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UCloud云社区SpringCloud(第 039 篇)链接Mysql数据库,通过JpaRepository编写数据库访问

SpringCloud(第 039 篇)链接Mysql数据库,通过JpaRepository编写数据库访问

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一、大致介绍

1、本章节开始讲解一下访问数据库的操作,不过其实这还不算是SpringCloud的范畴,应该说是SpringBoot的操作范畴,这些就先抛开了,我们就还是讲解数据库的操作;
2、JpaRepository操作数据库访问,其实有许多同事都建议最好不要采用,因为我们平常的业务处理中并没有用到Jpa的额外的方法;
3、而且我也找了一篇文章提到了关于对JpaRepository的一些看法,链接地址为 http://jtuts.com/2014/08/26/difference-between-crudrepository-and-jparepository-in-spring-data-jpa;
4、而本章节我们仅仅只是讲解了一下如何集成操作Mysql数据库,采用JpaRepository来访问而已,不涉及什么深层次的业务;
5、另外配置文件中的mysql数据库配置,那么就得大家自己用自己的了哈;

Mysql数据库安装步骤

二、实现步骤
2.1 添加 maven 引用包

<?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>
    <artifactId>springms-provider-user-mysql-jparepository</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>jar</packaging>
    
    <parent>
        <groupId>com.springms.cloud</groupId>
        <artifactId>springms-spring-cloud</artifactId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    
    <dependencies>
        <!-- 访问数据库模块 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <!-- web模块 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <!-- MYSQL -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>
    </dependencies>
</project>

2.2 添加应用配置文件(springms-provider-user-mysql-jparepositorysrcmainresourcesapplication.yml)

server:
  port: 8310
spring:
  application:
    name: springms-provider-user-mysql-jparepository  #全部小写
#####################################################################################################
# mysql 属性配置
  datasource:
    driver-class-name: com.mysql.jdbc.Driver
    url: jdbc:mysql://ip:3306/hmilyylimh
    username: username
    password: password
  jpa:
    hibernate:
      #ddl-auto: create #ddl-auto:设为create表示每次都重新建表
      ddl-auto: update #ddl-auto:设为update表示每次都不会重新建表
    show-sql: true
#####################################################################################################
#####################################################################################################
# 打印日志
logging:
  level:
    root: INFO
    org.hibernate: INFO
    org.hibernate.type.descriptor.sql.BasicBinder: TRACE
    org.hibernate.type.descriptor.sql.BasicExtractor: TRACE
    com.springms: DEBUG
#####################################################################################################

2.3 添加访问底层数据模型的DAO接口(springms-provider-user-mysql-jparepository/src/main/java/com/springms/cloud/repository/UserRepository.java)

package com.springms.cloud.repository;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;
import com.springms.cloud.entity.User;
@Repository
public interface UserRepository extends JpaRepository<User, Long> {
}

2.4 添加实体用户类User(springms-provider-user-mysql-jparepository/src/main/java/com/springms/cloud/entity/User.java)

package com.springms.cloud.entity;
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 Integer age;
  @Column
  private String 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 Integer getAge() {
    return this.age;
  }
  public void setAge(Integer age) {
    this.age = age;
  }
  public String getBalance() {
    return this.balance;
  }
  public void setBalance(String balance) {
    this.balance = balance;
  }
}

2.5 添加用户Web访问层Controller(springms-provider-user-mysql-jparepository/src/main/java/com/springms/cloud/controller/ProviderUserMysqlController.java)

package com.springms.cloud.controller;
import com.springms.cloud.repository.UserRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;
import com.springms.cloud.entity.User;
import java.util.List;
/**
 * 用户微服务Controller。
 *
 * @author hmilyylimh
 *
 * @version 0.0.1
 *
 * @date 17/10/18
 *
 */
@RestController
public class ProviderUserMysqlController {
    @Autowired
    private UserRepository userRepository;
    @GetMapping("/simple/{id}")
    public User findUserById(@PathVariable Long id) {
        return this.userRepository.findOne(id);
    }
    @GetMapping("/simple/list")
    public List<User> findUserList() {
        return this.userRepository.findAll();
    }
    /**
     * 添加一个student,使用postMapping接收post请求
     *
     * http://localhost:8310/simple/addUser?username=user11&age=11&balance=11
     *
     * @return
     */
    @PostMapping("/simple/addUser")
    public User addUser(@RequestParam(value = "username", required=false) String username, @RequestParam(value = "age", required=false) Integer age, @RequestParam(value = "balance", required=false) String balance){
        User user=new User();
        user.setUsername(username);
        user.setName(username);
        user.setAge(age);
        user.setBalance(balance);
        return userRepository.save(user);
    }
}

2.6 添加用户微服务启动类(springms-provider-user-mysql-jparepository/src/main/java/com/springms/cloud/MsProviderUserMysqlApplication.java)

package com.springms.cloud;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
/**
 * 链接Mysql数据库,通过JpaRepository编写数据库访问。
 *
 * @author hmilyylimh
 *
 * @version 0.0.1
 *
 * @date 17/10/18
 *
 */
@SpringBootApplication
public class MsProviderUserMysqlApplication {
    public static void main(String[] args) {
        SpringApplication.run(MsProviderUserMysqlApplication.class, args);
        System.out.println("【【【【【【 链接Mysql数据库微服务 】】】】】】已启动.");
    }
}

三、测试

/****************************************************************************************
 一、链接Mysql数据库,通过JpaRepository编写数据库访问:
 1、启动 springms-provider-user-mysql-jparepository 模块服务,启动1个端口;
 2、在浏览器输入地址 http://localhost:8310/simple/10 可以看到用户ID=10的信息成功的被打印出来;
 3、使用 IDEA 自带工具 Test Restful WebService 发送 HTTP POST 请求,并添加 username、age、balance三个参数,然后执行请求,并去 mysql 数据库查看数据是否存在,正常情况下 mysql 数据库刚刚插入的数据成功了:
 4、使用 REST Client 执行 "/simple/list" 接口,也正常将 mysql 数据库中所有的用户信息打印出来了;
 ****************************************************************************************/

四、下载地址

https://gitee.com/ylimhhmily/SpringCloudTutorial.git

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