HTTP和MQTT初识

一、HTTP

1、读取指定城市的天气预报信息

配置好Java环境和IDE,网上方法很多这里就不赘述了。
这里我使用的Java版本是JAVA11,IDE是IDEA。
代码如下:

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.URL;
import java.net.URLConnection;

public class weather {
 public static void main(String args[]) throws IOException
{
	URL url = new URL("https://api.jisuapi.com/iqa/query?appkey=62958a3a6ef3c56d&question=重庆天气");
	URLConnection conn = url.openConnection();
	InputStream is = conn.getInputStream();
	BufferedReader br = new BufferedReader(new InputStreamReader(is));
	String text = br.readLine();
	System.out.println(text);
	br.close();
}
}

之后编译运行即可
结果
在这里插入图片描述

2、给指定手机号码发送验证码

短信服务提供商提供的短信接口是收费的,国内可以选择阿里云的,也可以使用其他的。网上能找到免费的,但需要魔法。
这里是我的源码:

public class HttpClientUtil {  
    private RequestConfig requestConfig = RequestConfig.custom()  
            .setSocketTimeout(15000)  
            .setConnectTimeout(15000)  
            .setConnectionRequestTimeout(15000)  
            .build();  
      
    private static HttpClientUtil instance = null;  
    private HttpClientUtil(){}  
    public static HttpClientUtil getInstance(){  
        if (instance == null) {  
            instance = new HttpClientUtil();  
        }  
        return instance;  
    }  
      
    /** 
     * 发送 post请求 
     * @param httpUrl 地址 
     */  
    public String sendHttpPost(String httpUrl) {  
        HttpPost httpPost = new HttpPost(httpUrl);// 创建httpPost    
        return sendHttpPost(httpPost,"utf-8");  
    }  
      
      
    /** 
     * 发送 post请求 
     * @param httpUrl 地址 
     * @param maps 参数 
     *  @param type 字符编码格式 
     */  
    public String sendHttpPost(String httpUrl, Map<String, String> maps,String type) {  
        HttpPost httpPost = new HttpPost(httpUrl);// 创建httpPost    
        // 创建参数队列    
        List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>();  
        for (String key : maps.keySet()) {  
            nameValuePairs.add(new BasicNameValuePair(key, maps.get(key)));  
        }  
        try {  
            httpPost.setEntity(new UrlEncodedFormEntity(nameValuePairs, type));  
        } catch (Exception e) {  
            e.printStackTrace();  
        }  
        return sendHttpPost(httpPost,type);  
    }  
      
    /** 
     * 发送Post请求 
     * @param httpPost 
     * @return 
     */  
    private String sendHttpPost(HttpPost httpPost,String reponseType) {  
        CloseableHttpClient httpClient = null;  
        CloseableHttpResponse response = null;  
        HttpEntity entity = null;  
        String responseContent = null;  
        try {  
            // 创建默认的httpClient实例.  
            httpClient = HttpClients.createDefault();  
            httpPost.setConfig(requestConfig);  
            // 执行请求  
            response = httpClient.execute(httpPost);  
            entity = response.getEntity();  
            responseContent = EntityUtils.toString(entity, reponseType);  
        } catch (Exception e) {  
            e.printStackTrace();  
        } finally {  
            try {  
                // 关闭连接,释放资源  
                if (response != null) {  
                    response.close();  
                }  
                if (httpClient != null) {  
                    httpClient.close();  
                }  
            } catch (IOException e) {  
                e.printStackTrace();  
            }  
        }  
        return responseContent;  
    }  
  
    /** 
     * 发送 get请求 
     * @param httpUrl 
     */  
    public String sendHttpGet(String httpUrl) {  
        HttpGet httpGet = new HttpGet(httpUrl);// 创建get请求  
        return sendHttpGet(httpGet);  
    }  
      
    /** 
     * 发送 get请求Https 
     * @param httpUrl 
     */  
    public String sendHttpsGet(String httpUrl) {  
        HttpGet httpGet = new HttpGet(httpUrl);// 创建get请求  
        return sendHttpsGet(httpGet);  
    }  
    
    /**
     * @Title: sendMsgUtf8
     * @Description: TODO(发送utf8)
     * @param: @param Uid
     * @param: @param Key
     * @param: @param content
     * @param: @param mobiles
     * @param: @return      
     * @date: 2017-3-22 下午5:58:07
     * @throws
     */
    @SuppressWarnings({ "rawtypes", "unchecked" })
    public int sendMsgUtf8(String Uid,String Key,String content,String mobiles){
    	Map maps = new HashMap();
		maps.put("Uid", Uid);
		maps.put("Key", Key);
		maps.put("smsMob", mobiles);
		maps.put("smsText", content);
		String result = sendHttpPost("http://utf8.sms.webchinese.cn", maps, "utf-8");
		return Integer.parseInt(result);
    }
    
    /**
     * @Title: sendMsgUtf8
     * @Description: TODO(发送utf8)
     * @param: @param Uid
     * @param: @param Key
     * @param: @param content
     * @param: @param mobiles
     * @param: @return     
     * @return: int     
     * @author:  ly
     * @date: 2017-3-22 下午5:58:07
     * @throws
     */
    @SuppressWarnings({ "rawtypes", "unchecked" })
	public int sendMsgGbk(String Uid,String Key,String content,String mobiles){
    	Map maps = new HashMap();
		maps.put("Uid", Uid);
		maps.put("Key", Key);
		maps.put("smsMob", mobiles);
		maps.put("smsText", content);
		String result = sendHttpPost("http://gbk.sms.webchinese.cn", maps, "gbk");
		return Integer.parseInt(result);
    }
      
    /** 
     * 发送Get请求 
     * @param httpPost 
     * @return 
     */  
    private String sendHttpGet(HttpGet httpGet) {  
        CloseableHttpClient httpClient = null;  
        CloseableHttpResponse response = null;  
        HttpEntity entity = null;  
        String responseContent = null;  
        try {  
            // 创建默认的httpClient实例.  
            httpClient = HttpClients.createDefault();  
            httpGet.setConfig(requestConfig);  
            // 执行请求  
            response = httpClient.execute(httpGet);  
            entity = response.getEntity();  
            responseContent = EntityUtils.toString(entity, "UTF-8");  
        } catch (Exception e) {  
            e.printStackTrace();  
        } finally {  
            try {  
                // 关闭连接,释放资源  
                if (response != null) {  
                    response.close();  
                }  
                if (httpClient != null) {  
                    httpClient.close();  
                }  
            } catch (IOException e) {  
                e.printStackTrace();  
            }  
        }  
        return responseContent;  
    }  
      
    /** 
     * 发送Get请求Https 
     * @param httpPost 
     * @return 
     */  
    private String sendHttpsGet(HttpGet httpGet) {  
        CloseableHttpClient httpClient = null;  
        CloseableHttpResponse response = null;  
        HttpEntity entity = null;  
        String responseContent = null;  
        try {  
            // 创建默认的httpClient实例.  
            PublicSuffixMatcher publicSuffixMatcher = PublicSuffixMatcherLoader.load(new URL(httpGet.getURI().toString()));  
            DefaultHostnameVerifier hostnameVerifier = new DefaultHostnameVerifier(publicSuffixMatcher);  
            httpClient = HttpClients.custom().setSSLHostnameVerifier(hostnameVerifier).build();  
            httpGet.setConfig(requestConfig);  
            // 执行请求  
            response = httpClient.execute(httpGet);  
            entity = response.getEntity();  
            responseContent = EntityUtils.toString(entity, "UTF-8");  
        } catch (Exception e) {  
            e.printStackTrace();  
        } finally {  
            try {  
                // 关闭连接,释放资源  
                if (response != null) {  
                    response.close();  
                }  
                if (httpClient != null) {  
                    httpClient.close();  
                }  
            } catch (IOException e) {  
                e.printStackTrace();  
            }  
        }  
        return responseContent;  
    }  
    
    /**
	 * @Title: getErrorMsg
	 * @Description: TODO(返回异常原因)
	 * @param: @param errorCode
	 */
	public String getErrorMsg(int errorCode){
		if(errorCode==-1){
			return "没有该用户账户";
		}else if(errorCode==-2){
			return "接口密钥不正确";
		}else if(errorCode==-3){
			return "短信数量不足";
		}else if(errorCode==-4){
			return "手机号格式不正确";
		}else if(errorCode==-21){
			return "MD5接口密钥加密不正确";
		}else if(errorCode==-11){
			return "该用户被禁用";
		}else if(errorCode==-14){
			return "短信内容出现非法字符";
		}else if(errorCode==-41){
			return "手机号码为空";
		}else if(errorCode==-42){
			return "短信内容为空";
		}else if(errorCode==-51){
			return "短信签名格式不正确";
		}else if(errorCode==-6){
			return "IP限制";
		}else{
			return "未知错误码:"+errorCode;
		}
	}
} 
public class test {
	
	//用户名
	private static String Uid = "uid";
	
	//接口安全秘钥
	private static String Key = "key";
	
	//手机号码,多个号码如13800000000,13800000001,13800000002
	private static String smsMob = "13800000000";
	
	//短信内容
	private static String smsText = "验证码:8888";
	
	
	public static void main(String[] args) {
		
		HttpClientUtil client = HttpClientUtil.getInstance();
		
		//UTF发送
		int result = client.sendMsgUtf8(Uid, Key, smsText, smsMob);
		if(result>0){
			System.out.println("UTF8成功发送条数=="+result);
		}else{
			System.out.println(client.getErrorMsg(result));
		}
	}
}

之后编译运行即可。
在这里插入图片描述

二、MQTT

1、服务器搭建

下载和安装Apollo服务器
此处为下载链接
然后解压到一个目录,进入dos窗口(cmd命令行窗口)切换到Apollo的目录,进入bin目录,然后运行“apollo.cmd create mybroker”创建服务器实例。
在这里插入图片描述
在这里插入图片描述
创建实例后会在bin目录下生成用户目录,这里是mybroker,里面有配置服务器信息的文件,和包含连接mqtt服务器的用户名和密码。
启动MQTT。
在这里插入图片描述

2.客户端连接MQTT服务器

这里使用mqttbox
Client Name 随便填

Protocol 选择 mqtt / tcp
Host:MQTT服务器的IP地址和端口、Username 和 Password查看bin目录下的用户目录的配置信息查看填写
在这里插入图片描述
连接成功后,就可以发布-订阅消息了
在这里插入图片描述

小结

通过对MQTT的发布订阅模式的认识,可以很清楚的看到通信的整个过程。客户端的实现,主要包含三个部分,第一部分是实现连接MQTT服务器,第二部分是实现消息的订阅,第三部分是消息的发布。通过运行这个程序,你会发现即使订阅主题的客户端没有运行,发布客户端仍旧会按照规定进行发布消息。由此,可以看出发布者和订阅者两者之间并不会对对方造成影响。这便是这种方式通信的优点所在。

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