我似乎无法从mySQL休眠以获取任何信息。我到处都看过书,我觉得自己做得对,很显然,我不是,但是我的大脑开始尝试理解自己的混乱状况。
主要:
@SpringBootApplication
@ComponentScan("com.luv2code")
@EntityScan("com.luv2code.entity")
@EnableJpaRepositories("com.luv2code.dao")
public class App {
public static void main(String[] args) {
SpringApplication.run(App.class, args);
}
}
控制器:
@Controller
public class CustomerController {
private CustomerDAO customerDAO;
@Autowired
public void setCustomerDAO(CustomerDAO customerDAO) {
this.customerDAO = customerDAO;
}
@RequestMapping("/")
public String listCustomers(Model model){
long test = customerDAO.count();
model.addAttribute("answer", test);
List<Customer> customers = customerDAO.findAll();
model.addAttribute("customers", customers);
return "home";
}
}
application.properties:
spring.datasource.url = jdbc:mysql://localhost:3306/web_customer_tracker?useSSL=false
spring.datasource.username=root
spring.datasource.password=metalgear3
spring.datasouce.driver-class-name=com.mysql.jdbc.Driver
spring.jpa.hibernate.ddl-auto=update
spring.jpa.hibernate.show-sql=true
spring.jpa.hibernate.dialect=org.hibernate.dialect.MySQL55Dialect
spring.jpa.properties.hibernate.current_session_context_class=org.springframework.orm.hibernate5.SpringSessionContext
entitymanager.packagesToScan = com.luv2code.entity.Customer
实体:
@Entity
@Table(name = "customer")
public class Customer implements Serializable {
@Column(name = "id")
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Id
private int id;
@Column(name = "first_name")
private String firstName;
@Column(name = "last_name")
private String lastName;
@Column(name = "email")
private String email;
public Customer(){}
@Override
public String toString() {
return "Customer{" +
"id=" + id +
", firstName='" + firstName + '\'' +
", lastName='" + lastName + '\'' +
", email='" + email + '\'' +
'}';
}
public Customer(String firstName, String lastName, String email){
this.firstName = firstName;
this.lastName = lastName;
this.email = email;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getFirstName() {
return firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
public String getLastName() {
return lastName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
}
DAO:
@Repository("CustomerDAO")
@Transactional
public interface CustomerDAO extends CrudRepository<Customer, Integer> {
public List<Customer> findAll();
public long count();
}
MySql的:
CREATE DATABASE IF NOT EXISTS `web_customer_tracker`;
USE `web_customer_tracker`;
DROP TABLE IF EXISTS `customer`;
CREATE TABLE `customer`(
`id` INT(11) NOT NULL auto_increment,
`first_name` VARCHAR(45) DEFAULT NULL,
`last_name` VARCHAR(45)DEFAULT NULL,
`email` VARCHAR(45) DEFAULT NULL,
PRIMARY KEY(`id`)
) ENGINE=INNODB AUTO_INCREMENT=1 CHARSET=latin1;
INSERT INTO `customer` VALUES
(1, 'David', 'Adams', '[email protected]'),
(2, 'John', 'Die', '[email protected]'),
(3, 'Ajay', 'Rao', '[email protected]'),
(4, 'Mary', 'Publiidc', '[email protected]'),
(5, 'Maxwell', 'Dixon', '[email protected]');
最佳答案
我知道现在答复有点晚了,但是这个问题对Google友好。
您无需在findAll()
内声明CustomerDAO
。接口CrudRepository
已经做到了。最重要的是,我建议改为实现JpaRepository
存储库(它扩展了CrudRepository
本身,并为您提供了更多免费的便捷方法。
关于java - CRUDRepository findAll查找为空,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/43564402/