SpringCloud(第 040 篇)链接Mysql数据库,通过CrudRepository编写数据库访问
一、大致介绍
1、前面章节提到了用JpaRepository访问数据库,而本章节则是用CrudRepository访问数据,那么他们之间都可以访问数据库,有啥联系呢? 2、从源码我可知JpaRepository继承PagingAndSortingRepository,而PagingAndSortingRepository又继承CrudRepository,从这方面讲他们是子类与父类之间的关系; 3、而CrudRepository仅仅只是提供了最基本的数据库访问操作的方法,而JpaRepository在这些基础上还提供了一些更丰富的操作接口,但是在实际应用中大多数业务场景比较少用,但是还是有用的; 4、因此两者到底如何抉择的问题就来了,如果要我来选,我本人倾向于用CrudRepository,因为CrudRepository已经提供了基本的增删改查操作,而且这些基本满足我们绝大多数业务场景,我们不需要再增加额外的方法来操作数据库了; 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;
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-crudrepository</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-crudrepository\src\main\resources\application.yml)
server: port: 8320 spring: application: name: springms-provider-user-mysql-crudrepository #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-crudrepository/src/main/java/com/springms/cloud/repository/UserRepository.java)
package com.springms.cloud.repository; import org.springframework.data.repository.CrudRepository; import org.springframework.stereotype.Repository; import com.springms.cloud.entity.User; @Repository public interface UserRepository extends CrudRepository<User, Long> { }
2.4 添加实体用户类User(springms-provider-user-mysql-crudrepository/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-crudrepository/src/main/java/com/springms/cloud/controller/ProviderUserMysqlCrudRepoController.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; /** * 用户微服务Controller。 * * @author hmilyylimh * * @version 0.0.1 * * @date 17/10/18 * */ @RestController public class ProviderUserMysqlCrudRepoController { @Autowired private UserRepository userRepository; @GetMapping("/simple/{id}") public User findUserById(@PathVariable Long id) { return this.userRepository.findOne(id); } @GetMapping("/simple/list") public Iterable<User> findUserList() { return this.userRepository.findAll(); } /** * 添加一个student,使用postMapping接收post请求 * * http://localhost:8320/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-crudrepository/src/main/java/com/springms/cloud/MsProviderUserMysqlCrudRepoApplication.java)
package com.springms.cloud; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; /** * 链接Mysql数据库,通过CrudRepository编写数据库访问。 * * @author hmilyylimh * * @version 0.0.1 * * @date 17/10/18 * */ @SpringBootApplication public class MsProviderUserMysqlCrudRepoApplication { public static void main(String[] args) { SpringApplication.run(MsProviderUserMysqlCrudRepoApplication.class, args); System.out.println("【【【【【【 链接MysqlJpaCrud数据库微服务 】】】】】】已启动."); } }
三、测试
/**************************************************************************************** 一、链接Mysql数据库,通过CrudRepository编写数据库访问: 1、启动 springms-provider-user-mysql-crudrepository 模块服务,启动1个端口; 2、在浏览器输入地址 http://localhost:8320/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://git.oschina.net/ylimhhmily/SpringCloudTutorial.git
SpringCloudTutorial交流QQ群: 235322432
SpringCloudTutorial交流微信群: 微信沟通群二维码图片链接
欢迎关注,您的肯定是对我最大的支持!!!