Java复习之知识点整理（二十九）---MySQL池化设计模式，自定义池，第三方开源池 c3p0,dbcp
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一、池化设计模式
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1.使用有限的对象去服务于大量的客户端
二、使用第三方开元的连接池实现
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1.c3p0
/**
* 测试c3p0连接池
*/
public static void tsC3P0()
{
try {
//创建连接池
ComboPooledDataSource ds = new ComboPooledDataSource();
//加载驱动
ds.setDriverClass("com.mysql.jdbc.Driver");
//设定url
ds.setJdbcUrl("jdbc:mysql://localhost:3306/mydata");
//
ds.setUser("mysql");
ds.setPassword("mysql");
ds.setMaxPoolSize(10); //池子最大连接数
ds.setMinPoolSize(2); //池子最小连接数
ds.setInitialPoolSize(3); //池子初始化连接数
ds.setAcquireIncrement(2); //每次增加2个连接
//
Connection conn = ds.getConnection();
PreparedStatement pt = conn.prepareStatement("insert into customers (name) values('v1')");
pt.executeUpdate();
pt.close();
conn.close();
} catch (Exception e) {
e.printStackTrace();
}
}
2.DBCP
/**
* 测试dbcp连接池
*/
public static void tsDBCP()
{
try {
//创建连接池
BasicDataSource ds = new BasicDataSource();
//加载驱动
ds.setDriverClassName("com.mysql.jdbc.Driver");
//设定url
ds.setUrl("jdbc:mysql://localhost:3306/mydata");
//
ds.setUsername("mysql");
ds.setPassword("mysql");
ds.setMaxTotal(10); //池子最大连接数
ds.setInitialSize(3); //池子初始化连接数
//
Connection conn = ds.getConnection();
PreparedStatement pt = conn.prepareStatement("insert into customers (name) values('v2')");
pt.executeUpdate();
pt.close();
conn.close();
} catch (Exception e) {
e.printStackTrace();
}
}
三、自定义连接池
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1.类结构图
2.代码区
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*******Part1.TsMain 测试主函数
------------------------------------------------------------
/**
* 测试自定义数据源
*/
public class TsMain {
public static void main(String[] args) {
try {
MyDataSource dt = new MyDataSource();
//1.
Connection conn = dt.getConnection();
PreparedStatement pt = conn.prepareStatement("insert into customers (name) values('xxx1')");
pt.executeUpdate();
pt.close();
conn.close();
//2.
conn = dt.getConnection();
pt = conn.prepareStatement("insert into customers (name) values('xxx2')");
pt.executeUpdate();
pt.close();
conn.close();
//3.
conn = dt.getConnection();
pt = conn.prepareStatement("insert into customers (name) values('xxx3')");
pt.executeUpdate();
pt.close();
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
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*******Part2.TsMain 自定义数据源
------------------------------------------------------------
/**
* 自定义数据源
*/
public class MyDataSource implements DataSource{
//连接池
private ConnectionPool pool;
public MyDataSource()
{
String driver = "com.mysql.jdbc.Driver";
String url = "jdbc:mysql://localhost:3306/mydata";
String user = "mysql";
String password = "mysql";
pool = new ConnectionPool(driver, url, user, password);
pool.init();
}
@Override
public PrintWriter getLogWriter() throws SQLException {
return null;
}
@Override
public void setLogWriter(PrintWriter out) throws SQLException {
}
@Override
public void setLoginTimeout(int seconds) throws SQLException {
}
@Override
public int getLoginTimeout() throws SQLException {
return 0;
}
@Override
public Logger getParentLogger() throws SQLFeatureNotSupportedException {
return null;
}
@Override
public <T> T unwrap(Class<T> iface) throws SQLException {
return null;
}
@Override
public boolean isWrapperFor(Class<?> iface) throws SQLException {
return false;
}
/**
* 获取连接
*/
public Connection getConnection() throws SQLException {
return pool.getConn();
}
@Override
public Connection getConnection(String username, String password)
throws SQLException {
return null;
}
}
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*******Part3.TsMain 自定义连接池
------------------------------------------------------------
/**
* 连接池
*/
public class ConnectionPool {
//最大连接数
private int max = 2;
//连接的集合
private List<Connection> connections = new ArrayList<Connection>();
//连接驱动
private String driver;
//数据库url
private String url;
private String user;
private String password;
public ConnectionPool(String driver, String url, String user,
String password) {
this.driver = driver;
this.url = url;
this.user = user;
this.password = password;
//加载驱动
try {
Class.forName(driver);
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
//初始化连接池
public void init()
{
for(int i = 0 ; i < max ; i ++)
{
try {
//获取连接
Connection conn = DriverManager.getConnection(url, user, password);
MyConnection myConn = new MyConnection(conn, this);
connections.add(myConn);
} catch (Exception e) {
e.printStackTrace();
}
}
}
/**
* 回收连接
* @param conn 回收的连接
*/
public void recyleConn(MyConnection conn) {
connections.add(conn);
}
/**
* 释放连接
*/
public Connection getConn()
{
if(connections.isEmpty())
{
System.out.println("pool is empty");
return null;
}
else
{
return connections.remove(0);
}
}
}
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*******Part4.ConnectionAdapter 连接的适配器（适配器模式）
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/**
* 连接适配器
*/
public abstract class ConnectionAdapter implements Connection{
//注：此处方法太多，不贴了
//只要引用接口Connection，并实现其方法即可
}
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*******Part5.自定义连接类（装饰模式）
******主要在于重写getConnectio()方法
------------------------------------------------------------
/**
* 自定义数据源
*/
public class MyDataSource implements DataSource{
//连接池
private ConnectionPool pool;
public MyDataSource()
{
String driver = "com.mysql.jdbc.Driver";
String url = "jdbc:mysql://localhost:3306/mydata";
String user = "mysql";
String password = "mysql";
pool = new ConnectionPool(driver, url, user, password);
pool.init();
}
@Override
public PrintWriter getLogWriter() throws SQLException {
return null;
}
@Override
public void setLogWriter(PrintWriter out) throws SQLException {
}
@Override
public void setLoginTimeout(int seconds) throws SQLException {
}
@Override
public int getLoginTimeout() throws SQLException {
return 0;
}
@Override
public Logger getParentLogger() throws SQLFeatureNotSupportedException {
return null;
}
@Override
public <T> T unwrap(Class<T> iface) throws SQLException {
return null;
}
@Override
public boolean isWrapperFor(Class<?> iface) throws SQLException {
return false;
}
/**
* 获取连接
*/
public Connection getConnection() throws SQLException {
return pool.getConn();
}
@Override
public Connection getConnection(String username, String password)
throws SQLException {
return null;
}
}
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