springCloud--1

电影微服务是服务消费者，用户微服务是服务提供者。

Springcloud对eureka的支持很好，eureka本身是一个基于REST的服务，

Eureka里面有一个注册表，Application Client是服务消费者，Application Service是服务提供者。Make Remote Call是远程调用，us-east-1c,us-east-1d,us-east-1e是zone,他们都属于us-east-1这个region。他们都是Eureka Client。

服务提供者（Application Service）和服务消费者（Application Client）启动的时候都会像eureka注册（ip和端口），他们更eureka server有一个心跳机制默认30秒，连续3次90秒没有收到心跳就会从注册表移除这个节点。Eureka service集群之间会相互复制服务注册表。

服务提供者的ip和端口变化了，服务注册表会更新ip和端口。

eureka client缓存：即使所有的eureka service都宕机了，服务消费者也会知道服务提供者的ip和端口进行调用。

服务注册表就是一个数据库，用来记录ip和端口，并且提供API操作服务注册表，把服务添加到注册表称之为注册从注册表移除称之为注销。

心跳机制是健康检查机制。

服务发现方式：客户端发现（Eureka，zk），服务端发现（Consul+nginx）。http://blog.daocloud.io/microservices-4/   SpringCloud对Eureka支持最完整。

Eureka：服务发现组件。

服务消费者：

package com.itmuch.cloud;

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

//服务消费者
@SpringBootApplication
public class MicroserviceSimpleConsumerMovieApplication {

  @Bean //实例化了一个对象new RestTemplate，方法的名字rt就是实例化后bean的名字，其他地方通过@Autowired引用
  public RestTemplate rt() {
    return new RestTemplate();
  }

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

package com.itmuch.cloud.controller;

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

import com.itmuch.cloud.entity.User;

@RestController
public class MovieController {

  @Autowired  //初始化是启动类上面的@bean注解
  private RestTemplate rt;//使用RestTemplate调用

  //user: userServicePath: http://localhost:7900/simple/
  //从yml文件读值.这里的ip和端口是写死的，有的时候服务提供者的ip和端口是变化的。
  //如果有多个提供者，如何做负载（nginx是可以做转发的，nginx通过url转发到不同的微服务），使用eureka（客户端发现机制）。
  @Value("${user.userServicePath}")
  private String userServicePath;

  @GetMapping("/movie/{id}")
  public User findById(@PathVariable Long id) {
    return this.rt.getForObject(this.userServicePath + id, User.class);
  }
}

package com.itmuch.cloud.entity;

import java.math.BigDecimal;

public class User {
  private Long id;

  private String username;

  private String name;

  private Short age;

  private BigDecimal balance;

  public Long getId() {
    return this.id;
  }

  public void setId(Long id) {
    this.id = id;
  }

  public String getUsername() {
    return this.username;
  }

  public void setUsername(String username) {
    this.username = username;
  }

  public String getName() {
    return this.name;
  }

  public void setName(String name) {
    this.name = name;
  }

  public Short getAge() {
    return this.age;
  }

  public void setAge(Short age) {
    this.age = age;
  }

  public BigDecimal getBalance() {
    return this.balance;
  }

  public void setBalance(BigDecimal balance) {
    this.balance = balance;
  }

}

yml:

server:
  port: 7901
user:
  userServicePath: http://localhost:7900/simple/

pom.xml

<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.itmuch.cloud</groupId>
    <artifactId>microservice-simple-consumer-movie</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>microservice-simple-consumer-movie</name>
    <description>Demo project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.4.1.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <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>
        <dependency>
            <groupId>xalan</groupId>
            <artifactId>xalan</artifactId>
            <version>2.7.2</version>
        </dependency>
    </dependencies>

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

</project>

服务提供者：

package com.itmuch.cloud;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

//服务提供者
@SpringBootApplication
public class MicroserviceSimpleProviderUserApplication {

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

package com.itmuch.cloud.controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;

import com.itmuch.cloud.entity.User;
import com.itmuch.cloud.repository.UserRepository;

@RestController//相当于加了@responseBody和@controller
public class UserController {

  @Autowired
  private UserRepository userRepository;

  @GetMapping("/simple/{id}") //@GetMapping是@requestMapping(method=get)
  public User findById(@PathVariable Long id) {
    return this.userRepository.findOne(id);
  }
}

package com.itmuch.cloud.entity;

import java.math.BigDecimal;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;

@Entity
public class User {
  @Id
  @GeneratedValue(strategy = GenerationType.AUTO)
  private Long id;

  @Column
  private String username;

  @Column
  private String name;

  @Column
  private Short age;

  @Column
  private BigDecimal balance;

  public Long getId() {
    return this.id;
  }

  public void setId(Long id) {
    this.id = id;
  }

  public String getUsername() {
    return this.username;
  }

  public void setUsername(String username) {
    this.username = username;
  }

  public String getName() {
    return this.name;
  }

  public void setName(String name) {
    this.name = name;
  }

  public Short getAge() {
    return this.age;
  }

  public void setAge(Short age) {
    this.age = age;
  }

  public BigDecimal getBalance() {
    return this.balance;
  }

  public void setBalance(BigDecimal balance) {
    this.balance = balance;
  }
}

package com.itmuch.cloud.repository;

import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;

import com.itmuch.cloud.entity.User;

//DAO
@Repository
public interface UserRepository extends JpaRepository<User, Long> {

}

yml

server:
  port: 7900
spring:
  jpa:
    generate-ddl: false     #启动的时候不打印sql语句
    show-sql: true      #显示sql语句
    hibernate:    #依赖hibernate
      ddl-auto: none     #ddl语句的处理
  datasource:     #数据源
    platform: h2    #h2数据库
    schema: classpath:schema.sql  #建表语句
    data: classpath:data.sql    #数据
logging:
  level:
    root: INFO
    org.hibernate: INFO
    org.hibernate.type.descriptor.sql.BasicBinder: TRACE  #把参数打印出来
    org.hibernate.type.descriptor.sql.BasicExtractor: TRACE
    com.itmuch: DEBUG

data.sql:

insert into user(id,username, name, age, balance) values(1,'user1', '寮犱笁', 20, 100.00);
insert into user(id,username, name, age, balance) values(2,'user2', '鏉庡洓', 20, 100.00);
insert into user(id,username, name, age, balance) values(3,'user3', '鐜嬩簲', 20, 100.00);
insert into user(id,username, name, age, balance) values(4,'user4', '椹叚', 20, 100.00);

schema.sql

drop table user if exists;
create table user(
    id bigint generated by default as identity,
    username varchar(40),
    name varchar(20),
    age int(3),
    balance decimal(10,2),
    primary key(id)
);

<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.itmuch.cloud</groupId>
    <artifactId>microservice-simple-provider-user</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>microservice-simple-provider-user</name>
    <description>Demo project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.4.1.RELEASE</version>
        <relativePath/>
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>

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

        <dependency>
            <groupId>com.h2database</groupId>
            <artifactId>h2</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-solr</artifactId>
        </dependency>
    </dependencies>

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

</project>