第四章 SpringCloud之Eureka-Client实现服务(Jpa，H2)

1、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>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.3.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.test</groupId>
    <artifactId>eureka-client-user</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>eureka-client-user</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
        <spring-cloud.version>Greenwich.SR1</spring-cloud.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>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-server</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>
    </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>

2、在application.yml文件中添加配置

spring:
  application:
    name: eureka-client-user  #应用名
  jpa:
    generate-ddl: false
    show-sql: true   #jpa显示sql语句
    hibernate:
      ddl-auto: none
  datasource:
    platform: h2   #数据库使用H2模拟
    schema: classpath:schema.sql  #sql语句配置
    data: classpath:data.sql  #数据配置
logging:  #logging日志配置
  level:
    root: INFO
    org.hibernate: INFO
server:
  port: 8663   #服务端口

eureka:
  instance:
    hostname: localhost
    prefer-ip-address: true
    instance-id: ${spring.application.name}:${spring.application.instance_id:${server.port}}
  client:
    serviceUrl:
      defaultZone: http://${eureka.instance.hostname}:8661/eureka

3、在启动类添加注解

package com.test.eurekaclientuser;

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

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

4、添加data.sql和schema.sql

#schema.sql文件内容
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))

#data.sql文件内容
insert into user (id,username,name,age,balance) values(1,'user1','zhangsan',20,100.00);
insert into user (id,username,name,age,balance) values(2,'user2','zhangsan',20,100.00);
insert into user (id,username,name,age,balance) values(3,'user3','zhangsan',20,100.00);
insert into user (id,username,name,age,balance) values(4,'user4','zhangsan',20,100.00);
insert into user (id,username,name,age,balance) values(5,'user5','zhangsan',20,100.00);

5、User.java类

package com.test.eurekaclientuser.entity;

import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
import javax.persistence.*;
import java.io.Serializable;
import java.math.BigDecimal;
//Jpa的注解配置
@Entity
@JsonIgnoreProperties(value = { "hibernateLazyInitializer", "handler" })
public class User implements Serializable {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private  Long id;
    @Column
    private  String name;
    @Column
    private  String username;
    @Column
    private  BigDecimal balance;
    @Column
    private  short age;

    public Long getId() {
        return id;
    }

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

    public String getName() {
        return name;
    }

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

    public String getUsername() {
        return username;
    }

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

    public BigDecimal getBalance() {
        return balance;
    }

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

    public short getAge() {
        return age;
    }

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

6、UserRepository.java类

package com.test.eurekaclientuser.repository;

import com.test.eurekaclientuser.entity.User;
import org.springframework.data.jpa.repository.JpaRepository;
#继承Jpa的类
public interface UserRepository extends JpaRepository<User,Long> {
}

7、UserController.java类

package com.test.eurekaclientuser.controller;

import com.test.eurekaclientuser.entity.User;
import com.test.eurekaclientuser.repository.UserRepository;
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;

@RestController
public class UserController {
    @Autowired
    private UserRepository userRepository;

  /*  @Autowired
    private EurekaClient discoveryClient;*/

    @GetMapping("/user/{id}")
    public User findById(@PathVariable  Long id){
        System.out.println(id);
        return this.userRepository.getOne(id);
    }

   /* @GetMapping("/eureka/url")
    public String serviceUrl() {
        InstanceInfo instance = discoveryClient.getNextServerFromEureka("client1", false);
        return instance.getHomePageUrl();
    }*/
}

8、访问URL

http://localhost:8663/user/1

同时，可以在eureka-server组件上看到注册的信息，即