Spring Boot Dao和JpaRepositories在@Autowiring时抛出NullPointerException

7dl7o3gd  于 2023-11-17  发布在  Spring
关注(0)|答案(1)|浏览(176)

问题：

自动装配SingerDaoImpl和JpaRepositoryImpl Bean会导致null结果。不会抛出Exception，但不会返回Data。使用Thymeleaf视图显示数据

采用的技术：

Spring、JpaRepository、Hibernate、Thymeleaf、H2 Embedded DB（脚本位于resources/SQL文件夹中）、Spring MVC、javax. validation。
我使用localhost：8080/songers通过位于resources/templates/listSingers.html中的thymeleaf列出歌手。

我划掉的东西：

  • 没有使用new运算符声明@Component（或其专门化）Class
  • 所有@Autowired的bean都使用@Component、@Repository或@Service进行注解
  • 二传手已经就位，
  • @ browser已经指向了正确的bean
  • 嵌入式数据库使用位于resources/SQL/test.sql中的数据填充，并通过DBConfig.java类使用EmbeddedDatabaseBuilder.addScript（“SQL/test.sql”）方法添加
  • gradle.build文件版本中的所有依赖项均由gradle管理为最新版本

github页面链接：

https://github.com/NikitaDyagilev/LearningSprinbMVC
注意：我正在使用Amazon Corretto Java 11

DBConfig.java

  1. package com.example.demo.Config;
  3. @Configuration
  4. @ComponentScan
  5. @EnableJpaRepositories(basePackages = {"com.example.demo.JpaRepo"})
  6. @PropertySource("classpath:application.properties")
  7. public class DBconfig {
  9.      @Value("${jdbc.driverClassName}")
  10.      private String driverClassName;
  11.      @Value("${jdbc.username}")
  12.      private String username;
  13.      @Value("${jdbc.password}")
  14.      private String password;
  15.      @Value("${jdbc.url}")
  16.      private String url;
  18.      private Logger logger = LoggerFactory.getLogger(DBconfig.class);
  20. //   MySQL DataSource Connection
  21.      @Bean
  22.      public DataSource dataSourceR(){
  23.           try{
  24.                SimpleDriverDataSource db =
  25.                        new SimpleDriverDataSource();
  26.                Class<? extends Driver> driver =
  27.                        (Class<? extends Driver>) Class.forName(driverClassName);
  28.                db.setDriverClass(driver);
  29.                db.setUsername(username);
  30.                db.setPassword(password);
  31.                db.setUrl(url);
  32.                return db;
  33.           } catch (Exception e){
  34.                logger.error("Something Went wrong when trying to Create the MySQL DataSource bean");
  35.                return null;
  36.           }
  37.      }
  39. //   Embedded DataSource Connection
  40.      @Bean
  41.      public DataSource dataSourceE(){
  42.           try{
  43.                EmbeddedDatabaseBuilder db =
  44.                        new EmbeddedDatabaseBuilder();
  45.                db.setType(EmbeddedDatabaseType.H2);
  46.                db.addScript("SQL/table.sql");
  47.                db.addScript("SQL/test.sql");
  48.                return db.build();
  49.           } catch (Exception e ){
  50.                logger.error("There was an error when trying to create Embeded DataSource: ", e);
  51.                return null;
  52.           }
  53.      }
  55.      @Bean
  56.      public Properties hibernaProperties(){
  57.           Properties prop = new Properties();
  58.           prop.put("hibernate.dialect", "org.hibernate.dialect.H2Dialect");
  59. //          prop.put("hibernate.dialect", "org.hibernate.dialect.MySQL8Dialect");
  60.           prop.put("hibernate.hbm2ddl.auto", "create-drop");
  61.           prop.put("hibernate.format_sql", true);
  62.           prop.put("hibernate.show_sql", true);
  63.           prop.put("hibernate.max_fetch_depth", 3);
  64.           prop.put("hibernate.jdbc.batch_size", 10);
  65.           prop.put("hibernate.jdbc.fetch_size", 50);
  66.           return prop;
  67.      }
  69.      @Bean
  70.      public PlatformTransactionManager transactionManager(){
  71.           return new JpaTransactionManager(entityManagerFactory());
  72.      }
  74.      @Bean
  75.      public JpaVendorAdapter jpaVendorAdapter(){
  76.           return new HibernateJpaVendorAdapter();
  77.      }
  79.      @Bean(name ="entityManagerFactory")
  80.      public EntityManagerFactory entityManagerFactory(){
  81.           LocalContainerEntityManagerFactoryBean emfb =
  82.                   new LocalContainerEntityManagerFactoryBean();
  83.           emfb.setDataSource(dataSourceE());
  84.           emfb.setPackagesToScan("com.example.demo.Model");
  85.           emfb.setJpaVendorAdapter(new HibernateJpaVendorAdapter());
  86.           emfb.setJpaProperties(hibernaProperties());
  87.           emfb.setJpaVendorAdapter(jpaVendorAdapter());
  88.           emfb.afterPropertiesSet();
  89.           return emfb.getObject();
  90.      }
  91. }

字符串

控制器类

  1. package com.example.demo.Controllers;
  3. import java.util.List;
  5. @Controller
  6. public class TestController {
  8.     private Logger logger = LoggerFactory.getLogger(TestController.class);
  10.     private SingerDao dao;
  12.     @GetMapping(value = "/hello")
  13.     @ResponseBody
  14.     public String sayHello(){
  15.         return "Hello There";
  16.     }
  18.     @GetMapping(value ="/homepage")
  19.     public String homepageListing(){
  20.         return "homepage";
  21.     }
  23.     @GetMapping(value="/singers")
  24.     public String listSingers(Model model){
  25.         logger.info("Listing Singers:");
  26.         List<Singer> singers = dao.findAll();
  27.         String[] names = new String[singers.size()];
  28.         for(int i = 0; i < names.length; i++){
  29.             names[i] = singers.get(i).getFirstName();
  30.         }
  31.         model.addAttribute("singersNames", names);
  32.         return "ListSingers";
  33.     }
  35.     @GetMapping(value="/getSinger{id}")
  36.     public String getSingerById(Model model,@PathVariable Long id){
  37.         model.addAttribute("singer", dao.findById(id).getFirstName());
  38.         return "getSinger";
  39.     }
  41.     @Autowired
  42.     public void setDao(SingerDao dao) {
  43.         this.dao = dao;
  44.     }
  45. }

型

Jpa仓库

  1. package com.example.demo.JpaRepo;
  3. @Repository("jpaRepositoryImpl")
  4. public class JpaRepositoryImpl implements JpaRepository {
  5.     private EntityManagerFactory emf;
  7.     @Override
  8.     public List<Singer> findAll() {
  9.         return emf.createEntityManager()
  10.                 .createQuery("select s from singer s")
  11.                 .getResultList();
  12.     }
  14.     @Override
  15.     public Optional<Singer> findById(Long aLong) {
  16.         return (Optional<Singer>) emf.createEntityManager().createQuery("select s from singer s where s.id = ?id").
  17.                 setParameter("id",aLong).getSingleResult();
  18.     }
  20.     @Autowired
  21.     @Qualifier(value = "entityManagerFactory")
  22.     public void setEmf(EntityManagerFactory emf) {
  23.         this.emf = emf;
  24.     }
  25. }

型

DAO服务

  1. package com.example.demo.DAO;
  3. @Service("singerDaoImpl")
  4. public class SingerDaoImpl implements SingerDao {
  6.     private JpaRepository jpaRepo;
  8.     @Override
  9.     public List<Singer> findAll() {
  10.         List<Singer> singers = new ArrayList<>();
  11.         jpaRepo.findAll().forEach(item -> singers.add(item));
  12.         System.out.println("# Of Singers: "+singers.size());
  13.         return singers;
  14.     }
  16.     @Override
  17.     public Singer findById(Long id) {
  18.         return null;
  19.     }
  21.     @Autowired
  22.     @Qualifier(value="jpaRepositoryImpl")
  23.     public void setJpaRepo(JpaRepository jpaRepo) {
  24.         this.jpaRepo = jpaRepo;
  25.     }
  26. }

型

型号

  1. package com.example.demo.Model;
  3. @Table(name="singer")
  4. @Entity(name="singer")
  5. public class Singer implements Serializable{
  7.      @Id
  8.      @GeneratedValue(strategy = GenerationType.IDENTITY)
  9.      @Column(name="id")
  10.      private Long id;
  12.      @NotEmpty(message = "{validation.firstname.NotEmpty.message}")
  13.      @Size(min=3,max=60,message="{validation.firstname.Size.message}")
  14.      @Column(name="first_name")
  15.      private String firstName;
  17.      @NotEmpty(message = "{validation.lastname.NotEmpty.message}")
  18.      @Size(min=3,max=60,message ="{validation.lastname.Size.message")
  19.      @Column(name="last_name")
  20.      private String lastName;
  22.      @Temporal(TemporalType.DATE)
  23.      @Column(name="birth_date")
  24.      private Date birthDate;
  26.      @Column(name="description")
  27.      private String description;
  29.      @Basic(fetch=FetchType.LAZY)
  30.      @Lob
  31.      @Column(name="photo")
  32.      private byte photo;
  34.      public Long getId() {
  35.           return id;
  36.      }
  38.      public void setId(Long id) {
  39.           this.id = id;
  40.      }
  42.      public String getFirstName() {
  43.           return firstName;
  44.      }
  46.      public void setFirstName(String firstName) {
  47.           this.firstName = firstName;
  48.      }
  50.      public String getLastName() {
  51.           return lastName;
  52.      }
  54.      public void setLastName(String lastName) {
  55.           this.lastName = lastName;
  56.      }
  58.      public Date getDate() {
  59.           return birthDate;
  60.      }
  62.      public void setDate(Date date) {
  63.           this.birthDate = date;
  64.      }
  66.      public String getDescription() {
  67.           return description;
  68.      }
  70.      public void setDescription(String description) {
  71.           this.description = description;
  72.      }
  74.      public byte getPhoto() {
  75.           return photo;
  76.      }
  78.      public void setPhoto(byte photo) {
  79.           this.photo = photo;
  80.      }
  82.      @Transient
  83.      public String getBirthDateString(){
  84.           String birthDateString = "";
  85.           if(birthDate != null){
  86.                SimpleDateFormat sdf = new SimpleDateFormat("yyy-MM-dd");
  87.                     birthDateString = sdf.format(birthDate);
  88.           }
  89.           return birthDateString;
  90.      }
  92.      @Override
  93.      public String toString() {
  94.           return "Singer{" +
  95.                   "id=" + id +
  96.                   ", firstName='" + firstName + '\'' +
  97.                   ", lastName='" + lastName + '\'' +
  98.                   ", birthDate=" + birthDate +
  99.                   ", description='" + description + '\'' +
  100.                   ", photo=" + photo +
  101.                   '}';
  102.      }
  103. }

型

  • 编辑：* 我添加了logging.level.org.springframework = debug

下面是控制台的相关部分

  1. 2020-05-26 11:26:13.500  INFO 14664 --- [           main] o.s.web.context.ContextLoader            : Root WebApplicationContext: initialization completed in 2935 ms
  2. 2020-05-26 11:26:13.508 DEBUG 14664 --- [           main] o.s.b.f.s.DefaultListableBeanFactory     : Creating shared instance of singleton bean 'requestContextFilter'
  3. 2020-05-26 11:26:13.513 DEBUG 14664 --- [           main] o.s.b.f.s.DefaultListableBeanFactory     : Creating shared instance of singleton bean 'formContentFilter'
  4. 2020-05-26 11:26:13.513 DEBUG 14664 --- [           main] o.s.b.f.s.DefaultListableBeanFactory     : Creating shared instance of singleton bean 'org.springframework.boot.autoconfigure.web.servlet.WebMvcAutoConfiguration'
  5. 2020-05-26 11:26:13.519 DEBUG 14664 --- [           main] o.s.b.f.s.DefaultListableBeanFactory     : Creating shared instance of singleton bean 'characterEncodingFilter'
  6. 2020-05-26 11:26:13.531 DEBUG 14664 --- [           main] o.s.b.w.s.ServletContextInitializerBeans : Mapping filters: characterEncodingFilter urls=[/*] order=-2147483648, formContentFilter urls=[/*] order=-9900, requestContextFilter urls=[/*] order=-105
  7. 2020-05-26 11:26:13.532 DEBUG 14664 --- [           main] o.s.b.w.s.ServletContextInitializerBeans : Mapping servlets: dispatcherServlet urls=[/]
  8. 2020-05-26 11:26:13.565 DEBUG 14664 --- [           main] o.s.b.w.s.f.OrderedRequestContextFilter  : Filter 'requestContextFilter' configured for use
  9. 2020-05-26 11:26:13.565 DEBUG 14664 --- [           main] s.b.w.s.f.OrderedCharacterEncodingFilter : Filter 'characterEncodingFilter' configured for use
  10. 2020-05-26 11:26:13.566 DEBUG 14664 --- [           main] o.s.b.w.s.f.OrderedFormContentFilter     : Filter 'formContentFilter' configured for use
  11. 2020-05-26 11:26:13.585 DEBUG 14664 --- [           main] o.s.b.f.s.DefaultListableBeanFactory     : Creating shared instance of singleton bean 'demoApplication'
  12. 2020-05-26 11:26:13.586 DEBUG 14664 --- [           main] o.s.b.f.s.DefaultListableBeanFactory     : Creating shared instance of singleton bean 'DBconfig'
  13. 2020-05-26 11:26:13.591 DEBUG 14664 --- [           main] o.s.c.e.PropertySourcesPropertyResolver  : Found key 'jdbc.driverClassName' in PropertySource 'applicationConfig: [classpath:/application.properties]' with value of type String
  14. 2020-05-26 11:26:13.591 DEBUG 14664 --- [           main] o.s.c.e.PropertySourcesPropertyResolver  : Found key 'jdbc.driverClassName' in PropertySource 'environmentProperties' with value of type String
  15. 2020-05-26 11:26:13.593 DEBUG 14664 --- [           main] o.s.c.e.PropertySourcesPropertyResolver  : Found key 'jdbc.username' in PropertySource 'configurationProperties' with value of type String
  16. 2020-05-26 11:26:13.593 DEBUG 14664 --- [           main] o.s.c.e.PropertySourcesPropertyResolver  : Found key 'jdbc.username' in PropertySource 'environmentProperties' with value of type String
  17. 2020-05-26 11:26:13.595 DEBUG 14664 --- [           main] o.s.c.e.PropertySourcesPropertyResolver  : Found key 'jdbc.password' in PropertySource 'configurationProperties' with value of type String
  18. 2020-05-26 11:26:13.595 DEBUG 14664 --- [           main] o.s.c.e.PropertySourcesPropertyResolver  : Found key 'jdbc.password' in PropertySource 'environmentProperties' with value of type String
  19. 2020-05-26 11:26:13.595 DEBUG 14664 --- [           main] o.s.c.e.PropertySourcesPropertyResolver  : Found key 'jdbc.url' in PropertySource 'configurationProperties' with value of type String
  20. 2020-05-26 11:26:13.595 DEBUG 14664 --- [           main] o.s.c.e.PropertySourcesPropertyResolver  : Found key 'jdbc.url' in PropertySource 'environmentProperties' with value of type String
  21. 2020-05-26 11:26:13.599 DEBUG 14664 --- [           main] o.s.b.f.s.DefaultListableBeanFactory     : Creating shared instance of singleton bean 'testController'
  22. 2020-05-26 11:26:13.607 DEBUG 14664 --- [           main] o.s.b.f.s.DefaultListableBeanFactory     : Creating shared instance of singleton bean 'singerDaoImpl'
  23. 2020-05-26 11:26:13.614 DEBUG 14664 --- [           main] o.s.b.f.s.DefaultListableBeanFactory     : Creating shared instance of singleton bean 'jpaRepositoryImpl'
  24. 2020-05-26 11:26:13.621 DEBUG 14664 --- [           main] o.s.b.f.s.DefaultListableBeanFactory     : Creating shared instance of singleton bean 'entityManagerFactory'
  25. 2020-05-26 11:26:13.673 DEBUG 14664 --- [           main] o.s.b.f.s.DefaultListableBeanFactory     : Creating shared instance of singleton bean 'dataSourceE'
  26. 2020-05-26 11:26:13.702  INFO 14664 --- [           main] o.s.j.d.e.EmbeddedDatabaseFactory        : Starting embedded database: url='jdbc:h2:mem:testdb;DB_CLOSE_DELAY=-1;DB_CLOSE_ON_EXIT=false', username='sa'
  27. 2020-05-26 11:26:13.712 DEBUG 14664 --- [           main] o.s.jdbc.datasource.DataSourceUtils      : Fetching JDBC Connection from DataSource
  28. 2020-05-26 11:26:13.713 DEBUG 14664 --- [           main] o.s.j.datasource.SimpleDriverDataSource  : Creating new JDBC Driver Connection to [jdbc:h2:mem:testdb;DB_CLOSE_DELAY=-1;DB_CLOSE_ON_EXIT=false]
  29. 2020-05-26 11:26:13.971 DEBUG 14664 --- [           main] o.s.jdbc.datasource.init.ScriptUtils     : Executing SQL script from class path resource [SQL/table.sql]
  30. 2020-05-26 11:26:14.002 DEBUG 14664 --- [           main] o.s.jdbc.datasource.init.ScriptUtils     : 0 returned as update count for SQL: CREATE TABLE SINGER ( ID INT NOT NULL AUTO_INCREMENT, FIRST_NAME VARCHAR(60), LAST_NAME VARCHAR(40), BIRTH_DATE DATE, DESCRIPTION VARCHAR(2000) NULL, PHOTO BLOB NULL, VERSION INT NOT NULL DEFAULT 0, UNIQUE UQ_SINGER_1 (FIRST_NAME, LAST_NAME), PRIMARY KEY (ID) )
  31. 2020-05-26 11:26:14.002 DEBUG 14664 --- [           main] o.s.jdbc.datasource.init.ScriptUtils     : Executed SQL script from class path resource [SQL/table.sql] in 30 ms.
  32. 2020-05-26 11:26:14.002 DEBUG 14664 --- [           main] o.s.jdbc.datasource.init.ScriptUtils     : Executing SQL script from class path resource [SQL/test.sql]
  33. 2020-05-26 11:26:14.014 DEBUG 14664 --- [           main] o.s.jdbc.datasource.init.ScriptUtils     : 1 returned as update count for SQL: INSERT INTO SINGER (FIRST_NAME, LAST_NAME, BIRTH_DATE) VALUES ('John', 'Mayer', '1977-10-16')
  34. 2020-05-26 11:26:14.014 DEBUG 14664 --- [           main] o.s.jdbc.datasource.init.ScriptUtils     : 1 returned as update count for SQL: INSERT INTO SINGER (FIRST_NAME, LAST_NAME, BIRTH_DATE) VALUES ('Eric', 'Clampton', '1954-03-20')
  35. 2020-05-26 11:26:14.017 DEBUG 14664 --- [           main] o.s.jdbc.datasource.init.ScriptUtils     : 1 returned as update count for SQL: INSERT INTO SINGER (FIRST_NAME, LAST_NAME, BIRTH_DATE) VALUES ('John', 'Butler', '1975-04-01')
  36. 2020-05-26 11:26:14.017 DEBUG 14664 --- [           main] o.s.jdbc.datasource.init.ScriptUtils     : 1 returned as update count for SQL: INSERT INTO SINGER (FIRST_NAME, LAST_NAME, BIRTH_DATE) VALUES ('B.B' , 'King', '1925-09-16')
  37. 2020-05-26 11:26:14.019 DEBUG 14664 --- [           main] o.s.jdbc.datasource.init.ScriptUtils     : 1 returned as update count for SQL: INSERT INTO SINGER (FIRST_NAME, LAST_NAME, BIRTH_DATE) VALUES ('Jimi', 'Hendrix', '1942-11-27')
  38. 2020-05-26 11:26:14.021 DEBUG 14664 --- [           main] o.s.jdbc.datasource.init.ScriptUtils     : 1 returned as update count for SQL: INSERT INTO SINGER (FIRST_NAME, LAST_NAME, BIRTH_DATE) VALUES ('Eddie', 'Van Halen','1955-01-26')
  39. 2020-05-26 11:26:14.022 DEBUG 14664 --- [           main] o.s.jdbc.datasource.init.ScriptUtils     : 1 returned as update count for SQL: INSERT INTO SINGER (FIRST_NAME, LAST_NAME, BIRTH_DATE) VALUES ('Saul Slash', 'Hudson', '1965-07-23')
  40. 2020-05-26 11:26:14.023 DEBUG 14664 --- [           main] o.s.jdbc.datasource.init.ScriptUtils     : 1 returned as update count for SQL: INSERT INTO SINGER (FIRST_NAME, LAST_NAME, BIRTH_DATE) VALUES ('Stevie', 'Ray Vaughan','1954-10-03')
  41. 2020-05-26 11:26:14.023 DEBUG 14664 --- [           main] o.s.jdbc.datasource.init.ScriptUtils     : 1 returned as update count for SQL: INSERT INTO SINGER (FIRST_NAME, LAST_NAME, BIRTH_DATE) VALUES ('David', 'Gilmour','1946-03-06')
  42. 2020-05-26 11:26:14.026 DEBUG 14664 --- [           main] o.s.jdbc.datasource.init.ScriptUtils     : 1 returned as update count for SQL: INSERT INTO SINGER (FIRST_NAME, LAST_NAME, BIRTH_DATE) VALUES ('Kirk','Hammett','1992-11-18')
  43. 2020-05-26 11:26:14.027 DEBUG 14664 --- [           main] o.s.jdbc.datasource.init.ScriptUtils     : 1 returned as update count for SQL: INSERT INTO SINGER (FIRST_NAME, LAST_NAME, BIRTH_DATE) VALUES ('Angus','Young','1955-03-31')
  44. 2020-05-26 11:26:14.028 DEBUG 14664 --- [           main] o.s.jdbc.datasource.init.ScriptUtils     : 1 returned as update count for SQL: INSERT INTO SINGER (FIRST_NAME, LAST_NAME, BIRTH_DATE) VALUES ('Dimebad','Darrell','1966-08-20')
  45. 2020-05-26 11:26:14.029 DEBUG 14664 --- [           main] o.s.jdbc.datasource.init.ScriptUtils     : 1 returned as update count for SQL: INSERT INTO SINGER (FIRST_NAME, LAST_NAME, BIRTH_DATE) VALUES ('Carlos','Santana','1947-07-20')
  46. 2020-05-26 11:26:14.030 DEBUG 14664 --- [           main] o.s.jdbc.datasource.init.ScriptUtils     : Executed SQL script from class path resource [SQL/test.sql] in 28 ms.
  47. 2020-05-26 11:26:14.039 DEBUG 14664 --- [           main] o.s.b.f.s.DefaultListableBeanFactory     : Creating shared instance of singleton bean 'org.springframework.boot.autoconfigure.jdbc.DataSourceInitializerInvoker'
  48. 2020-05-26 11:26:14.043 DEBUG 14664 --- [           main] o.s.b.f.s.DefaultListableBeanFactory     : Creating shared instance of singleton bean 'spring.datasource-org.springframework.boot.autoconfigure.jdbc.DataSourceProperties'
  49. 2020-05-26 11:26:14.064 DEBUG 14664 --- [           main] o.s.b.f.s.DefaultListableBeanFactory     : Autowiring by type from bean name 'org.springframework.boot.autoconfigure.jdbc.DataSourceInitializerInvoker' via constructor to bean named 'spring.datasource-org.springframework.boot.autoconfigure.jdbc.DataSourceProperties'
  50. 2020-05-26 11:26:14.065 DEBUG 14664 --- [           main] o.s.b.f.s.DefaultListableBeanFactory     : Autowiring by type from bean name 'org.springframework.boot.autoconfigure.jdbc.DataSourceInitializerInvoker' via constructor to bean named 'org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext@456d6c1e'
  51. 2020-05-26 11:26:14.227 DEBUG 14664 --- [           main] o.s.b.f.s.DefaultListableBeanFactory     : Creating shared instance of singleton bean 'hibernaProperties'
  52. 2020-05-26 11:26:14.230 DEBUG 14664 --- [           main] o.s.b.f.s.DefaultListableBeanFactory     : Creating shared instance of singleton bean 'jpaVendorAdapter'
  53. 2020-05-26 11:26:14.245 DEBUG 14664 --- [           main] j.LocalContainerEntityManagerFactoryBean : Building JPA container EntityManagerFactory for persistence unit 'default'
  54. 2020-05-26 11:26:14.294  INFO 14664 --- [           main] o.hibernate.jpa.internal.util.LogHelper  : HHH000204: Processing PersistenceUnitInfo [name: default]
  55. 2020-05-26 11:26:14.412  INFO 14664 --- [           main] org.hibernate.Version                    : HHH000412: Hibernate ORM core version 5.4.15.Final
  56. 2020-05-26 11:26:14.685  INFO 14664 --- [           main] o.hibernate.annotations.common.Version   : HCANN000001: Hibernate Commons Annotations {5.1.0.Final}
  57. 2020-05-26 11:26:14.906 DEBUG 14664 --- [           main] o.s.j.datasource.SimpleDriverDataSource  : Creating new JDBC Driver Connection to [jdbc:h2:mem:testdb;DB_CLOSE_DELAY=-1;DB_CLOSE_ON_EXIT=false]
  58. 2020-05-26 11:26:14.940  INFO 14664 --- [           main] org.hibernate.dialect.Dialect            : HHH000400: Using dialect: org.hibernate.dialect.H2Dialect
  59. Hibernate:

型

**SQL查询 *

  1. drop table if exists singer CASCADE 
  2. 2020-05-26 11:26:16.139 DEBUG 14664 --- [           main] o.s.j.datasource.SimpleDriverDataSource  : Creating new JDBC Driver Connection to [jdbc:h2:mem:testdb;DB_CLOSE_DELAY=-1;DB_CLOSE_ON_EXIT=false]
  3. Hibernate: 
  5.     create table singer (
  6.        id bigint generated by default as identity,
  7.         birth_date date,
  8.         description varchar(255),
  9.         first_name varchar(255),
  10.         last_name varchar(255),
  11.         photo blob,
  12.         primary key (id)
  13.     )

型
我找到了一个表达方式

  1. javax.validation.NoProviderFoundException: Unable to create a Configuration, because no Bean Validation provider could be found. Add a provider like Hibernate Validator (RI) to your classpath.
  2.     at javax.validation.Validation$GenericBootstrapImpl.configure(Validation.java:291) ~[validation-api-2.0.1.Final.jar:na]
  3.     at org.springframework.validation.beanvalidation.LocalValidatorFactoryBean.afterPropertiesSet(LocalValidatorFactoryBean.java:257) ~[spring-context-5.2.6.RELEASE.jar:5.2.6.RELEASE]
  4.     at org.springframework.validation.beanvalidation.OptionalValidatorFactoryBean.afterPropertiesSet(OptionalValidatorFactoryBean.java:40) ~[spring-context-5.2.6.RELEASE.jar:5.2.6.RELEASE]
  5.     at org.springframework.boot.autoconfigure.validation.ValidatorAdapter.afterPropertiesSet(ValidatorAdapter.java:83) ~[spring-boot-autoconfigure-2.3.0.RELEASE.jar:2.3.0.RELEASE]
  6.     at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1855) ~[spring-beans-5.2.6.RELEASE.jar:5.2.6.RELEASE]
  7.     at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1792) ~[spring-beans-5.2.6.RELEASE.jar:5.2.6.RELEASE]
  8.     at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:595) ~[spring-beans-5.2.6.RELEASE.jar:5.2.6.RELEASE]
  9.     at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:517) ~[spring-beans-5.2.6.RELEASE.jar:5.2.6.RELEASE]
  10.     at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:323) ~[spring-beans-5.2.6.RELEASE.jar:5.2.6.RELEASE]
  11.     at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:226) ~[spring-beans-5.2.6.RELEASE.jar:5.2.6.RELEASE]
  12.     at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:321) ~[spring-beans-5.2.6.RELEASE.jar:5.2.6.RELEASE]
  13.     at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) ~[spring-beans-5.2.6.RELEASE.jar:5.2.6.RELEASE]
  14.     at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:276) ~[spring-beans-5.2.6.RELEASE.jar:5.2.6.RELEASE]
  15.     at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1306) ~[spring-beans-5.2.6.RELEASE.jar:5.2.6.RELEASE]
  16.     at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1226) ~[spring-beans-5.2.6.RELEASE.jar:5.2.6.RELEASE]
  17.     at org.springframework.beans.factory.support.ConstructorResolver.resolveAutowiredArgument(ConstructorResolver.java:885) ~[spring-beans-5.2.6.RELEASE.jar:5.2.6.RELEASE]
  18.     at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:789) ~[spring-beans-5.2.6.RELEASE.jar:5.2.6.RELEASE]
  19.     at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:539) ~[spring-beans-5.2.6.RELEASE.jar:5.2.6.RELEASE]
  20.     at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1338) ~[spring-beans-5.2.6.RELEASE.jar:5.2.6.RELEASE]
  21.     at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1177) ~[spring-beans-5.2.6.RELEASE.jar:5.2.6.RELEASE]
  22.     at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:557) ~[spring-beans-5.2.6.RELEASE.jar:5.2.6.RELEASE]
  23.     at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:517) ~[spring-beans-5.2.6.RELEASE.jar:5.2.6.RELEASE]
  24.     at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:323) ~[spring-beans-5.2.6.RELEASE.jar:5.2.6.RELEASE]
  25.     at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:226) ~[spring-beans-5.2.6.RELEASE.jar:5.2.6.RELEASE]
  26.     at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:321) ~[spring-beans-5.2.6.RELEASE.jar:5.2.6.RELEASE]
  27.     at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) ~[spring-beans-5.2.6.RELEASE.jar:5.2.6.RELEASE]
  28.     at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:895) ~[spring-beans-5.2.6.RELEASE.jar:5.2.6.RELEASE]
  29.     at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:878) ~[spring-context-5.2.6.RELEASE.jar:5.2.6.RELEASE]
  30.     at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:550) ~[spring-context-5.2.6.RELEASE.jar:5.2.6.RELEASE]
  31.     at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:143) ~[spring-boot-2.3.0.RELEASE.jar:2.3.0.RELEASE]
  32.     at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:758) ~[spring-boot-2.3.0.RELEASE.jar:2.3.0.RELEASE]
  33.     at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:750) ~[spring-boot-2.3.0.RELEASE.jar:2.3.0.RELEASE]
  34.     at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:397) ~[spring-boot-2.3.0.RELEASE.jar:2.3.0.RELEASE]
  35.     at org.springframework.boot.SpringApplication.run(SpringApplication.java:315) ~[spring-boot-2.3.0.RELEASE.jar:2.3.0.RELEASE]
  36.     at org.springframework.boot.SpringApplication.run(SpringApplication.java:1237) ~[spring-boot-2.3.0.RELEASE.jar:2.3.0.RELEASE]
  37.     at org.springframework.boot.SpringApplication.run(SpringApplication.java:1226) ~[spring-boot-2.3.0.RELEASE.jar:2.3.0.RELEASE]
  38.     at com.example.demo.DemoApplication.main(DemoApplication.java:13) ~[main/:na]

型

spring-boot

1条答案

按热度按时间
3pvhb19x

3pvhb19x1#

你几乎就在那里了。事实上，你的数据库 * 是 * 空的。为什么？因为你的DBConfig类. prop.put("hibernate.hbm2ddl.auto", "create-drop");中的这一行（链接到该属性的文档）。你可以安全地删除它或将该属性设置为一个对你有意义的值。
您还需要设置照片属性（以及它的getter和setter）转换为Byte（这种类型也称为Wrapper Class）而不是byte，因为字节是一个不能设置为null的原始值。然而，在您的DB脚本中，您允许photo为null，因此，如果您不更改此代码，当你试图把DB列Map到Java对象时，它会导致一个异常。一旦你完成了这两件事，歌手的列表就会显示在浏览器中。
现在，一些最后的提示，因为你对编程有点陌生：
我已经检查了你的repo，你正在做很多你不需要做的工作和配置，因为你使用的是Sping Boot 和Sping Boot Data Jpa，而不仅仅是Spring。我建议你先开始全面使用Sping Boot ，然后学习Spring以及如何根据你的需求定制它，如果您需要单独使用Spring来满足您的需求，请使用Use this link作为网关来了解有关Sping Boot 和Sping Boot Data Jpa的更多信息。

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