【发布时间】：2021-10-21 09:57:10
【问题描述】：
这是我在Java Hibernate 的第二天。我正在学习这个 YouTube 教程：
Hibernate Tutorial | Configuration File
我正在仔细跟踪每一步。我的问题是我可以多次推送相同的记录：
mysql> select * from Alien;
+------+-------+--------+
| aid | aname | acolor |
+------+-------+--------+
| 101 | Navin | Green |
| 101 | Navin | Green |
| 101 | Navin | Green |
| 101 | Navin | Green |
| 101 | Navin | Green |
| 101 | Navin | Green |
| 101 | Navin | Green |
+------+-------+--------+
7 rows in set (0.00 sec)
这是我的文件。
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.connection.driver_class">com.mysql.cj.jdbc.Driver</property>
<property name="hibernate.connection.password">cosmonauts</property>
<property name="hibernate.connection.url">jdbc:mysql://localhost:3306/testdb</property>
<property name="hibernate.connection.username">root</property>
<property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
<property name="hibernate.hbm2ddl.auto">
update
</property>
<property name="show_sql=true"></property>
</session-factory>
</hibernate-configuration>
Alien.java
import javax.persistence.Entity;
import javax.persistence.Id;
@Entity
public class Alien { // POJO
@Id
private int aid;
private String aname;
private String acolor;
... //getters and setters
}
App.java // 主类
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.boot.registry.StandardServiceRegistry;
import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
import org.hibernate.cfg.Configuration;
public class App {
public static void main(String[] args) {
Alien telusko = new Alien();
telusko.setAid(101);
telusko.setAname("Navin");
telusko.setAcolor("Green");
Configuration configuration = new Configuration().configure().addAnnotatedClass(Alien.class);
StandardServiceRegistry reg = new StandardServiceRegistryBuilder().applySettings(configuration.getProperties()).build();
SessionFactory sf = configuration.buildSessionFactory(reg);
Session session = sf.openSession();
Transaction tx = session.beginTransaction();
session.save(telusko);
tx.commit();
}
}
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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.student.sample</groupId>
<artifactId>StudentSystem</artifactId>
<version>0.0.1-SNAPSHOT</version>
<dependencies>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.26</version>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-core</artifactId>
<version>5.5.6.Final</version>
</dependency>
</dependencies>
</project>
我是不是误会了什么。请纠正我的错误。
在控制台上我得到了这个：
Aug 19, 2021 10:43:44 PM org.hibernate.Version logVersion
INFO: HHH000412: Hibernate ORM core version 5.5.6.Final
Aug 19, 2021 10:43:45 PM org.hibernate.annotations.common.reflection.java.JavaReflectionManager <clinit>
INFO: HCANN000001: Hibernate Commons Annotations {5.1.2.Final}
Aug 19, 2021 10:43:45 PM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl configure
WARN: HHH10001002: Using Hibernate built-in connection pool (not for production use!)
Aug 19, 2021 10:43:45 PM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl buildCreator
INFO: HHH10001005: using driver [com.mysql.cj.jdbc.Driver] at URL [jdbc:mysql://localhost:3306/testdb]
Aug 19, 2021 10:43:45 PM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl buildCreator
INFO: HHH10001001: Connection properties: {password=****, user=root}
Aug 19, 2021 10:43:45 PM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl buildCreator
INFO: HHH10001003: Autocommit mode: false
Aug 19, 2021 10:43:45 PM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl$PooledConnections <init>
INFO: HHH000115: Hibernate connection pool size: 20 (min=1)
Aug 19, 2021 10:43:45 PM org.hibernate.dialect.Dialect <init>
INFO: HHH000400: Using dialect: org.hibernate.dialect.MySQLDialect
Aug 19, 2021 10:43:45 PM org.hibernate.resource.transaction.backend.jdbc.internal.DdlTransactionIsolatorNonJtaImpl getIsolatedConnection
INFO: HHH10001501: Connection obtained from JdbcConnectionAccess [org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator$ConnectionProviderJdbcConnectionAccess@27e7c77f] for (non-JTA) DDL execution was not in auto-commit mode; the Connection 'local transaction' will be committed and the Connection will be set into auto-commit mode.
Aug 19, 2021 10:43:45 PM org.hibernate.engine.transaction.jta.platform.internal.JtaPlatformInitiator initiateService
INFO: HHH000490: Using JtaPlatform implementation: [org.hibernate.engine.transaction.jta.platform.internal.NoJtaPlatform]
请加入。
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标签： java eclipse hibernate annotations