配置，拥有默认值
* @author Ran
*
*/
public class DBbean {
// 连接池属性
private String driverName;
private String url;
private String userName;
private String password;
// 连接池名字
private String poolName;
private int minConnections = 1; // 空闲池，最小连接数
private int maxConnections = 10; // 空闲池，最大连接数
private int initConnections = 5;// 初始化连接数
private long connTimeOut = 1000;// 重复获得连接的频率
private int maxActiveConnections = 100;// 最大允许的连接数，和数据库对应
private long connectionTimeOut = 1000*60*20;// 连接超时时间，默认20分钟
private boolean isCurrentConnection = true; // 是否获得当前连接，默认true
private boolean isCheakPool = true; // 是否定时检查连接池
private long lazyCheck = 1000*60*60;// 延迟多少时间后开始检查
private long periodCheck = 1000*60*60;// 检查频率
public DBbean(String driverName, String url, String userName,
String password, String poolName) {
super();
this.driverName = driverName;
this.url = url;
this.userName = userName;
this.password = password;
this.poolName = poolName;
}
public DBbean() {
}
public String getDriverName() {
if(driverName == null){
driverName = this.getDriverName()+"_"+this.getUrl();
}
return driverName;
}
public void setDriverName(String driverName) {
this.driverName = driverName;
}
public String getUrl() {
return url;
}
public void setUrl(String url) {
this.url = url;
}
public String getUserName() {
return userName;
}
public void setUserName(String userName) {
this.userName = userName;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public String getPoolName() {
return poolName;
}
public void setPoolName(String poolName) {
this.poolName = poolName;
}
public int getMinConnections() {
return minConnections;
}
public void setMinConnections(int minConnections) {
this.minConnections = minConnections;
}
public int getMaxConnections() {
return maxConnections;
}
public void setMaxConnections(int maxConnections) {
this.maxConnections = maxConnections;
}
public int getInitConnections() {
return initConnections;
}
public void setInitConnections(int initConnections) {
this.initConnections = initConnections;
}
public int getMaxActiveConnections() {
return maxActiveConnections;
}
public void setMaxActiveConnections(int maxActiveConnections) {
this.maxActiveConnections = maxActiveConnections;
}
public long getConnTimeOut() {
return connTimeOut;
}
public void setConnTimeOut(long connTimeOut) {
this.connTimeOut = connTimeOut;
}
public long getConnectionTimeOut() {
return connectionTimeOut;
}
public void setConnectionTimeOut(long connectionTimeOut) {
this.connectionTimeOut = connectionTimeOut;
}
public boolean isCurrentConnection() {
return isCurrentConnection;
}
public void setCurrentConnection(boolean isCurrentConnection) {
this.isCurrentConnection = isCurrentConnection;
}
public long getLazyCheck() {
return lazyCheck;
}
public void setLazyCheck(long lazyCheck) {
this.lazyCheck = lazyCheck;
}
public long getPeriodCheck() {
return periodCheck;
}
public void setPeriodCheck(long periodCheck) {
this.periodCheck = periodCheck;
}
public boolean isCheakPool() {
return isCheakPool;
}
public void setCheakPool(boolean isCheakPool) {
this.isCheakPool = isCheakPool;
}
}

Java代码

package pool;
import java.sql.Connection;
import java.sql.SQLException;
public interface IConnectionPool {
// 获得连接
public Connection getConnection();
// 获得当前连接
public Connection getCurrentConnecton();
// 回收连接
public void releaseConn(Connection conn) throws SQLException;
// 销毁清空
public void destroy();
// 连接池是活动状态
public boolean isActive();
// 定时器，检查连接池
public void cheackPool();
}

Java代码

package pool;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.List;
import java.util.Timer;
import java.util.TimerTask;
import java.util.Vector;
public class ConnectionPool implements IConnectionPool {
// 连接池配置属性
private DBbean dbBean;
private boolean isActive = false; // 连接池活动状态
private int contActive = 0;// 记录创建的总的连接数
// 空闲连接
private List<Connection> freeConnection = new Vector<Connection>();
// 活动连接
private List<Connection> activeConnection = new Vector<Connection>();
// 将线程和连接绑定，保证事务能统一执行
private static ThreadLocal<Connection> threadLocal = new ThreadLocal<Connection>();
public ConnectionPool(DBbean dbBean) {
super();
this.dbBean = dbBean;
init();
cheackPool();
}
// 初始化
public void init() {
try {
Class.forName(dbBean.getDriverName());
for (int i = 0; i < dbBean.getInitConnections(); i++) {
Connection conn;
conn = newConnection();
// 初始化最小连接数
if (conn != null) {
freeConnection.add(conn);
contActive++;
}
}
isActive = true;
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
}
}
// 获得当前连接
public Connection getCurrentConnecton(){
// 默认线程里面取
Connection conn = threadLocal.get();
if(!isValid(conn)){
conn = getConnection();
}
return conn;
}
// 获得连接
public synchronized Connection getConnection() {
Connection conn = null;
try {
// 判断是否超过最大连接数限制
if(contActive < this.dbBean.getMaxActiveConnections()){
if (freeConnection.size() > 0) {
conn = freeConnection.get(0);
if (conn != null) {
threadLocal.set(conn);
}
freeConnection.remove(0);
} else {
conn = newConnection();
}
}else{
// 继续获得连接,直到从新获得连接
wait(this.dbBean.getConnTimeOut());
conn = getConnection();
}
if (isValid(conn)) {
activeConnection.add(conn);
contActive ++;
}
} catch (SQLException e) {
e.printStackTrace();
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (InterruptedException e) {
e.printStackTrace();
}
return conn;
}
// 获得新连接
private synchronized Connection newConnection()
throws ClassNotFoundException, SQLException {
Connection conn = null;
if (dbBean != null) {
Class.forName(dbBean.getDriverName());
conn = DriverManager.getConnection(dbBean.getUrl(),
dbBean.getUserName(), dbBean.getPassword());
}
return conn;
}
// 释放连接
public synchronized void releaseConn(Connection conn) throws SQLException {
if (isValid(conn)&& !(freeConnection.size() > dbBean.getMaxConnections())) {
freeConnection.add(conn);
activeConnection.remove(conn);
contActive --;
threadLocal.remove();
// 唤醒所有正待等待的线程，去抢连接
notifyAll();
}
}
// 判断连接是否可用
private boolean isValid(Connection conn) {
try {
if (conn == null || conn.isClosed()) {
return false;
}
} catch (SQLException e) {
e.printStackTrace();
}
return true;
}
// 销毁连接池
public synchronized void destroy() {
for (Connection conn : freeConnection) {
try {
if (isValid(conn)) {
conn.close();
}
} catch (SQLException e) {
e.printStackTrace();
}
}
for (Connection conn : activeConnection) {
try {
if (isValid(conn)) {
conn.close();
}
} catch (SQLException e) {
e.printStackTrace();
}
}
isActive = false;
contActive = 0;
}
// 连接池状态
@Override
public boolean isActive() {
return isActive;
}
// 定时检查连接池情况
@Override
public void cheackPool() {
if(dbBean.isCheakPool()){
new Timer().schedule(new TimerTask() {
@Override
public void run() {
// 1.对线程里面的连接状态
// 2.连接池最小最大连接数
// 3.其他状态进行检查，因为这里还需要写几个线程管理的类，暂时就不添加了
System.out.println("空线池连接数："+freeConnection.size());
System.out.println("活动连接数：："+activeConnection.size());
System.out.println("总的连接数："+contActive);
}
},dbBean.getLazyCheck(),dbBean.getPeriodCheck());
}
}
}

Java代码

package pool;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.Hashtable;
/**
* 连接管理类
* @author Ran
*
*/
public class ConnectionPoolManager {
// 连接池存放
public Hashtable<String,IConnectionPool> pools = new Hashtable<String, IConnectionPool>();
// 初始化
private ConnectionPoolManager(){
init();
}
// 单例实现
public static ConnectionPoolManager getInstance(){
return Singtonle.instance;
}
private static class Singtonle {
private static ConnectionPoolManager instance = new ConnectionPoolManager();
}
// 初始化所有的连接池
public void init(){
for(int i =0;i<DBInitInfo.beans.size();i++){
DBbean bean = DBInitInfo.beans.get(i);
ConnectionPool pool = new ConnectionPool(bean);
if(pool != null){
pools.put(bean.getPoolName(), pool);
System.out.println("Info:Init connection successed ->" +bean.getPoolName());
}
}
}
// 获得连接,根据连接池名字获得连接
public Connection getConnection(String poolName){
Connection conn = null;
if(pools.size()>0 && pools.containsKey(poolName)){
conn = getPool(poolName).getConnection();
}else{
System.out.println("Error:Can‘t find this connecion pool ->"+poolName);
}
return conn;
}
// 关闭，回收连接
public void close(String poolName,Connection conn){
IConnectionPool pool = getPool(poolName);
try {
if(pool != null){
pool.releaseConn(conn);
}
} catch (SQLException e) {
System.out.println("连接池已经销毁");
e.printStackTrace();
}
}
// 清空连接池
public void destroy(String poolName){
IConnectionPool pool = getPool(poolName);
if(pool != null){
pool.destroy();
}
}
// 获得连接池
public IConnectionPool getPool(String poolName){
IConnectionPool pool = null;
if(pools.size() > 0){
pool = pools.get(poolName);
}
return pool;
}
}