Spring cloud实战从零开始一个简单搜索网站_Hystrix断路由的实现(三)-白红宇

Spring cloud实战从零开始一个简单搜索网站_Hystrix断路由的实现(三)

阅读量：4499 次

发布时间：2019-06-08

本文共 12898 字，大约阅读时间需要 42 分钟。

上文已经完成了一个简单的浏览器到 Client 到CSDN端的通路

我们的架构是每个博客网址为一个单独的组件，这里为了方便直接先用CSDN 那个组件复制下

我这里改成 SDN 修改下 application.properties 端口记得改

eureka.client.serviceUrl.defaultZone=http://localhost:8761/eureka/

spring.application.name=sdn

server.port=8983

下面是TOMCAT 和 eureka server运行的截图

好了有两个搜索端了，我这里把CSDN SDN 叫做搜索端了，下面修改下 Client端让他能分别调用2个组件

我修改了下github上的配置把我们新建的serviceID加入进去

我们会回到Client项目的 ClientService 多了个SDN，需要修改下代码，能让程序自动加载多个HOST（这里只是简单介绍，如果搜索端好几个肯定得改进）

@Servicepublic class ClientService {    @Autowired RestTemplate restTemplate;    @Autowired    private EurekaClient discoveryClient;        @Value("${serviceIds}")    public String serviceIds;        public String  search(String key,String page) {        StringBuffer sb =new StringBuffer();        if(serviceIds.contains(",")) {            String[] ids = serviceIds.split(",");            for(int i=0;i
     
       map = new HashMap<>();        map.put("key", key);        map.put("page", page);        String str= restTemplate.getForObject(serviceUrl(serviceId)+"/search?key={key}&page={page}",String.class,map);        return str;    }    @Bean    RestTemplate restTemplate() {        return new RestTemplate();    }    public String serviceUrl(String serviceId) {        InstanceInfo instance = discoveryClient.getNextServerFromEureka(serviceId, false);        return instance.getHomePageUrl();    }}

因为数据比较多我把两个搜索端直接改成返回一个字符串了

@RestControllerpublic class CsdnController {    Gson gson = new Gson();    @RequestMapping(value = "/search")    public String search(@RequestParam("key") String key, @RequestParam("page") String page) {        System.out.println("search");        ArrayList
      
       
        > result;        try {//            result = SearchUtil.search(key, "blog", page);//            return gson.toJson(result);            return "i am csdn 1";        } catch (Exception e) {            // TODO Auto-generated catch block            e.printStackTrace();        }        return null;    }}

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public class CsdnController {    Gson gson = new Gson();    @RequestMapping(value = "/search")    public String search(@RequestParam("key") String key, @RequestParam("page") String page) {        System.out.println("search");        ArrayList
      
       
        > result;        try {//            result = SearchUtil.search(key, "blog", page);//            return gson.toJson(result);            return "i am sdn 1";        } catch (Exception e) {            // TODO Auto-generated catch block            e.printStackTrace();        }        return null;    }}

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这下有两个端了，搜索时间也延长了2倍，但万一个端有异常另外一个端良好怎么办这时候就需要断路由 hystrix

在client pom里面导入下


             
      
       org.springframework.cloud
              
      
       spring-cloud-starter-netflix-hystrix

POM 代码


      
          
       
        4.0.0
           
       
        tsearch_web
           
       
        springtest-client
           
       
        0.0.1
           
       
        jar
           
       
        springtest-client
           
       
        Note Server catch
           
               
        
         org.springframework.boot
                
        
         spring-boot-starter-parent
                
        
         2.1.1.RELEASE
                
         
            
           
               
        
         UTF-8
                
        
         UTF-8
                
        
         1.8
                
        
         Greenwich.M3
            
           
               
                    
         
          org.springframework.boot
                     
         
          spring-boot-starter-freemarker
                 
                
                    
         
          org.springframework.boot
                     
         
          spring-boot-starter-web
                 
                
                    
         
          org.springframework.cloud
                     
         
          spring-cloud-starter-netflix-eureka-server
                 
                
                    
         
          org.springframework.cloud
                     
         
          spring-cloud-starter-config
                 
                
                    
         
          org.springframework.boot
                     
         
          spring-boot-starter-test
                     
         
          test
                 
                            
                
         
          org.springframework.cloud
                 
         
          spring-cloud-starter-netflix-hystrix
             
            
           
               
                    
                         
          
           org.springframework.cloud
                          
          
           spring-cloud-dependencies
                          
          
           Finchley.RELEASE
                          
          
           pom
                          
          
           import
                      
                 
            
           
               
                    
                         
          
           org.springframework.boot
                          
          
           spring-boot-maven-plugin
                      
                 
            
           
               
                    
         
          spring-milestones
                     
         
          Spring Milestones
                     
         
          https://repo.spring.io/milestone
                     
                         
          
           false

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修改下application

@EnableEurekaClient@SpringBootApplication@EnableCircuitBreakerpublic class SpringtestClientApplication {    public static void main(String[] args) {        SpringApplication.run(SpringtestClientApplication.class, args);    }}

新增个SearchUtil 类

@Componentpublic class SearchUtil  {     @Autowired    RestTemplate restTemplate;    @Autowired    private EurekaClient discoveryClient;        @HystrixCommand(groupKey = "searchDetail1", commandKey = "searchDetail1",fallbackMethod = "stubMyService")    public String searchDetail1(String key, String page, String serviceId) {        System.out.println("come="+serviceId);        HashMap
      
        map = new HashMap<>();        map.put("key", key);        map.put("page", page);        String str = restTemplate.getForObject(serviceUrl(serviceId) + "/search?key={key}&page={page}", String.class,                map);        return str;    }        @HystrixCommand(groupKey = "searchDetail2", commandKey = "searchDetail2",fallbackMethod = "stubMyService")    public String searchDetail2(String key, String page, String serviceId) {        System.out.println("come="+serviceId);        HashMap
       
         map = new HashMap<>();        map.put("key", key);        map.put("page", page);        String str = restTemplate.getForObject(serviceUrl(serviceId) + "/search?key={key}&page={page}", String.class,                map);        return str;    }        public String stubMyService(String key, String page, String serviceId) {        return "error";    }    @Bean    RestTemplate restTemplate() {        return new RestTemplate();    }    public String serviceUrl(String serviceId) {        InstanceInfo instance = discoveryClient.getNextServerFromEureka(serviceId, false);        return instance.getHomePageUrl();    }}

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修改下 ClientService

@Servicepublic class ClientService {    @Autowired    SearchUtil sc;    @Value("${serviceIds}")    public String serviceIds;    public String search(String key, String page) {        StringBuffer sb = new StringBuffer();        if (serviceIds.contains(",")) {            String[] ids = serviceIds.split(",");            sb.append(sc.searchDetail1(key, page, ids[0]));            sb.append(sc.searchDetail2(key, page, ids[1]));        }        else {            sb.append(sc.searchDetail1(key, page, serviceIds));        }        return sb.toString();    }}

不断刷新浏览器好像没啥区别

给CSDN的Client加个超载

@RestControllerpublic class CsdnController {    Gson gson = new Gson();    @RequestMapping(value = "/search")    public String search(@RequestParam("key") String key, @RequestParam("page") String page) {        System.out.println("search");        ArrayList
      
       
        > result;        try {//            result = SearchUtil.search(key, "blog", page);//            return gson.toJson(result);            Thread.sleep(5000);            return "i am csdn 1";        } catch (Exception e) {            // TODO Auto-generated catch block            e.printStackTrace();        }        return null;    }}

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继续刷新

然后看下控制台不是说好的垄断吗为啥还是进来了虽然时间减少了

用Hystrix的时候要注意一点 Hystrix的超时时间一点要大于resttemplete 或者你用 ribbon

Hystrix 的默认值全在 com.netflix.hystrix.HystrixCommandProperties

这个就是出错次数 private static final Integer default_circuitBreakerRequestVolumeThreshold = 20;// default => statisticalWindowVolumeThreshold: 20 requests in 10 seconds must occur before statistics matter

我们改下 SearchUtil

@Componentpublic class SearchUtil  {     @Autowired    RestTemplate restTemplate;    @Autowired    private EurekaClient discoveryClient;        @HystrixCommand(groupKey = "searchDetail1", commandKey = "searchDetail1",fallbackMethod = "stubMyService",            commandProperties = {                     @HystrixProperty(name = "circuitBreaker.requestVolumeThreshold",value = "5")                })    public String searchDetail1(String key, String page, String serviceId) {        System.out.println("come="+serviceId);        HashMap
      
        map = new HashMap<>();        map.put("key", key);        map.put("page", page);        String str = restTemplate.getForObject(serviceUrl(serviceId) + "/search?key={key}&page={page}", String.class,                map);        return str;    }        @HystrixCommand(groupKey = "searchDetail2", commandKey = "searchDetail2",fallbackMethod = "stubMyService")    public String searchDetail2(String key, String page, String serviceId) {        System.out.println("come="+serviceId);        HashMap
       
         map = new HashMap<>();        map.put("key", key);        map.put("page", page);        String str = restTemplate.getForObject(serviceUrl(serviceId) + "/search?key={key}&page={page}", String.class,                map);        return str;    }        public String stubMyService(String key, String page, String serviceId) {        return "error";    }    @Bean    RestTemplate restTemplate() {        return new RestTemplate();    }    public String serviceUrl(String serviceId) {        InstanceInfo instance = discoveryClient.getNextServerFromEureka(serviceId, false);        return instance.getHomePageUrl();    }}

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重启下不断刷新浏览器发现 searchDetail1方法不执行了好了垄断完成

我们需要知道组件的当前状态这时候就需要hystrix的dashbox

POM 中引入


              
       
        org.springframework.cloud
               
       
        spring-cloud-starter-netflix-hystrix-dashboard

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修改下ClientApplication 加入dashboard注释

@EnableEurekaClient@SpringBootApplication@EnableCircuitBreaker@EnableHystrixDashboardpublic class SpringtestClientApplication {    public static void main(String[] args) {        SpringApplication.run(SpringtestClientApplication.class, args);    }    @Bean    public ServletRegistrationBean getServlet() {        HystrixMetricsStreamServlet streamServlet = new HystrixMetricsStreamServlet();        ServletRegistrationBean registrationBean = new ServletRegistrationBean(streamServlet);        registrationBean.setLoadOnStartup(1);        registrationBean.addUrlMappings("/hystrix.stream");        registrationBean.setName("HystrixMetricsStreamServlet");        return registrationBean;    }}

在浏览器输入http://localhost:8881/hystrix 就能看到界面

按上面的填写好点击Monitor Stream就能进入统计页面

写个函数拼命跑会发现数字多有变化鼠标放上去可以看到具体说明

public class TestHystic {    public static void main(String[]  args) {        long time1=System.currentTimeMillis();        String b ="";        System.out.println(b.length());        for(int i=0;i<100;i++) {            try {                getData();                System.out.println("usertime="+(System.currentTimeMillis()-time1));                time1=System.currentTimeMillis();            } catch (Exception e) {                // TODO Auto-generated catch block                e.printStackTrace();            }        }    }        public static  void  getData() throws Exception {        URL serverUrl = new URL("http://localhost:8881/search?key=spring&page=1");        HttpURLConnection conn = (HttpURLConnection) serverUrl.openConnection();        InputStream in = conn.getInputStream();        BufferedReader br =new BufferedReader(new InputStreamReader(in, "UTF-8"));       StringBuffer sb= new StringBuffer();       String line;        while((line=br.readLine())!=null) {            sb.append(line);        }        System.out.println(sb.toString());        in.close();    }}

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