spring cloud开发Greenwich版：服务调用feign（七）

2019-09-12 11:35:14 | java

在实际应用中，spring cloud通常feign组件与服务提供者进行通信，feign有着更友好的api调用方式
我们改造微服务’ralab-client’

Add the Maven spring-cloud-config-server denpendency
Add @EnableFeignClients to the application class
Add FeignClient Interface communicate to microservice ‘ralab-nlp’

Add invoke Interface to RestController NlpResource

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.8.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.ralab</groupId>
    <artifactId>ralab-client</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>ralab-client</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
        <spring-cloud.version>Greenwich.SR3</spring-cloud.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>
        
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-hystrix</artifactId>
        </dependency>       

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        <!--添加依赖，获取配置服务器的相关配置信息-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-config</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

RalabClientApplication文件

package com.ralab.ralabclient;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.circuitbreaker.EnableCircuitBreaker;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.cloud.context.config.annotation.RefreshScope;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.cloud.openfeign.EnableFeignClients;
import org.springframework.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;

@SpringBootApplication
@EnableEurekaClient
@EnableCircuitBreaker
@EnableFeignClients
public class RalabClientApplication {

    @Bean
    @LoadBalanced
    public RestTemplate getRestTemplate()
    {
        return new RestTemplate();
    }

    public static void main(String[] args) {
        SpringApplication.run(RalabClientApplication.class, args);
    }

}

EurekaFeignService文件

package com.ralab.ralabclient.services;

import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.stereotype.Component;
import org.springframework.web.bind.annotation.RequestMapping;

@FeignClient(value = "nlp-service")
public interface EurekaFeignService {

    @RequestMapping(value = "nlp/api")
    String nlpService();
}

然后在NlpResource调用上面的feign接口

package com.ralab.ralabclient.resources;

import com.netflix.hystrix.contrib.javanica.annotation.HystrixCommand;
import com.ralab.ralabclient.services.EurekaFeignService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.cloud.context.config.annotation.RefreshScope;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

@RestController
@RequestMapping("/nlp")
@RefreshScope
public class NlpResource {

    @Autowired
    private RestTemplate restTemplate;
    
    @Autowired
    private EurekaFeignService eurekaFeignService;

    @Value("${example.property}")
    private String exampleProperty;

    @RequestMapping("/config")
    public String home() {
        return "exampleProperty:" + exampleProperty;
    }

    @GetMapping("/service")
    @HystrixCommand(fallbackMethod = "getFallbackIndex")
    public String index()
    {
      //String result = restTemplate.getForObject("http://localhost:8090/nlp/api", String.class);
      String result = restTemplate.getForObject("http://nlp-service/nlp/api", String.class);
      return result;
    }

    @GetMapping("/feign")
    @HystrixCommand(fallbackMethod = "getFallbackIndex")
    public String feignservice()
    {        
        String result = eurekaFeignService.nlpService();
        return result;
    }

    private String getFallbackIndex()
    {
        //String result = restTemplate.getForObject("http://localhost:8090/nlp/api", String.class);

        return "不好意思，没有获取到服务端信息";
    }
}

运行RalabClientApplication，打开http://localhost:8091/nlp/feign

spring cloud开发Greenwich版：断路器（六）

2019-09-12 10:12:09 | java

前面的文章主要探索的是微服务通信及服务发现（Communication and Discovery），接下来要解决的是容错及故障恢复（Fault Tolerance and Resilience）
当某个微服务出现故障时，确保系统能够正常运行及从故障中恢复
spring cloud采用了一种称之为断路器（Circuit breaker）的模式，本文主要演示该模式的Hystrix实现

这里是基于微服务’ralab-client’

Add the Maven spring-cloud-starter-netflix-hystrix denpendency
Add @EnableCircuitBreaker to the application class
Add @HystrixCommand to methods that need circuit breakers

configure Hystrix behavior
其pom.xml文件如下：

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.8.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.ralab</groupId>
    <artifactId>ralab-client</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>ralab-client</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
        <spring-cloud.version>Greenwich.SR2</spring-cloud.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-hystrix</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

RalabClientApplication文件

package com.ralab.ralabclient;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.circuitbreaker.EnableCircuitBreaker;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;

@SpringBootApplication
@EnableEurekaClient
@EnableCircuitBreaker
public class RalabClientApplication {

    @Bean
    @LoadBalanced
    public RestTemplate getRestTemplate()
    {
        return new RestTemplate();
    }

    public static void main(String[] args) {
        SpringApplication.run(RalabClientApplication.class, args);
    }

}

NlpResource文件

package com.ralab.ralabclient.resources;

import com.netflix.hystrix.contrib.javanica.annotation.HystrixCommand;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

@RestController
@RequestMapping("/nlp")
public class NlpResource {

    @Autowired
    private RestTemplate restTemplate;

    @GetMapping("/service")
    @HystrixCommand(fallbackMethod = "getFallbackIndex")
    public String index()
    {
      //String result = restTemplate.getForObject("http://localhost:8090/nlp/api", String.class);
      String result = restTemplate.getForObject("http://nlp-service/nlp/api", String.class);
      return result;
    }

    private String getFallbackIndex()
    {
        //String result = restTemplate.getForObject("http://localhost:8090/nlp/api", String.class);

        return "不好意思，没有获取到服务端信息";
    }
}

先停止微服务’ralab-nlp’，重新运行RalabClientApplication，测试http://localhost:8091/nlp/service

上面利用Hystrix实现了微服务’ralab-client’的容错及故障恢复功能，在其需要容错的方法上，还可以自定义相关参数，这里不再演示

spring cloud开发Greenwich版：服务调用RestTemplate（五）

2019-09-09 15:21:16 | java

建立注册服务器（ralab-server）并服务提供者（ralab-nlp）向其注册后，这时服务消费者（ralab-client，服务消费者也向注册服务器注册）可以通过访问注册服务器，查找服务实例名的方式查找服务提供者的相关信息，然后调用其服务

这里基于微服务’ralab-client’

Add @LoadBalanced to the RestTemplate Instance
Edit RestTemplate url parameter host as ‘nlp-service’

服务消费者ralab-client
RalabClientApplication文件

package com.ralab.ralabclient;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;

@SpringBootApplication
@EnableEurekaClient
public class RalabClientApplication {

    @Bean
    @LoadBalanced
    public RestTemplate getRestTemplate()
    {
        return new RestTemplate();
    }

    public static void main(String[] args) {
        SpringApplication.run(RalabClientApplication.class, args);
    }

}

修改NlpResource文件

package com.ralab.ralabclient.resources;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

@RestController
@RequestMapping("/nlp")
public class NlpResource {

    @Autowired
    private RestTemplate restTemplate;

    @GetMapping("/service")
    public String index()
    {
      //String result = restTemplate.getForObject("http://localhost:8090/nlp/api", String.class);
      String result = restTemplate.getForObject("http://nlp-service/nlp/api", String.class);
      return result;
    }
}

运行RalabClientApplication

测试http://localhost:8091/nlp/service

spring cloud开发Greenwich版：注册服务器（四）

2019-09-09 15:01:07 | java

这里基于微服务’ralab-nlp’和’ralab-client’

Add the Maven spring-cloud-starter-netflix-eureka-client denpendency
Add @EnableEurekaClient to the application class
Add spring.application.name parameter to the application.properties file

这时修改服务提供者ralab-nlp的pom.xml文件，引入eureka-client依赖

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.8.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.ralab</groupId>
    <artifactId>ralab-nlp</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>ralab-nlp</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
        <spring-cloud.version>Greenwich.SR2</spring-cloud.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

修改RalabNlpApplication文件

package com.ralab.ralabnlp;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.context.annotation.ComponentScan;

//(scanBasePackages = { "com.ralab.nlp.controller"})
//@ComponentScan({"com.ralab.nlp.controller"})
@SpringBootApplication
@EnableEurekaClient
public class RalabNlpApplication {

    public static void main(String[] args) {
        SpringApplication.run(RalabNlpApplication.class, args);
    }

}

修改application.properties文件
spring.application.name=nlp-service
server.port=8090

运行RalabNlpApplication

同时修改服务消费者ralab-client的pom.xml文件，引入eureka-client依赖

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.8.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.ralab</groupId>
    <artifactId>ralab-client</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>ralab-client</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
        <spring-cloud.version>Greenwich.SR2</spring-cloud.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

修改RalabClientApplication文件

package com.ralab.ralabclient;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;

@SpringBootApplication
@EnableEurekaClient
public class RalabClientApplication {

    @Bean
    public RestTemplate getRestTemplate()
    {
        return new RestTemplate();
    }

    public static void main(String[] args) {
        SpringApplication.run(RalabClientApplication.class, args);
    }

}

修改application.properties文件
spring.application.name=nlp-client
server.port=8091

运行RalabClientApplication

这时在浏览器打开http://localhost:8761/

可以看到注册实例nlp-service和nlp-client

spring cloud开发Greenwich版：注册服务器（三）

2019-09-09 14:25:48 | java

前两文中的建立的项目，在逻辑上可分为服务提供者（ralab-nlp）和服务消费者（ralab-client），服务消费者采用RestTemplate与之通信
在spring cloude中，采用了服务注册的方式，所有的服务提供者及服务消费者都向注册服务器注册，然后服务消费者从注册服务器上查询相关服务

微服务’ralab-server’

New microservice ‘ralab-server’ and add the Maven spring-cloud-starter-netflix-eureka-server denpendency
Add @EnableEurekaServer to the application class

本文建立注册服务器（注册服务器ralab-server），引入eureka-server依赖，pom.xml文件如下：

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.8.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.ralab</groupId>
    <artifactId>ralab-server</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>ralab-server</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
        <spring-cloud.version>Greenwich.SR2</spring-cloud.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

RalabServerApplication文件

package com.ralab.ralabserver;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;

@SpringBootApplication
@EnableEurekaServer
public class RalabServerApplication {

    public static void main(String[] args) {
        SpringApplication.run(RalabServerApplication.class, args);
    }

}

运行RalabServerApplication

打开浏览器http://localhost:8761/

这时没有发现注册实例

spring cloud开发Greenwich版：服务消费者及服务调用（二）

2019-09-09 13:41:38 | java

上文采用spring boot建立了restful项目，本文建立新的项目，并处理与之通信
先设置上文应用程序的端口，resources文件夹application.properties
server.port=8090

微服务’ralab-client’

New mocroservice ‘ralab-client’ and add the Maven spring-boot-starter-web denpendency
Add server.port parameter to the application.properties file
Add RestTemplate instance to Communicate with mocroservice ‘ralab-nlp’ by url

新建maven项目（服务消费者ralab-client），引入spring-web依赖，pom.xml文件如下：

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.8.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.ralab</groupId>
    <artifactId>ralab-client</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>ralab-client</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

RalabClientApplication文件

package com.ralab.ralabclient;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;

@SpringBootApplication
public class RalabClientApplication {

    @Bean
    public RestTemplate getRestTemplate()
    {
        return new RestTemplate();
    }

    public static void main(String[] args) {
        SpringApplication.run(RalabClientApplication.class, args);
    }

}

新建NlpResource

package com.ralab.ralabclient.resources;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

@RestController
@RequestMapping("/nlp")
public class NlpResource {

    @Autowired
    private RestTemplate restTemplate;

    @GetMapping("/service")
    public String index()
    {
      String result = restTemplate.getForObject("http://localhost:8090/nlp/api", String.class);
      return result;
    }
}

设置端口
resources文件夹application.properties
server.port=8091

运行RalabClientApplication

测试http://localhost:8091/nlp/service

spring cloud开发Greenwich版：服务提供者（一）

2019-09-08 13:30:06 | java

微服务’ralab-nlp’

New mocroservice ‘ralab-nlp’ and add the Maven spring-boot-starter-web denpendency
Add @SpringBootApplication to the application class
Add HelloController

本文采用maven建立应用程序（服务提供者ralab-nlp），引入spring-web依赖，pom.xml配置如下

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.8.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.ralab</groupId>
    <artifactId>ralab-nlp</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>ralab-nlp</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

自动生成RalabNlpApplication.java代码

package com.ralab.ralabnlp;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.ComponentScan;

//(scanBasePackages = { "com.ralab.nlp.controller"})
@SpringBootApplication
@ComponentScan({"com.ralab.nlp.controller"})
public class RalabNlpApplication {

    public static void main(String[] args) {
        SpringApplication.run(RalabNlpApplication.class, args);
    }

}

新建HelloController.java

package com.ralab.nlp.controller;


//import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("/nlp")
public class HelloController {

    @GetMapping("/api")
    public String index() {
        return "Greetings from Spring Boot!";
    }
}

运行RalabNlpApplication

测试http://localhost:8080/nlp/api

python数据分析（一）

2019-08-20 04:24:25 | python数据分析

import pandas as pd
import matplotlib.pyplot as plt

df = pd.read_csv('datasets/avocado.csv')

df.head()

df.tail()

1	df['AveragePrice'].head()

0    1.33
1    1.35
2    0.93
3    1.08
4    1.28
Name: AveragePrice, dtype: float64

1	df.AveragePrice.head()

0    1.33
1    1.35
2    0.93
3    1.08
4    1.28
Name: AveragePrice, dtype: float64

1 2	albany_df = df[df['region'] == 'Albany'] albany_df.head()

1	albany_df.index

Int64Index([    0,     1,     2,     3,     4,     5,     6,     7,     8,
                9,
            ...
            17603, 17604, 17605, 17606, 17607, 17608, 17609, 17610, 17611,
            17612],
           dtype='int64', length=338)

1 2	albany_df = albany_df.set_index('Date') albany_df.head()

1	albany_df.index

Index(['2015-12-27', '2015-12-20', '2015-12-13', '2015-12-06', '2015-11-29',
       '2015-11-22', '2015-11-15', '2015-11-08', '2015-11-01', '2015-10-25',
       ...
       '2018-03-11', '2018-03-04', '2018-02-25', '2018-02-18', '2018-02-11',
       '2018-02-04', '2018-01-28', '2018-01-21', '2018-01-14', '2018-01-07'],
      dtype='object', name='Date', length=338)

1	albany_df.plot()

<matplotlib.axes._subplots.AxesSubplot at 0x15c18c71e88>

1	albany_df['AveragePrice'].plot()

<matplotlib.axes._subplots.AxesSubplot at 0x15c18ad00c8>

python开发：opencv图像处理（三）

2019-08-14 21:02:00 | pythonopencv

本文加载摄像头，显示视频，并写入文件

import numpy as np
import cv2

cap = cv2.VideoCapture(0)
fourcc = cv2.VideoWriter_fourcc(*'XVID')
out = cv2.VideoWriter('output.avi',fourcc, 20.0, (640,480))

while(True):
    ret, frame = cap.read()
    gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
    out.write(frame)
    cv2.imshow('frame',gray)
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break

cap.release()
out.release()
cv2.destroyAllWindows()

python开发：opencv图像处理（二）

2019-08-14 20:55:57 | pythonopencv

上文已经安装了opencv的开发环境

这里测试图像显示及写入

# 导入cv模块
import cv2 as cv
# 读取图像，支持 bmp、jpg、png、tiff 等常用格式
img = cv.imread("data/lena.jpg", cv.IMREAD_COLOR)
# 创建窗口并显示图像
cv.imshow("Image", img)
cv.waitKey(0)
# 释放窗口
cv.destroyAllWindows()

cv.imwrite('lena2.jpg', img)

chenying99'blog

君子博学而日参省乎己，则知明而行无过矣

spring cloud开发Greenwich版：服务调用feign（七）

spring cloud开发Greenwich版：断路器（六）

spring cloud开发Greenwich版：服务调用RestTemplate（五）

spring cloud开发Greenwich版：注册服务器（四）

spring cloud开发Greenwich版：注册服务器（三）

spring cloud开发Greenwich版：服务消费者及服务调用（二）

spring cloud开发Greenwich版：服务提供者（一）

python数据分析（一）

python开发：opencv图像处理（三）

python开发：opencv图像处理（二）