我有一个基于Spring Framework的项目,它仅基于Java配置进行初始化。这意味着无需使用 web.xml 文件。
您可以在下图中看到项目的结构:
" main" class被称为AppInitializer,它位于初始值设定项文件夹
下AppInitializer
public class AppInitializer implements WebApplicationInitializer {
private static final String CONFIG_LOCATION = "com.project.app.config";
private static final String MAPPING_URL = "/";
@Override
public void onStartup(ServletContext servletContext) throws ServletException {
// Create the 'root' Spring application context
WebApplicationContext context = getContext();
// Manage the lifecycle of the root application context
servletContext.addListener(new ContextLoaderListener(context));
// Register and map the dispatcher servlet
ServletRegistration.Dynamic dispatcher = servletContext.addServlet("DispatcherServlet",
new DispatcherServlet(context));
dispatcher.setLoadOnStartup(1);
dispatcher.addMapping(MAPPING_URL);
}
private AnnotationConfigWebApplicationContext getContext() {
AnnotationConfigWebApplicationContext context = new AnnotationConfigWebApplicationContext();
context.setConfigLocation(CONFIG_LOCATION);
return context;
}
}
..而我的配置类位于 config 文件夹
中WebMvcConfig
@EnableWebMvc
@Configuration
@ComponentScan(basePackages = { "com.project.app" })
public class WebMvcConfig extends WebMvcConfigurerAdapter {
@Autowired
private Environment env;
@Override
public void addResourceHandlers(ResourceHandlerRegistry registry) {
registry.addResourceHandler("/resources/**").addResourceLocations("/resources/");
}
@Override
public void addViewControllers(ViewControllerRegistry registry) {
registry.addViewController("/").setViewName("hello");
}
@Bean
public ApplicationContextProvider applicationContextProvider() {
return new ApplicationContextProvider();
}
}
此时我想在我的项目中添加一个 postgres 数据库,因此我在CONFIG_LOCATION中创建了一个名为 db 的文件夹,这样春天就会#34 ;拿起" @Configuration类。(使用PGAdmin创建新数据库之后)..我创建了以下配置类。
数据源
@Component
@PropertySource("classpath:application.properties")
public class DataSources {
@Autowired
private Environment env;
@Bean
@Primary
public DataSource dataSource() {
org.apache.tomcat.jdbc.pool.DataSource ds = new org.apache.tomcat.jdbc.pool.DataSource();
String url = env.getProperty(SystemSettings.DS_URL);
String user = env.getProperty(SystemSettings.DS_USERNAME);
String pass = env.getProperty(SystemSettings.DS_PASSWORD);
ds.setDriverClassName("org.postgresql.Driver");
ds.setUrl(url);
ds.setUsername(user);
ds.setPassword(pass);
return ds;
}
}
而 SystemSettings 包含数据库的用户名,密码和网址
@Service
@Configuration
public class SystemSettings implements Settings {
public static final String DS_URL = "datasource.app.url";
public static final String DS_USERNAME = "datasource.app.username";
public static final String DS_PASSWORD = "datasource.app.password";
@Autowired
private Environment env;
@Override
public String get(String key) {
return env.getProperty(key);
}
}
这些值从 application.properties 文件中获取,如 DataSources 类中所示。
spring.jpa.database = POSTGRESQL
spring.jpa.show-SQL =真
spring.jpa.hibernate.ddl-AUTO =更新
datasource.app.type = POSTGRESQL
datasource.app.url = JDBC:在PostgreSQL://本地主机:5432 /应用
datasource.app.username = user datasource.app.password = pass
我继续添加一个实体类,它将代表项目中的一个简单表。 它位于 services / entities 文件夹
内StopJPA
@Entity
@Table(name = "stop")
public class StopJPA {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(name = "id")
private Long id;
@Column(name = "description")
private String stopDescription;
@Column(name = "idStop")
private String idStop;
public StopJPA() {
}
public StopJPA(String stopDescription, String idStop) {
this.stopDescription = stopDescription;
this.idStop = idStop;
}
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public String getStopDescription() {
return stopDescription;
}
public void setStopDescription(String stopDescription) {
this.stopDescription = stopDescription;
}
public String getIdStop() {
return idStop;
}
public void setIdStop(String idStop) {
this.idStop = idStop;
}
}
然后我为这个表创建了一个扩展 CrudRepository 的存储库接口。
StopRepository
/**
* Repository interface for StopJPA entities.
*/
@Repository
@RepositoryRestResource(collectionResourceRel = "stop", path = "stop")
public interface StopRepository extends CrudRepository<StopJPA, Long> {
StopJPA findById(@Param("id") Long id);
}
在完成所有这些设置和配置之后,我设法让项目运行但是没有在数据库中创建表。
我的 MAIN INTENTION 是配置Spring(通过使用 Spring Data JPA )和Hibernate,以使它们在不使用的情况下协同工作xml配置文件,没有Spring BOOT依赖项。后者意味着必须手动配置环境&#34;。
我在 DataSources 类中添加了一些配置,并在
中重命名了PersistenceContext
@Component
@EnableTransactionManagement
@PropertySource("classpath:application.properties")
public class PersistenceContext {
@Autowired
private Environment env;
@Bean
@Primary
public DataSource dataSource() throws ClassNotFoundException {
org.apache.tomcat.jdbc.pool.DataSource ds = new org.apache.tomcat.jdbc.pool.DataSource();
String url = env.getProperty(SystemSettings.DS_URL);
String user = env.getProperty(SystemSettings.USERNAME);
String pass = env.getProperty(SystemSettings.DS_PASSWORD);
ds.setDriverClassName("org.postgresql.Driver");
ds.setUrl(url);
ds.setUsername(user);
ds.setPassword(pass);
return ds;
}
@Bean
LocalContainerEntityManagerFactoryBean entityManagerFactory(DataSource dataSource) {
LocalContainerEntityManagerFactoryBean entityManagerFactoryBean = new LocalContainerEntityManagerFactoryBean();
entityManagerFactoryBean.setDataSource(dataSource);
entityManagerFactoryBean.setJpaVendorAdapter(new HibernateJpaVendorAdapter());
entityManagerFactoryBean.setPackagesToScan("com.project.app.services.entities");
Properties jpaProperties = new Properties();
// Configures the used database dialect. This allows Hibernate to create SQL
// that is optimized for the used database.
jpaProperties.put("hibernate.dialect", env.getRequiredProperty("hibernate.dialect"));
// Specifies the action that is invoked to the database when the Hibernate
// SessionFactory is created or closed.
jpaProperties.put("hibernate.hbm2ddl.auto",
env.getRequiredProperty("hibernate.hbm2ddl.auto"));
// If the value of this property is true, Hibernate writes all SQL
// statements to the console.
jpaProperties.put("hibernate.show_sql", env.getRequiredProperty("hibernate.show_sql"));
// If the value of this property is true, Hibernate will format the SQL
// that is written to the console.
jpaProperties.put("hibernate.format_sql", env.getRequiredProperty("hibernate.format_sql"));
entityManagerFactoryBean.setJpaProperties(jpaProperties);
return entityManagerFactoryBean;
}
/**
* Because we are using JPA, we have to create a transaction manager bean that integrates the
* JPA provider with the Spring transaction mechanism. We can do this by using the
* JpaTransactionManager class as the transaction manager of our application.
*
* We can configure the transaction manager bean by following these steps:
*
* -> Create a new JpaTransactionManager object. -> Configure the entity manager factory whose
* transactions are managed by the created JpaTransactionManager object.
**/
@Bean
JpaTransactionManager transactionManager(EntityManagerFactory entityManagerFactory) {
JpaTransactionManager transactionManager = new JpaTransactionManager();
transactionManager.setEntityManagerFactory(entityManagerFactory);
return transactionManager;
}
}
Ans还更新了属性文件
hibernate.dialect = org.hibernate.dialect.PostgreSQLDialect
hibernate.hbm2ddl.auto = create-drop hibernate.show_sql = false
hibernate.format_sql = truedatasource.app.type = POSTGRESQL
datasource.app.driverClassName = org.postgresql.Driver
datasource.app.url = JDBC:在PostgreSQL://本地主机:5432 /应用
datasource.app.username = user datasource.app.password = pass
不幸的是现在我收到了这个错误
严重:无法创建池的初始连接。 java.sql.SQLException:org.postgresql.Driver at ...... 引起: java.lang.ClassNotFoundException: org.postgresql.Driver at ......
我不知道为什么它给了我这个例外。 maven依赖是存在的,驱动程序也在类路径中。 。有帮助吗?
答案 0 :(得分:1)
JPA未指定DDL生成/迁移。默认情况下,Hibernate不执行DDL生成/迁移,但如果configure your persistence.xml properly,则可以执行此操作。
答案 1 :(得分:0)
嗯,这完全是关于Classpath ..我已经在我的 pom.xml 中有了依赖,但我需要做的是
<强>聚甲醛强>
<!-- Postgres -->
<dependency>
<groupId>org.postgresql</groupId>
<artifactId>postgresql</artifactId>
<version>9.4-1205-jdbc42</version>
<scope>provided</scope>
</dependency>