文章目录 享元模式 1.引出享元模式 2.享元模式 1.基本介绍 2.原理类图 3.外部状态和内部状态 4.类图 5.代码实现 1.AbsWebSite.java 抽象的网站 2.ConcreteWebSite.java 具体的网站，type属性是内部状态 3.WebSiteFactory.java 网站工厂，根据类型，获取对应类型的网站 4.User.java 使用网站的用户，是外部状态 5.Client.java 6.结果 6.小结 3.享元模式在Integer的应用 代理模式 1.基本介绍 2.静态代理 1.基本介绍 2.类图 3.代码实现 1.目录结构 2.ITeacherDao.java 被代理的接口 3.TeacherDao.java 被代理的实现类 4.TeacherDaoProxy.java 静态代理类 5.Client.java 6.结果 2.动态代理（JDK代理） 1.基本介绍 2.类图 3.代码实现 1.ITeacherDao.java 被代理的接口 2.TeacherDao.java 被代理的类 3.ProxyFactory.java 代理工厂，返回动态代理对象 4.Client.java 5.结果 3.Cglib代理 1.基本介绍 2.注意事项 3.类图 4.引入四个jar包 5.代码实现 1.目录结构 2.TeacherDao.java 被代理的类 3.ProxyFactory.java 返回代理对象的工厂 4.Client.java 5.结果 6.几种变体
package com. sun ;
public abstract class AbsWebSite { public abstract void use ( User user) ;
}
package com. sun ;
public class ConcreteWebSite extends AbsWebSite { private String type = "" ; public ConcreteWebSite ( String type) { this . type = type; } @Override public void use ( User user) { System . out. println ( "网站的发布类型为：" + type + user. getName ( ) + "在使用中" ) ; }
}
package com. sun ; import java. util. HashMap ;
public class WebSiteFactory { private HashMap < String , ConcreteWebSite > = new HashMap < > ( ) ; public AbsWebSite getWebsiteCategory ( String type) { if ( ! pool. containsKey ( type) ) { pool. put ( type, new ConcreteWebSite ( type) ) ; } return ( AbsWebSite ) pool. get ( type) ; } public int getWebSiteCount ( ) { return pool. size ( ) ; }
}
package com. sun ;
public class User { private String name; public User ( String name) { this . name = name; } public String getName ( ) { return name; } public void setName ( String name) { this . name = name; }
}
package com. sun ;
public class Client { public static void main ( String [ ] args) { WebSiteFactory webSiteFactory = new WebSiteFactory ( ) ; AbsWebSite webSite = webSiteFactory. getWebsiteCategory ( "新闻" ) ; webSite. use ( new User ( "tom" ) ) ; AbsWebSite webSite2 = webSiteFactory. getWebsiteCategory ( "博客" ) ; webSite2. use ( new User ( "jack" ) ) ; AbsWebSite webSite3 = webSiteFactory. getWebsiteCategory ( "博客" ) ; webSite3. use ( new User ( "lisa" ) ) ; AbsWebSite webSite4 = webSiteFactory. getWebsiteCategory ( "博客" ) ; webSite4. use ( new User ( "milan" ) ) ; int webSiteCount = webSiteFactory. getWebSiteCount ( ) ; System . out. println ( "webSiteCount = " + webSiteCount) ; }
}
package com. sun. staticproxy ;
public interface ITeacherDao { void teach ( ) ;
}
package com. sun. staticproxy ;
public class TeacherDao implements ITeacherDao { @Override public void teach ( ) { System . out. println ( "老师正在授课中" ) ; }
}
package com. sun. staticproxy ;
public class TeacherDaoProxy implements ITeacherDao { private ITeacherDao teacherDao; public TeacherDaoProxy ( ITeacherDao teacherDao) { this . teacherDao = teacherDao; } @Override public void teach ( ) { System . out. println ( "代理开始" ) ; teacherDao. teach ( ) ; System . out. println ( "代理结束" ) ; }
}
package com. sun. staticproxy ;
public class Client { public static void main ( String [ ] args) { TeacherDaoProxy teacherDaoProxy = new TeacherDaoProxy ( new TeacherDao ( ) ) ; teacherDaoProxy. teach ( ) ; }
}
package com. sun. dynamic ;
public interface ITeacherDao { void teach ( String name) ; }
package com. sun. dynamic ;
public class TeacherDao implements ITeacherDao { @Override public void teach ( String name) { System . out. println ( name + "老师正在授课中" ) ; } }
package com. sun. dynamic ; import java. lang. reflect. InvocationHandler ;
import java. lang. reflect. Method ;
import java. lang. reflect. Proxy ;
import java. util. Arrays ;
public class ProxyFactory { private Object target; public ProxyFactory ( Object target) { this . target = target; } public Object getProxyInstance ( ) { return Proxy . newProxyInstance ( target. getClass ( ) . getClassLoader ( ) , target. getClass ( ) . getInterfaces ( ) , new InvocationHandler ( ) { @Override public Object invoke ( Object proxy, Method method, Object [ ] args) throws Throwable { System . out. println ( "method = " + method + ", args = " + Arrays . toString ( args) ) ; System . out. println ( "动态代理开始" ) ; Object result = method. invoke ( target, args) ; System . out. println ( "动态代理结束" ) ; return result; } } ) ; }
}
package com. sun. dynamic ;
public class Client { public static void main ( String [ ] args) { ITeacherDao target = new TeacherDao ( ) ; ITeacherDao proxy = ( ITeacherDao ) new ProxyFactory ( target) . getProxyInstance ( ) ; proxy. teach ( "李华" ) ; }
}
package com. sun. cglib ;
public class TeacherDao { public void teach ( String name) { System . out. println ( name + "老师授课中，使用的是cglib代理，不需要实现接口" ) ; }
}
package com. sun. cglib ; import net. sf. cglib. proxy. Enhancer ;
import net. sf. cglib. proxy. MethodInterceptor ;
import net. sf. cglib. proxy. MethodProxy ; import java. lang. reflect. Method ;
public class ProxyFactory implements MethodInterceptor { private Object target; public ProxyFactory ( Object target) { this . target = target; } public Object getProxyInstance ( ) { Enhancer enhancer = new Enhancer ( ) ; enhancer. setSuperclass ( target. getClass ( ) ) ; enhancer. setCallback ( this ) ; return enhancer. create ( ) ; } @Override public Object intercept ( Object o, Method method, Object [ ] args, MethodProxy methodProxy) throws Throwable { System . out. println ( "cglib代理模式开始" ) ; System . out. println ( "method = " + method) ; System . out. println ( "args = " + args) ; Object returnVal = method. invoke ( target, args) ; System . out. println ( "cglib代理结束" ) ; return returnVal; }
}
package com. sun. cglib ;
public class Client { public static void main ( String [ ] args) { TeacherDao teacherDao = new TeacherDao ( ) ; ProxyFactory proxyFactory = new ProxyFactory ( teacherDao) ; TeacherDao proxyInstance = ( TeacherDao ) proxyFactory. getProxyInstance ( ) ; proxyInstance. teach ( "小明" ) ; }
}
