在 Spring、Hibernate 和 PostgreSQL 中插入时在列中生成时间戳
Generate a timestamp in a column while inserting in Spring, Hibernate and PostgreSQL
我正在学习 Spring、Hibernate 和 PostgreSQL。我有一个具有时间戳字段的实体。此时间戳的数据库列称为 datecreated
.
这个时间戳应该是自动生成的,但不是。插入记录时,只生成空值,而不是日期。
我尝试了互联网上的许多解决方案组合,但我没有成功。我试过这个:
@CreationTimestamp
private Date dateCreated;
@CreationTimestamp
@Column
private Date dateCreated;
@CreationTimestamp
@Column
private Date dateCreated = new Date();
@CreationTimestamp
@Temporal(TemporalType.TIMESTAMP)
@Column
private Date dateCreated = new Date();
@Temporal(TemporalType.TIMESTAMP)
@Column
private Date dateCreated = new Date();
@Temporal(TemporalType.TIMESTAMP)
@Column(updatable = false)
private Date dateCreated = new Date();
@CreationTimestamp
@Temporal(TemporalType.TIMESTAMP)
@Column(updatable = false)
private Date dateCreated = new Date();
@CreationTimestamp
@Temporal(TemporalType.TIMESTAMP)
@Column(updatable = false)
private Date dateCreated;
@CreationTimestamp
@Temporal(TemporalType.TIMESTAMP)
@Column(updatable = false)
private Date dateCreated;
@PrePersist
protected void onCreate() {
dateCreated = new Date();
}
这就是我得到的:
如何让它生成时间戳?
这里是项目文件 Image.java 模型,pom.xml,import.sql ddl,hibernate.cfg.xml 文件:
Image.java
package com.howtodoinjava.demo.spring.domain;
import javax.persistence.*;
import java.util.Date;
import org.hibernate.annotations.CreationTimestamp;
@Entity
@Table(name = "images")
public class Image {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
@Column(nullable = false, length = 300)
private String title;
@Column(nullable = false)
private String url;
@Column(nullable = false)
private String author;
@CreationTimestamp
@Column
private Date dateCreated = new Date();
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public String getUrl() {
return url;
}
public void setUrl(String url) {
this.url = url;
}
public String getAuthor() {
return author;
}
public void setAuthor(String author) {
this.author = author;
}
public Date getDate() {
return dateCreated;
}
public void setDate(Date dateCreated) {
this.dateCreated = dateCreated;
}
public Image() {}
public Image(Long id, String title, String url, String author) {
this.id = id;
this.title = title;
this.url = url;
this.author = author;
}
@Override
public String toString() {
return "Post{" +
"id=" + id +
", title='" + title + '\'' +
", url='" + url + '\'' +
", author=" + author +
", date=" + dateCreated +
'}';
}
}
pom.xml
<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>
<groupId>com.bitMiners</groupId>
<artifactId>pdf-app</artifactId>
<version>0.0.1</version>
<packaging>war</packaging>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<aspect.version>1.9.2</aspect.version>
<jackson.version>2.9.8</jackson.version>
<hibernate.version>5.4.2.Final</hibernate.version>
<hibernate.validator.version>6.0.13.Final</hibernate.validator.version>
<c3p0.version>0.9.5.2</c3p0.version>
</properties>
<dependencies>
<!-- servlets and jps -->
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>jstl</artifactId>
<version>1.2</version>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>4.0.1</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>org.apache.tiles</groupId>
<artifactId>tiles-extras</artifactId>
<version>3.0.8</version>
<exclusions>
<exclusion>
<groupId>org.slf4j</groupId>
<artifactId>jcl-over-slf4j</artifactId>
</exclusion>
<exclusion>
<groupId>jboss</groupId>
<artifactId>javassist</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>commons-fileupload</groupId>
<artifactId>commons-fileupload</artifactId>
<version>1.3.3</version>
</dependency>
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-io</artifactId>
<version>1.3.2</version>
</dependency>
<!--hibernate-->
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-core</artifactId>
<version>${hibernate.version}</version>
<exclusions>
<exclusion>
<groupId>org.javassist</groupId>
<artifactId>javassist</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-entitymanager</artifactId>
<version>${hibernate.version}</version>
</dependency>
<!-- Hibernate-C3P0 Integration -->
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-c3p0</artifactId>
<version>${hibernate.version}</version>
</dependency>
<!-- c3p0 -->
<dependency>
<groupId>com.mchange</groupId>
<artifactId>c3p0</artifactId>
<version>${c3p0.version}</version>
</dependency>
<!-- validation -->
<dependency>
<groupId>org.hibernate.validator</groupId>
<artifactId>hibernate-validator</artifactId>
<version>${hibernate.validator.version}</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.34</version>
</dependency>
<!-- for rest services -->
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>${jackson.version}</version>
</dependency>
<dependency>
<groupId>javax.servlet.jsp</groupId>
<artifactId>javax.servlet.jsp-api</artifactId>
<version>2.3.3</version>
</dependency>
<!-- For Aop -->
<dependency>
<groupId>org.aspectj</groupId>
<artifactId>aspectjrt</artifactId>
<version>${aspect.version}</version>
</dependency>
<dependency>
<groupId>org.aspectj</groupId>
<artifactId>aspectjweaver</artifactId>
<version>${aspect.version}</version>
</dependency>
<!-- To Send Email -->
<dependency>
<groupId>com.sun.mail</groupId>
<artifactId>javax.mail</artifactId>
<version>1.5.4</version>
</dependency>
<dependency>
<groupId>org.springframework.security</groupId>
<artifactId>spring-security-core</artifactId>
<version>5.2.0.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>5.2.0.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-tx</artifactId>
<version>5.2.0.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-orm</artifactId>
<version>5.2.0.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework.security</groupId>
<artifactId>spring-security-web</artifactId>
<version>5.2.0.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework.security</groupId>
<artifactId>spring-security-config</artifactId>
<version>5.2.0.RELEASE</version>
</dependency>
<!--logging-->
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-core</artifactId>
<version>2.8.2</version>
</dependency>
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-api</artifactId>
<version>2.8.2</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.apache.logging.log4j/log4j-web -->
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-web</artifactId>
<version>2.13.3</version>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-simple</artifactId>
<version>1.7.30</version>
</dependency>
<!-- PostgreSQL -->
<dependency>
<groupId>org.postgresql</groupId>
<artifactId>postgresql</artifactId>
<version>42.2.16</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context-support</artifactId>
<version>5.1.3.RELEASE</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.springframework.security/spring-security-taglibs -->
<dependency>
<groupId>org.springframework.security</groupId>
<artifactId>spring-security-taglibs</artifactId>
<version>5.1.2.RELEASE</version>
</dependency>
</dependencies>
<build>
<!-- To define the plugin version in your parent POM -->
<pluginManagement>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-surefire-plugin</artifactId>
<version>2.22.1</version>
</plugin>
</plugins>
</pluginManagement>
<plugins>
<!-- To use the plugin goals in your POM or parent POM -->
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-surefire-plugin</artifactId>
<version>2.22.1</version>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<configuration>
<source>1.8</source>
<target>1.8</target>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-war-plugin</artifactId>
<version>3.2.2</version>
</plugin>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
import.sql
这个文件放在一个路径下:src/main/resources/import.sql并且在运行项目时自动执行。这取自教程 https://dzone.com/articles/spring-security-5-form-login-with-database-provide
-- ...
INSERT INTO images (title, url, author) VALUES ('lanszaft', 'https://i.imgur.com/sZ64fVI.jpg', 'Oskar Kamiński');
INSERT INTO images (title, url, author) VALUES ('kobieta w kapeluszu', 'https://i.imgur.com/spMsvHe.png', 'Pablo Picasso');
hibernate.cfg.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<property name="hibernate.archive.autodetection">class,hbm</property>
<property name="hibernate.show_sql">true</property>
<property name="hibernate.connection.url">jdbc:postgresql://localhost:5432/postgres</property> <!-- BD Mane -->
<property name="hibernate.connection.driver_class">org.postgresql.Driver</property>
<property name="hibernate.connection.username">user32</property>
<property name="hibernate.connection.password">pa$$word</property>
<property name="hibernate.dialect">org.hibernate.dialect.PostgreSQL95Dialect</property>
<property name="hibernate.connection.pool.size">1</property>
<property name="hibernate.hbm2ddl.auto">create</property>
<property name="hibernate.enable_lazy_load_no_trans">true</property>
<property name="hibernate.jdbc.lob.non_contextual_creation">true</property>
<property name="hibernate.c3p0.min_size">5</property>
<property name="hibernate.c3p0.max_size">20</property>
<property name="hibernate.c3p0.acquire_increment">2</property>
<property name="hibernate.c3p0.timeout">1800</property>
<property name="hibernate.c3p0.max_statements">150</property>
<mapping class="com.howtodoinjava.demo.spring.domain.User"/>
<mapping class="com.howtodoinjava.demo.spring.domain.Authority"/>
<mapping class="com.howtodoinjava.demo.spring.domain.AuthorityType"/>
<mapping class="com.howtodoinjava.demo.spring.domain.Image"/>
</session-factory>
</hibernate-configuration>
如果您使用 JPA 或本机休眠方法从应用程序内部进行插入,则 prePersist 和其他 @createTimeStamp 挂钩会起作用。如果您只是 运行 从应用程序上下文外部插入,hibernate 将无法知道什么是 DML 运行ning,因此永远不会调用挂钩。如果您希望即使在 运行 插入时从外部,创建的时间戳也应该自动填充,您需要添加 table 级别的 DDL 指令。
例如:ALTER TABLE mytable ALTER COLUMN datecreated SET DEFAULT now();
现在关于休眠的自动 DDL 能力,xml 属性 <property name="hibernate.hbm2ddl.auto">create</property>
从实体定义而不是 DML 生成 DDL。因此,您还可以将 DEFAULT 时间戳值嵌入相关实体的列定义中,如此或类似:
@Column(name="datecreated", columnDefinition="TIMESTAMP DEFAULT CURRENT_TIMESTAMP")
这将确保在创建 table 时,使用休眠设置的自动 DDL 属性 应用定义。
希望这能说明问题
在您的图像模型中 class,使用时间戳
@CreationTimestamp
@Column
private Timestamp timestamp;
我正在学习 Spring、Hibernate 和 PostgreSQL。我有一个具有时间戳字段的实体。此时间戳的数据库列称为 datecreated
.
这个时间戳应该是自动生成的,但不是。插入记录时,只生成空值,而不是日期。
我尝试了互联网上的许多解决方案组合,但我没有成功。我试过这个:
@CreationTimestamp
private Date dateCreated;
@CreationTimestamp
@Column
private Date dateCreated;
@CreationTimestamp
@Column
private Date dateCreated = new Date();
@CreationTimestamp
@Temporal(TemporalType.TIMESTAMP)
@Column
private Date dateCreated = new Date();
@Temporal(TemporalType.TIMESTAMP)
@Column
private Date dateCreated = new Date();
@Temporal(TemporalType.TIMESTAMP)
@Column(updatable = false)
private Date dateCreated = new Date();
@CreationTimestamp
@Temporal(TemporalType.TIMESTAMP)
@Column(updatable = false)
private Date dateCreated = new Date();
@CreationTimestamp
@Temporal(TemporalType.TIMESTAMP)
@Column(updatable = false)
private Date dateCreated;
@CreationTimestamp
@Temporal(TemporalType.TIMESTAMP)
@Column(updatable = false)
private Date dateCreated;
@PrePersist
protected void onCreate() {
dateCreated = new Date();
}
这就是我得到的:
如何让它生成时间戳? 这里是项目文件 Image.java 模型,pom.xml,import.sql ddl,hibernate.cfg.xml 文件:
Image.java
package com.howtodoinjava.demo.spring.domain;
import javax.persistence.*;
import java.util.Date;
import org.hibernate.annotations.CreationTimestamp;
@Entity
@Table(name = "images")
public class Image {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
@Column(nullable = false, length = 300)
private String title;
@Column(nullable = false)
private String url;
@Column(nullable = false)
private String author;
@CreationTimestamp
@Column
private Date dateCreated = new Date();
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public String getUrl() {
return url;
}
public void setUrl(String url) {
this.url = url;
}
public String getAuthor() {
return author;
}
public void setAuthor(String author) {
this.author = author;
}
public Date getDate() {
return dateCreated;
}
public void setDate(Date dateCreated) {
this.dateCreated = dateCreated;
}
public Image() {}
public Image(Long id, String title, String url, String author) {
this.id = id;
this.title = title;
this.url = url;
this.author = author;
}
@Override
public String toString() {
return "Post{" +
"id=" + id +
", title='" + title + '\'' +
", url='" + url + '\'' +
", author=" + author +
", date=" + dateCreated +
'}';
}
}
pom.xml
<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>
<groupId>com.bitMiners</groupId>
<artifactId>pdf-app</artifactId>
<version>0.0.1</version>
<packaging>war</packaging>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<aspect.version>1.9.2</aspect.version>
<jackson.version>2.9.8</jackson.version>
<hibernate.version>5.4.2.Final</hibernate.version>
<hibernate.validator.version>6.0.13.Final</hibernate.validator.version>
<c3p0.version>0.9.5.2</c3p0.version>
</properties>
<dependencies>
<!-- servlets and jps -->
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>jstl</artifactId>
<version>1.2</version>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>4.0.1</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>org.apache.tiles</groupId>
<artifactId>tiles-extras</artifactId>
<version>3.0.8</version>
<exclusions>
<exclusion>
<groupId>org.slf4j</groupId>
<artifactId>jcl-over-slf4j</artifactId>
</exclusion>
<exclusion>
<groupId>jboss</groupId>
<artifactId>javassist</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>commons-fileupload</groupId>
<artifactId>commons-fileupload</artifactId>
<version>1.3.3</version>
</dependency>
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-io</artifactId>
<version>1.3.2</version>
</dependency>
<!--hibernate-->
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-core</artifactId>
<version>${hibernate.version}</version>
<exclusions>
<exclusion>
<groupId>org.javassist</groupId>
<artifactId>javassist</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-entitymanager</artifactId>
<version>${hibernate.version}</version>
</dependency>
<!-- Hibernate-C3P0 Integration -->
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-c3p0</artifactId>
<version>${hibernate.version}</version>
</dependency>
<!-- c3p0 -->
<dependency>
<groupId>com.mchange</groupId>
<artifactId>c3p0</artifactId>
<version>${c3p0.version}</version>
</dependency>
<!-- validation -->
<dependency>
<groupId>org.hibernate.validator</groupId>
<artifactId>hibernate-validator</artifactId>
<version>${hibernate.validator.version}</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.34</version>
</dependency>
<!-- for rest services -->
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>${jackson.version}</version>
</dependency>
<dependency>
<groupId>javax.servlet.jsp</groupId>
<artifactId>javax.servlet.jsp-api</artifactId>
<version>2.3.3</version>
</dependency>
<!-- For Aop -->
<dependency>
<groupId>org.aspectj</groupId>
<artifactId>aspectjrt</artifactId>
<version>${aspect.version}</version>
</dependency>
<dependency>
<groupId>org.aspectj</groupId>
<artifactId>aspectjweaver</artifactId>
<version>${aspect.version}</version>
</dependency>
<!-- To Send Email -->
<dependency>
<groupId>com.sun.mail</groupId>
<artifactId>javax.mail</artifactId>
<version>1.5.4</version>
</dependency>
<dependency>
<groupId>org.springframework.security</groupId>
<artifactId>spring-security-core</artifactId>
<version>5.2.0.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>5.2.0.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-tx</artifactId>
<version>5.2.0.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-orm</artifactId>
<version>5.2.0.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework.security</groupId>
<artifactId>spring-security-web</artifactId>
<version>5.2.0.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework.security</groupId>
<artifactId>spring-security-config</artifactId>
<version>5.2.0.RELEASE</version>
</dependency>
<!--logging-->
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-core</artifactId>
<version>2.8.2</version>
</dependency>
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-api</artifactId>
<version>2.8.2</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.apache.logging.log4j/log4j-web -->
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-web</artifactId>
<version>2.13.3</version>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-simple</artifactId>
<version>1.7.30</version>
</dependency>
<!-- PostgreSQL -->
<dependency>
<groupId>org.postgresql</groupId>
<artifactId>postgresql</artifactId>
<version>42.2.16</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context-support</artifactId>
<version>5.1.3.RELEASE</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.springframework.security/spring-security-taglibs -->
<dependency>
<groupId>org.springframework.security</groupId>
<artifactId>spring-security-taglibs</artifactId>
<version>5.1.2.RELEASE</version>
</dependency>
</dependencies>
<build>
<!-- To define the plugin version in your parent POM -->
<pluginManagement>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-surefire-plugin</artifactId>
<version>2.22.1</version>
</plugin>
</plugins>
</pluginManagement>
<plugins>
<!-- To use the plugin goals in your POM or parent POM -->
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-surefire-plugin</artifactId>
<version>2.22.1</version>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<configuration>
<source>1.8</source>
<target>1.8</target>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-war-plugin</artifactId>
<version>3.2.2</version>
</plugin>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
import.sql
这个文件放在一个路径下:src/main/resources/import.sql并且在运行项目时自动执行。这取自教程 https://dzone.com/articles/spring-security-5-form-login-with-database-provide
-- ...
INSERT INTO images (title, url, author) VALUES ('lanszaft', 'https://i.imgur.com/sZ64fVI.jpg', 'Oskar Kamiński');
INSERT INTO images (title, url, author) VALUES ('kobieta w kapeluszu', 'https://i.imgur.com/spMsvHe.png', 'Pablo Picasso');
hibernate.cfg.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<property name="hibernate.archive.autodetection">class,hbm</property>
<property name="hibernate.show_sql">true</property>
<property name="hibernate.connection.url">jdbc:postgresql://localhost:5432/postgres</property> <!-- BD Mane -->
<property name="hibernate.connection.driver_class">org.postgresql.Driver</property>
<property name="hibernate.connection.username">user32</property>
<property name="hibernate.connection.password">pa$$word</property>
<property name="hibernate.dialect">org.hibernate.dialect.PostgreSQL95Dialect</property>
<property name="hibernate.connection.pool.size">1</property>
<property name="hibernate.hbm2ddl.auto">create</property>
<property name="hibernate.enable_lazy_load_no_trans">true</property>
<property name="hibernate.jdbc.lob.non_contextual_creation">true</property>
<property name="hibernate.c3p0.min_size">5</property>
<property name="hibernate.c3p0.max_size">20</property>
<property name="hibernate.c3p0.acquire_increment">2</property>
<property name="hibernate.c3p0.timeout">1800</property>
<property name="hibernate.c3p0.max_statements">150</property>
<mapping class="com.howtodoinjava.demo.spring.domain.User"/>
<mapping class="com.howtodoinjava.demo.spring.domain.Authority"/>
<mapping class="com.howtodoinjava.demo.spring.domain.AuthorityType"/>
<mapping class="com.howtodoinjava.demo.spring.domain.Image"/>
</session-factory>
</hibernate-configuration>
如果您使用 JPA 或本机休眠方法从应用程序内部进行插入,则 prePersist 和其他 @createTimeStamp 挂钩会起作用。如果您只是 运行 从应用程序上下文外部插入,hibernate 将无法知道什么是 DML 运行ning,因此永远不会调用挂钩。如果您希望即使在 运行 插入时从外部,创建的时间戳也应该自动填充,您需要添加 table 级别的 DDL 指令。
例如:ALTER TABLE mytable ALTER COLUMN datecreated SET DEFAULT now();
现在关于休眠的自动 DDL 能力,xml 属性 <property name="hibernate.hbm2ddl.auto">create</property>
从实体定义而不是 DML 生成 DDL。因此,您还可以将 DEFAULT 时间戳值嵌入相关实体的列定义中,如此或类似:
@Column(name="datecreated", columnDefinition="TIMESTAMP DEFAULT CURRENT_TIMESTAMP")
这将确保在创建 table 时,使用休眠设置的自动 DDL 属性 应用定义。
希望这能说明问题
在您的图像模型中 class,使用时间戳
@CreationTimestamp
@Column
private Timestamp timestamp;