以前一直使用的极光的手动输入推送内容然后推送到客户端，今天遇到了推送频率比较高且比较有规律的内容，比如事实天气。这样就需要用我们自己的服务器来自动生成推送内容了。

在官方的SDK文档中找了半天，终于找到了有点类似的接口了，进去先看看：

可以看到，上面两句话很醒目，我们看看它封装的REST API是个什么东西，再点进去看看

上面两句话读了一下，看来我们的运气还不错，这个应该就是了。

好了我们进入上面的Java开发部分：

进去看了半天，大概明白意思了，已经帮助我们封装好了，现在我们只需要下载jar包和它提供的实例文档。

进去后发现又对RESI API进行了更详细的说明，比如参数、频率限制等。

好吧，我们看看推送消息和通知，如下图点击进入

进去之后就看到了真真需要的api接口了，这里有各个方法和参数的说明。如果有的朋友还觉得看不懂，简单，直接下载示例代码（抄袭谁不会啊）

我下载官方示例代码，新建立了一个项目如下：

消息发送端代码：

package com.meritit.tuisong.service;import java.util.HashMap;import java.util.Map;import cn.jpush.api.ErrorCodeEnum;import cn.jpush.api.IOSExtra;import cn.jpush.api.JPushClient;import cn.jpush.api.MessageResult;public class JPushClientExample {	private static final String appKey ="5d30bebd28335593a13454861";	//必填，例如466f7032ac604e02fb7bda89	private static final String masterSecret = "0e0cc80c6f6a4703bec9ed191";//"13ac09b17715bd117163d8a1";//必填，每个应用都对应一个masterSecret	private static JPushClient jpush = null;	/**	 * 保存离线的时长。秒为单位。最多支持10天（864000秒）。	 * 0 表示该消息不保存离线。即：用户在线马上发出，当前不在线用户将不会收到此消息。	 * 此参数不设置则表示默认，默认为保存1天的离线消息（86400秒)。	 */	private static long timeToLive =  60 * 60 * 24;  	public static void main(String[] args) {		/*		 * Example1: 初始化,默认发送给android和ios，同时设置离线消息存活时间		 * jpush = new JPushClient(masterSecret, appKey, timeToLive);		 */		/*				 * Example2: 只发送给android		 * jpush = new JPushClient(masterSecret, appKey, DeviceEnum.Android);		 */		/*		 * Example3: 只发送给IOS		 * jpush = new JPushClient(masterSecret, appKey, DeviceEnum.IOS);		 */		/*		 * Example4: 只发送给android,同时设置离线消息存活时间		 * jpush = new JPushClient(masterSecret, appKey, timeToLive, DeviceEnum.Android);		 */		jpush = new JPushClient(masterSecret, appKey, timeToLive);		/*		 * 是否启用ssl安全连接, 可选		 * 参数：启用true， 禁用false，默认为非ssl连接		 */		//jpush.setEnableSSL(true);		//测试发送消息或者通知		testSend();	}	private static void testSend() {		// 在实际业务中，建议 sendNo 是一个你自己的业务可以处理的一个自增数字。		// 除非需要覆盖，请确保不要重复使用。详情请参考 API 文档相关说明。		int sendNo = getRandomSendNo();		String msgTitle = "+;//jpush\"\"";		String msgContent = "\\&;w\"\"a--【\npush】";		/*		 * IOS设备扩展参数,		 * 设置badge，设置声音		 */		Map
    
      extra = new HashMap
     
      ();		IOSExtra iosExtra = new IOSExtra(10, "WindowsLogonSound.wav");		extra.put("ios", iosExtra);		//对所有用户发送通知, 更多方法请参考文档		MessageResult msgResult = jpush.sendCustomMessageWithAppKey(sendNo,msgTitle, msgContent);		//MessageResult msgResult  = jpush.sendNotificationWithAlias(sendNo, "a", msgTitle, msgContent);		//覆盖指定msgId的消息,msgId可以从msgResult.getMsgid()获取。		//MessageResult msgResult = jpush.sendNotificationWithAppKey(sendNo, msgTitle, msgContent, 0, extra,msgResult.getMsgid());		if (null != msgResult) {			System.out.println("服务器返回数据: " + msgResult.toString());			if (msgResult.getErrcode() == ErrorCodeEnum.NOERROR.value()) {				System.out.println(String.format("发送成功， sendNo= %s,messageId= %s",msgResult.getSendno(),msgResult.getMsg_id()));			} else {				System.out.println("发送失败， 错误代码=" + msgResult.getErrcode() + ", 错误消息=" + msgResult.getErrmsg());			}		} else {			System.out.println("无法获取数据");		}	}	public static final int MAX = Integer.MAX_VALUE;	public static final int MIN = (int) MAX/2;	/**	 * 保持 sendNo 的唯一性是有必要的	 * It is very important to keep sendNo unique.	 * @return sendNo	 */	public static int getRandomSendNo() {		return (int) (MIN + Math.random() * (MAX - MIN));	}}
     
    

执行结果如下：

消息接收端代码：

package com.meritit.tuisong.service;import java.util.List;import cn.jpush.api.JPushClient;import cn.jpush.api.receive.ReceiveResult;public class ReceiveClientExample {	private static final String appKey ="5d30bebd28335593a13454861";	//必填，例如466f7032ac604e02fb7bda89	private static final String masterSecret = "0e0cc80c6f6a4703bec9ed191";//"13ac09b17715bd117163d8a1";//必填			public static void main(String[] args) {		JPushClient JPushClient = new JPushClient(masterSecret, appKey);				String msgId = "1236722141";				String[] msgIds = {"1236722141","910981248","911034889"};				//获取一条		ReceiveResult receiveResult =  JPushClient.getReceived(msgId);		if(receiveResult == null){			System.out.println("获取receive 数据失败！"+receiveResult);		}else{			//gson toJson 之后，NULL值的字段会被过滤掉			System.out.println("received result:"+receiveResult.toString());		}				// 获取多条		List
    
      receiveResults = JPushClient.getReceiveds(msgIds);		if(receiveResults == null ){			System.out.println("获取receive 数据失败！");		}else{			System.out.println("成功获取了："+receiveResults);		}		}}
    

执行结果：

测试已经成功，下面我们来看看源代码是怎么做的，其他的其实只是数据封装，我们来看看关键的一句代码

MessageResult msgResult = jpush.sendCustomMessageWithAppKey(sendNo,msgTitle, msgContent);

查看源代码，如下：

public MessageResult sendCustomMessageWithAppKey(int sendNo, String msgTitle, String msgContent) {		CustomMessageParams p = new CustomMessageParams();		p.setReceiverType(ReceiverTypeEnum.APPKEYS);		return sendCustomMessage(p, sendNo, msgTitle, msgContent, null, null);	}

发现实际是调用的sendCustomMessage方法

protected MessageResult sendCustomMessage(CustomMessageParams p, int sendNo, String msgTitle, String msgContent, String msgContentType, Map
    
      extra) {		if (null != msgContentType) {			p.getMsgContent().setContentType(msgContentType);		}		if (null != extra) {			p.getMsgContent().setExtra(extra);		}		return sendMessage(p, sendNo, msgTitle, msgContent);	}
    

这里进行了空值判断，实际又调用了sendMessage方法

protected MessageResult sendMessage(MessageParams p, int sendNo, String msgTitle, String msgContent) {		p.setSendNo(sendNo);		p.setAppKey(this.getAppKey());		p.setMasterSecret(this.masterSecret);		p.setTimeToLive(this.timeToLive);		p.setSendDescription(this.getSendDescription());		for (DeviceEnum device : this.getDevices()) {			p.addPlatform(device);		}		if (null != msgTitle) {			p.getMsgContent().setTitle(msgTitle);		}		p.getMsgContent().setMessage(msgContent);			return sendMessage(p);	}

在这里将参数封装到消息对象中调用sendMessage

protected MessageResult sendMessage(MessageParams params) {		return httpClient.sendPush(BaseURL.ALL_PATH, enableSSL, params);	}

再进到sendPush方法中看看，哦，大概明白了，实际上是用的http请求发送消息的。

public MessageResult sendPush(final String path, final boolean enableSSL, final MessageParams messageParams) {		MessageResult messageResult = ValidateRequestParams.vidateParams(messageParams);		if(messageResult != null) return messageResult;		String pushResult = sendPost(path, enableSSL, parse(messageParams),RequestTypeEnum.PUSH.value(),null);		return gson.fromJson(pushResult, MessageResult.class);	}

关键看倒数第二行代码

private String sendPost( String path, final boolean enableSSL, String params,Integer reqeustType,String authCode){		return sendRequest(path, enableSSL, params, "POST", reqeustType,authCode);	}

private String sendRequest(String path, final boolean enableSSL, String params,String method,Integer reqeustType,String authCode){		HttpURLConnection conn = null;		DataOutputStream outStream = null;		StringBuffer sb = new StringBuffer();		try {			if (enableSSL) {				initSSL();			}						URL url = new URL(BaseURL.getUrlForPath(path,enableSSL,reqeustType));			conn = (HttpURLConnection) url.openConnection();			conn.setConnectTimeout(DEFAULT_CONNECTION_TIMEOUT);			conn.setReadTimeout(DEFAULT_SOCKET_TIMEOUT);			conn.setUseCaches(false);			conn.setDoOutput(true);			conn.setRequestMethod(method);			conn.setRequestProperty("Connection", "Keep-Alive");			conn.setRequestProperty("Charset", CHARSET);			if(authCode != null && !authCode.isEmpty()){				conn.setRequestProperty("Authorization", authCode);			}			if(method.equals("POST")){				byte[] data = params.getBytes(CHARSET);				conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");				conn.setRequestProperty("Content-Length", String.valueOf(data.length));				outStream = new DataOutputStream(conn.getOutputStream());				outStream.write(data);				outStream.flush();			}			if (conn.getResponseCode() == 200) {				logger.info("Congratulations!The request was successful. response status is 200");				InputStream in = conn.getInputStream();				InputStreamReader reader = new InputStreamReader(in, CHARSET);				char[] buff = new char[1024];				int len;				while ((len = reader.read(buff)) > 0) {					sb.append(buff, 0, len);				}			} else {						logger.log(Level.WARNING,"Sorry!The request was fault. response " +						"status = "+conn.getResponseCode()+",errormsg = "+conn.getHeaderField(0));				String errmsg = "";				if(reqeustType == RequestTypeEnum.RECEIVE.value()){					errmsg = ErrorCodeEnum.errorMsg(conn.getResponseCode());					errmsg = errmsg == null ? conn.getHeaderField(0) : errmsg;				}else{					errmsg = conn.getHeaderField(0);				}				BaseResult result = new BaseResult(errmsg,conn.getResponseCode());				return result.toString();			}		}		catch (SocketTimeoutException e) {					logger.log(Level.SEVERE,"God! the server throw SocketTimeout Exception." +					"please check it out the error message:"+e.getMessage());			BaseResult baseResult = new BaseResult(e.getMessage().toString(),ErrorCodeEnum.CONNECTIONTIMEOUT.value());			return baseResult.toString();		}		catch (ConnectException e) {			logger.log(Level.SEVERE,"God! the server throw Connect Exception ." +					"please check it out the error message:"+e.getMessage());			BaseResult baseResult = new BaseResult(e.getMessage().toString(),ErrorCodeEnum.CONNECTIONREFUSED.value());			return baseResult.toString();		}		catch (UnknownHostException e) {			logger.log(Level.SEVERE,"God! the server throw UnknownHost Exception ." +					"please check it out the error message:"+e.getMessage());			BaseResult baseResult = new BaseResult(e.getMessage().toString(),ErrorCodeEnum.CONNECTIONREFUSED.value());			return baseResult.toString();		}		catch (Exception e) {			logger.log(Level.SEVERE,"God! the server throw exception." +					"please check it out the error message:"+e.getMessage());			BaseResult baseResult = new BaseResult(e.getMessage().toString(),ErrorCodeEnum.UnknownException.value());			return baseResult.toString();		} 		finally {					if (null != outStream) {				try {					outStream.close();				} catch (IOException e) {					e.printStackTrace();				}			}			if (null != conn) {				conn.disconnect();			}		}		return sb.toString();	}

学过Android的朋友对这个应该很熟悉吧！比如里面的URL请求地址,看第9行代码

URL url = new URL(BaseURL.getUrlForPath(path,enableSSL,reqeustType));

public  static String getUrlForPath(final String path,boolean enableSSL,Integer type) {		return getHostname(enableSSL,type) + path;	}

private static String getHostname(boolean enableSSL,Integer type) {		if(type == RequestTypeEnum.PUSH.value())			return enableSSL? HOST_NAME_SSL :HOST_NAME;				if(type == RequestTypeEnum.RECEIVE.value())			return enableSSL? RECEIVE_HOST_NAME:RECEIVE_HOST_NAME;				return null;	}

在这里进行判断，如果enableSSL为false则发送消息请求地址为HOST_NAME,实际上这个enableSSL在BaseClient类中默认为false

public boolean enableSSL = false;

HOST_NAME就是官方文档中所说的默认请求地址：

public static String HOST_NAME = "http://api.jpush.cn:8800";

public static  String RECEIVE_HOST_NAME = "https://report.jpush.cn:443";