参考文档

http://www.cnblogs.com/panjun-Donet/archive/2008/09/27/1300609.html

泛型的主要目标是提高 Java 程序的类型安全。通过知道使用泛型定义的变量的类型限制，编译器可以在一个高得多的程度上验证类型假设。

 

可以查看下 Map, List , Future  等这些java 底层基础代码的写法，一目了然

下面举个我应用中碰到的例子以及写法，之所以举这个例子，主要是因为它包含了多种情况，1 参数是范型，2 返回值是范型，3，参数和返回值都是范型

app 产品中最不能缺的就是 push, 但是 ios 的推送 和 android 的推送还不一样，而且 android 推送还因为不同的第三方平台又不一样，比如小米推送，友盟推送，极光推送，百度云推送，个推推送等等

所以总思路是写一个通用接口，以及一个抽象类（主要是实现发送push）,因为发送push的流程都是一样的，见下面的代码

接口

package com.zyguo.tools.push;public interface IPush{    /**     * 异步发送PUSH     */    public boolean sendPushByAsyn( PushBody pushBody );        /**     * 同步发送PUSH     * @return 返回错误提示文案，若为 success， 说明发送成功     */    public String sendPushBySync( PushBody pushBody, int maxWaitSec );}

 

抽象类，因为不同的push通道，发送的消息格式是不一样的，而且返回值的格式也是不一样的（有json, xml ,byte 等等），所以定义了2个范型 M 代表消息，R代表返回值，private String sendPush(PushBody pushBody) {} 就是发送push的通用流程

package com.zyguo.tools.push;import java.util.concurrent.Callable;import java.util.concurrent.ExecutionException;import java.util.concurrent.Future;import java.util.concurrent.TimeUnit;import java.util.concurrent.TimeoutException;import org.apache.log4j.Logger;import com.zyguo.sdk.thread.BLThreadPool;import com.zyguo.sdk.utils.BUtils;public abstract class AbstractPush
     
       implements IPush {    protected Logger log = Logger.getLogger( this.getClass().getName() );    public final static String SUCCESS = "success";    private BLThreadPool threadPool = new BLThreadPool();        private String sendPush(PushBody pushBody) {        try {            if ( pushBody != null && BUtils.isNotBlank( pushBody.getToken() ) ) {                long begin = System.currentTimeMillis();                log.debug("begin send push:" + pushBody );                M msg = pushBody2message( pushBody );                R response = sendPush( msg, pushBody.getToken() );                 long end = System.currentTimeMillis();                log.debug("end push，result==" + response + ",耗时：" + ( end - begin ) + "毫秒");                if ( response != null ) {                    String result = dealPushResponse( response, pushBody );                    log.debug("send xiaomi push suceess," + pushBody );                    return result;                } else {                    log.error("no_response," + pushBody);                    return "no_response";                }            } else {                return "token is null";            }        } catch (Exception e) {            log.error("send xiaomi push exception", e);            return "exception:" + e.getMessage();        }            }        protected abstract String dealPushResponse( R response, PushBody pushBody );    protected abstract M pushBody2message( PushBody pushBody );    protected abstract R sendPush( M msg, String token );    @Override    public boolean sendPushByAsyn( final PushBody pushBody) {        threadPool.submit( new Runnable() {            public void run() {                sendPush( pushBody );            }        });        return true;    }        @Override    public String sendPushBySync( final PushBody pushBody, int maxWaitSec ) {        Future
      
        future = threadPool.submit( new Callable
       
        () {            public String call() throws Exception {                return sendPush( pushBody );            }        });                try {            String result = future.get( maxWaitSec, TimeUnit.SECONDS );            return result;        } catch (InterruptedException e) {            e.printStackTrace();        } catch (ExecutionException e) {            e.printStackTrace();        } catch (TimeoutException e) {            e.printStackTrace();        }         return null;    }    public void setThreadPool(BLThreadPool threadPool) {        this.threadPool = threadPool;    }}
       
      
     

 

小米 push 如下, 具体实现就不写出了

package com.zyguo.tools.push;import java.io.IOException;import org.json.simple.parser.ParseException;import com.xiaomi.push.sdk.ErrorCode;import com.xiaomi.xmpush.server.Constants;import com.xiaomi.xmpush.server.Message;import com.xiaomi.xmpush.server.Message.Builder;import com.xiaomi.xmpush.server.Result;import com.xiaomi.xmpush.server.Sender;public class XiaoMiPush extends AbstractPush
     
      {    private String appKey;    private String packageName;     @Override    protected Message pushBody2message( PushBody pushBody ){return null;    }        @Override    protected String dealPushResponse( Result response, PushBody pushBody ) {return SUCCESS;    }    @Override    protected Result sendPush(Message msg, String token) {return null;    } public void setAppKey(String appKey) {        this.appKey = appKey;    }    public void setPackageName(String packageName) {        this.packageName = packageName;    }}
     

iOS push 如下

package com.zyguo.tools.push;import com.xiaomi.push.sdk.ErrorCode;import com.xiaomi.xmpush.server.Constants;import com.xiaomi.xmpush.server.Message;import com.xiaomi.xmpush.server.Result;import com.xiaomi.xmpush.server.Sender;import com.zyguo.sdk.utils.BUtils;public class IOSPush extends AbstractPush
     
      {
        @Override    protected String dealPushResponse(Object response, PushBody pushBody) {        return null;    }    @Override    protected Payload pushBody2message(PushBody pushBody) {        return null;    }    @Override    protected boolean sendPush(Payload msg, String token) {        return null;    }}