值不值 | 三分钟搞定Jpa？值不值！
本文转载自微信公众号「小明菜市场」，值不值分钟搞值不值作者+小明菜市场。值不值分钟搞值不值转载本文请联系小明菜市场公众号。值不值分钟搞值不值
数据准备
数据库使用的值不值分钟搞值不值数据表设计如下
建表语句如下
SET NAMES utf8mb4; SET FOREIGN_KEY_CHECKS = 0; -- ---------------------------- -- Table structure for t_user -- ---------------------------- DROP TABLE IF EXISTS `t_user`; CREATE TABLE `t_user` ( `id` int(11) NOT NULL AUTO_INCREMENT, `user_name` varchar(255) DEFAULT NULL, `password` varchar(255) DEFAULT NULL, `last_login_time` datetime DEFAULT NULL, `sex` tinyint(4) DEFAULT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB AUTO_INCREMENT=6 DEFAULT CHARSET=armscii8; -- ---------------------------- -- Records of t_user -- ---------------------------- BEGIN; INSERT INTO `t_user` VALUES (1, json, 123, 2019-07-27 16:01:21, 1); INSERT INTO `t_user` VALUES (2, jack jo, 123, 2019-07-24 16:01:37, 1); INSERT INTO `t_user` VALUES (3, manistal, 123, 2019-07-24 16:01:37, 1); INSERT INTO `t_user` VALUES (4, landengdeng, 123, 2019-07-24 16:01:37, 1); INSERT INTO `t_user` VALUES (5, max, 123, 2019-07-24 16:01:37, 1); COMMIT; SET FOREIGN_KEY_CHECKS = 1;新建 Spring Boot 工程
选择 File -> New -> Project 选择 Spring Initializr，选择 next 填写包名，值不值分钟搞值不值项目名，值不值分钟搞值不值选择下一步。值不值分钟搞值不值选择依赖，值不值分钟搞值不值Spring web starter 前面打钩，值不值分钟搞值不值sql 选项为 Spring Data Jpa，值不值分钟搞值不值MySql 项目名任意
引入 Pom配置
<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-webflux</artifactId> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <scope>runtime</scope> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> <dependency> <groupId>io.projectreactor</groupId> <artifactId>reactor-test</artifactId> <scope>test</scope> </dependency> </dependencies>编写配置文件 application.yml
server: port: 8086 spring: #通用的值不值分钟搞值不值数据源配置 datasource: driverClassName: com.mysql.jdbc.Driver url: jdbc:mysql://localhost:3306/demo_test?useSSL=false&useUnicode=true&characterEncoding=utf8 username: root password: 123 jpa: #这个参数是服务器托管在建表的时候，将默认的值不值分钟搞值不值存储引擎切换为 InnoDB 用的 database-platform: org.hibernate.dialect.MySQL5InnoDBDialect #配置在日志中打印出执行的 SQL 语句信息。 show-sql: true hibernate: #配置指明在程序启动的值不值分钟搞值不值时候要删除并且创建实体类对应的表 ddl-auto: create编写示例代码
新建实体对象 UserDao.java
实体类，需要使用 @Entity 注解标注 需要对实体类的值不值分钟搞值不值属性进行标注，使用 @Id 标注组件 使用 @Column 标注非主键
/** * 用户实体类 * */ @Entity @Table(name="t_user") public class UserDO { @Id private Integer id; @Column(name="user_name",值不值分钟搞值不值length = 200) private String userName; @Column(name="password",length = 200) private String password; @Column(name="sex") private Integer sex; @Column(name="last_login_time") private Date lastLoginTime; public Integer getId() { return id; } public void setId(Integer id) { this.id = id; } public String getUserName() { return userName; } public void setUserName(String userName) { this.userName = userName; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } public Integer getSex() { return sex; } public void setSex(Integer sex) { this.sex = sex; } public Date getLastLoginTime() { return lastLoginTime; } public void setLastLoginTime(Date lastLoginTime) { this.lastLoginTime = lastLoginTime; } }新建仓库接口类 UserRepository
仓库接口类，云服务器UserRepository 是我们常用的 Dao 接口，需要注意
使用 @Repository 注解 继承 JPARepository UserRepository 不需要编写任何代码，即可实现增删查改 @Repository public interface UserRepository extends JPARepository<UserDO,Integer> { }编写测试用例
在
src/test/java/com/fishpro/jpa/下，新增加
UserRepositoryTest.java使用
@RunWith(SpringRunner.class)和
@SpringBootTest注解标注类。
@RunWith(SpringRunner.class) @SpringBootTest public class UserRepositoryTest{ }新增加用户数据
/** * 初始化一个对象 UserDO 测试Insert过程 * */ @Before public void before(){ UserDO userDO=new UserDO(); userDO.setId(1); userDO.setUserName("fishpro"); userDO.setSex(1); userDO.setLastLoginTime(new Date()); userDO.setPassword("passWord"); userRepository.save(userDO); }查询单个用户数据
@Test public void testFind(){ Optional<UserDO> optionalUserDO=userRepository.findById(1); if(optionalUserDO.isPresent()){ UserDO userDO=optionalUserDO.get(); System.out.println("testFind user"+userDO.getUserName()); } }查询多个数据
@Test public void testFindAll(){ List<UserDO> list=userRepository.findAll(); for (UserDO user:list ) { System.out.println("user_name:"+user.getUserName()); } }更新数据
@Test public void testUpdate(){ Optional<UserDO> optionalUserDO=userRepository.findById(1); if(optionalUserDO.isPresent()){ UserDO userDO=optionalUserDO.get(); userDO.setUserName("fishpro001"); userRepository.save(userDO); System.out.println("testFind user"+userDO.getUserName()); } }删除数据
@After public void after(){ userRepository.deleteById(1); userRepository.deleteById(2); userRepository.deleteById(3); }联合主键
例如定义表中userId，roleId 都是主键，此时这样设置
1.定义一个主键类
public class UserRoleKey implements Serializable { private Integer userId; private Integer roleId; }2.定义实体类
@Entity @Table(name="t_user_role") @IdClass(UserRoleKey.class) //注意这里是引入了 定义的符合主键类 public class UserRoleDO { @Id private Integer userId; @Id private Integer roleId; public Integer getUserId() { return userId; } public void setUserId(Integer userId) { this.userId = userId; } public Integer getRoleId() { return roleId; } public void setRoleId(Integer roleId) { this.roleId = roleId; } } 源码下载