注：今天看《Effective Java 中文版 第2版》時(shí)，發(fā)現(xiàn)在靜態(tài)工廠方法中提到的服務(wù)提供者框架的簡(jiǎn)單實(shí)現(xiàn)代碼不夠完整，所以自己寫了一份完整代碼附帶一些解釋，希望對(duì)大家有所幫助。

Service.java

// 服務(wù)接口public interface Service {    public abstract void serve();}

PRovider.java

// 提供者接口public interface Provider {    Service newService();}

ServiceManager.java

import java.util.Map;import java.util.concurrent.ConcurrentHashMap;public class ServiceManager {    private ServiceManager() {}        // 把服務(wù)接口的名字映射到Services中    private static final Map<String, Provider> providers =             new ConcurrentHashMap<String, Provider>();    public static final String DEFAULT_PROVIDER_NAME = "<def>";        // 提供者注冊(cè)API(默認(rèn))    public static void registerDefaultProvider(Provider p) {        registerProvider(DEFAULT_PROVIDER_NAME, p);    }

    // 提供者注冊(cè)API    public static void registerProvider(String name, Provider p) {        providers.put(name, p);    }        // 服務(wù)訪問API(默認(rèn))    public static Service newInstance() {        return newInstance(DEFAULT_PROVIDER_NAME);    }    // 服務(wù)訪問API 

    public static Service newInstance(String name) {                Provider p = providers.get(name);        if(p == null) {            throw new IllegalArgumentException("No provider registered with name: " + name);        }        return p.newService();    }}

EntityProvider.java

public class EntityProvider implements Provider {    static {        ServiceManager.registerProvider("EntityService", new EntityProvider());    }        @Override    public Service newService() {        return new ServiceImpl();    }        class ServiceImpl implements Service {        @Override        public void serve() {            System.out.println("開始服務(wù)...");        }    }}

Test.java

public class Test {    public static void main(String[] args) throws ClassNotFoundException {                Class.forName("EntityProvider");                 Service s = ServiceManager.newInstance("EntityService");        s.serve();   

    }}

另推薦幾個(gè)對(duì)服務(wù)提供者框架解釋地不錯(cuò)的博文：

[1]. CSDN. 服務(wù)提供者框架（Service Provider Framework）

[2]. ITEYE. JAVA 服務(wù)提供者框架介紹