SpringBoot的学习与使用

短命女 2021-09-21 06:48 285阅读 0赞

# SpringBoot和SpringCloud的学习与使用 #

本文是基于SpringBoot 2.0.4.release环境，学习和使用SpringBoot：

*  **SpringBoot 2.0.4.release**

--------------------

## 一、SpringBoot介绍 ##

### （1）什么是SpringBoot ###

Spring Boot是一个用来搭建Spring应用的脚手架，为了简化复杂的配置，解决混乱的依赖关系。

### （2）SpringBoot的特点 ###

##### a. 可以创建独立的Spring应用程序，并且基于其Maven或Gradle插件，可以创建可执行的JARs和WARs #####

##### b. 内嵌Tomcat或Jetty等Servlet容器； #####

##### c. 提供自动配置的“starter”项目对象模型（POMS）以简化Maven配置； #####

##### d. 尽可能自动配置Spring容器； #####

##### e. 提供准备好的特性，如指标、健康检查和外部化配置； #####

##### f. 绝对没有代码生成，不需要XML配置 #####

## 二、SpringBoot使用 ##

### （1）属性注入配置文件 ###

*  **application.yaml**

inspur:
    	sms:
    		accessId: 123456
    		accessName: jack
    chaoyue:
    	system:
    		id: 123456
    		name: jack

*  **SmsProperties.java**

@Data
    @ConfigurationProperties(prefix="inspur.sms")
    public class SmsProperties{ 
    	private String accessId;
    	private String accessName;
    }

*  **SystemProperties.java**

@Data
    @ConfigurationProperties(prefix="chaoyue.system")
    public class SystemProperties{ 
    	private String id;
    	private String name;
    }

*  **SmsService.java**

@EnableConfigurationProperties({ SmsProperties.class, SystemProperties.class})
    public class SmsService{ 
    	@Autowired
    	private SmsProperties smsProperties;
    	
    	@Autowired
    	private SystemProperties systemProperties;
    
    	public void test(){ 
    		System.out.println(smsProperties.getAccessName());
    		System.out.println(systemProperties.getName());
    	}
    }

### （1）拦截器 ###

*  **MyInterceptor.java**

@Slf4j
    @Component
    public class MyInterceptor implements HandlerInterceptor { 
        @Override
        public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception { 
            log.info("前置方法正在执行");
            return true;
        }
    
        @Override
        public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception { 
            log.info("后置方法正在执行");
        }
    
        @Override
        public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception { 
            log.info("完成方法正在执行");
        }
    }

*  **MyInerceptorConfig.java**

@Configuration
    public class MyInerceptorConfig implements WebMvcConfigurer { 
    
        @Autowired
        private MyInterceptor myInterceptor;
    
        @Override
        public void addInterceptors(InterceptorRegistry registry) { 
            registry.addInterceptor(myInterceptor).addPathPatterns("/**");
        }
    }

## 三、SpringCloud介绍 ##

### （1）什么是SpringCloud ###

Spring Boot是一个用来搭建Spring应用的脚手架，为了简化复杂的配置，解决混乱的依赖关系。

### （2）SpringCloud的特点 ###

##### a. 可以创建独立的Spring应用程序，并且基于其Maven或Gradle插件，可以创建可执行的JARs和WARs #####

##### b. 内嵌Tomcat或Jetty等Servlet容器； #####

##### c. 提供自动配置的“starter”项目对象模型（POMS）以简化Maven配置； #####

##### d. 尽可能自动配置Spring容器； #####

##### e. 提供准备好的特性，如指标、健康检查和外部化配置； #####

##### f. 绝对没有代码生成，不需要XML配置 #####

## 二、SpringCloud使用 ##

### （1）注册中心Eureka ###

#### 注册中心 ####

*  **Eureka注册中心的EurekaServiceApplication.java**

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

*  **Eureka注册中心的application.yaml**

server:
      port: 8761
    spring:
      application:
        name: eureka-service
    eureka:
      client:
        service-url:
          defaultZone: http://192.168.0.198:8761/eureka, http://192.168.0.198:8762/eureka
        fetch-registry: false
      server:
      	enable-self-preservation: true # 开启自我保护状态
        eviction-interval-timer-in-ms: 10000 # 实现剔除时间
      instance:
        prefer-ip-address: true
        ip-address: 127.0.0.1

#### 服务提供方 ####

*  **服务提供方的ProviderApplication.java**

@SpringBootApplication
    @MapperScan("com.chaoyue.leyou.mapper")
    @EnableDiscoveryClient
    public class ProviderApplication { 
        public static void main(String[] args) { 
    
            SpringApplication.run(ProviderApplication.class, args);
        }
    }

*  **服务提供方的application.yaml**

server:
      port: 8081
    spring:
      application:
        name: service-provider
      datasource:
        url: jdbc:mysql://localhost:3306/heima
        password: 123456
        username: root
        driver-class-name: com.mysql.jdbc.Driver
    mybatis:
      type-aliases-package: com.chaoyue.leyou.pojo
    eureka:
      client:
        service-url:
          defaultZone: http://127.0.0.1:8761/eureka, http://127.0.0.1:8762/eureka
      instance:
        lease-renewal-interval-in-seconds: 5 # 服务续约时间间隔
        lease-expiration-duration-in-seconds: 15 # 服务失效时间间隔
        prefer-ip-address: true
        ip-address: 127.0.0.1

#### 服务消费方 ####

*  **服务消费方的ConsumerApplication.java**

@SpringBootApplication
    @EnableDiscoveryClient
    public class ConsumerApplication { 
        @Bean
        public RestTemplate restTemplate(){ 
            return new RestTemplate();
        };
    
        public static void main(String[] args) { 
    
            SpringApplication.run(ConsumerApplication.class, args);
        }
    }

*  **服务消费方的UserController.java**

@RestController
    public class UserController { 
        @Autowired
        private RestTemplate restTemplate;
    
        @Autowired
        private DiscoveryClient discoveryClient;
    
        @GetMapping("consumer/user/{id}")
        public User getUserById(@PathVariable("id") Long id) { 
            List<ServiceInstance> instances = discoveryClient.getInstances("SERVICE-PROVIDER");
            ServiceInstance instance = instances.get(0);
            String host = instance.getHost();
            int port = instance.getPort();
            return this.restTemplate.getForObject("http://" + host + ":" + port + "/user/" + id, User.class);
        }
    }

*  **服务消费方的application.yaml**

server:
      port: 8083
    spring:
      application:
        name: service-consumer
    eureka:
      client:
        service-url:
          defaultZone: http://127.0.0.1:8761/eureka, http://127.0.0.1:8762/eureka
        registry-fetch-interval-seconds: 5 # 拉取服务列表时间间隔
      instance:
        prefer-ip-address: true
        ip-address: 127.0.0.1

### （2）负载均衡器Ribbon ###

#### 服务消费方 ####

*  **服务消费方的ConsumerApplication.java**

@SpringBootApplication
    @EnableDiscoveryClient
    public class ConsumerApplication { 
        @Bean
        @LoadBalanced
        public RestTemplate restTemplate(){ 
            return new RestTemplate();
        };
    
        public static void main(String[] args) { 
    
            SpringApplication.run(ConsumerApplication.class, args);
        }
    }

*  **服务消费方的UserController.java**

@RestController
    public class UserController { 
        @Autowired
        private RestTemplate restTemplate;
    
        @GetMapping("consumer/user/{id}")
        public User getUserById(@PathVariable("id") Long id) { 
    
            return this.restTemplate.getForObject("http://service-provider/user/" + id, User.class);
        }
    }

*  **服务消费方的application.yaml**

### （3）熔断器Hystrix ###

#### 服务消费方 ####

*  **服务消费方的ConsumerApplication.java**

@SpringBootApplication
    @EnableDiscoveryClient
    @EnableCircuitBreaker
    public class ConsumerApplication { 
        @Bean
        @LoadBalanced
        public RestTemplate restTemplate(){ 
            return new RestTemplate();
        };
    
        public static void main(String[] args) { 
    
            SpringApplication.run(ConsumerApplication.class, args);
        }
    }

*  **服务消费方的UserController.java**

@RestController
    public class UserController { 
        @Autowired
        private RestTemplate restTemplate;
    
        @GetMapping("consumer/user/{id}")
        @HystrixCommand(fallbackMethod = "getUserByIdFallback")
        public User getUserById(@PathVariable("id") Long id) { 
    
            return this.restTemplate.getForObject("http://service-provider/user/" + id, User.class);
        }
    
        public User getUserByIdFallback(Long id) { 
            User user = new User();
            return user;
        }
    }

### （4）网关Zuul ###

*  **ZuulServiceApplication.java**

@SpringBootApplication
    @EnableZuulProxy
    @EnableDiscoveryClient
    public class ZuulServiceApplication { 
        public static void main(String[] args) { 
            SpringApplication.run(ZuulServiceApplication.class, args);
        }
    }

*  **application.yaml**

server:
      port: 5555
    spring:
      application:
        name: zuul-service
    eureka:
      client:
        service-url:
          defaultZone: http://127.0.0.1:8761/eureka, http://127.0.0.1:8762/eureka
        registry-fetch-interval-seconds: 5
      instance:
        lease-renewal-interval-in-seconds: 5 # 服务续约时间间隔
        lease-expiration-duration-in-seconds: 15 # 服务失效时间间隔
        prefer-ip-address: true
        ip-address: 127.0.0.1
    zuul:
      routes:
        service-consumer: /service-consumer/**
      prefix: /api
    hystrix:
      command:
        default:
          execution:
            isolation:
              thread:
                timeoutInMilliseconds: 6000

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