[英]Hibernate auto_increment MySQL
我正在使用 Eclipse、Xammp(tomcat 和 MySQL DB)和 Hibernate。
這一切都很好,但我無法創建實體的 ID 將是數據庫中的auto_increment
我的實體:
package com.jwt.hibernate.bean;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import org.hibernate.annotations.GenericGenerator;
@Entity
public class User {
@Id
@GenericGenerator(name="generator", strategy="increment")
@GeneratedValue(generator="generator")
private Long userId;
private String userName;
private String password1;
private String email;
private String phone;
private String city;
public Long getUserId() {
return userId;
}
public void setUserId(Long userId) {
this.userId = userId;
}
public String getUserName() {
return userName;
}
public void setUserName(String userName) {
this.userName = userName;
}
public String getPassword1() {
return password1;
}
public void setPassword1(String password1) {
this.password1 = password1;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
public String getPhone() {
return phone;
}
public void setPhone(String phone) {
this.phone = phone;
}
public String getCity() {
return city;
}
public void setCity(String city) {
this.city = city;
}
}
我使用Hibernate XML Mapping file(hbm.xml)
的插件為此實體創建了一個 hbm.xml,並使用了Hibernate XML Mapping file(hbm.xml)
:創建了 hbm.xml:
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<!-- Generated 06.05.2016 11:59:26 by Hibernate Tools 3.5.0.Final -->
<hibernate-mapping>
<class name="com.jwt.hibernate.bean.User" table="USER">
<id name="userId" type="java.lang.Long">
<column name="USERID" />
<generator class="assigned" />
</id>
<property name="userName" type="java.lang.String">
<column name="USERNAME" />
</property>
<property name="password1" type="java.lang.String">
<column name="PASSWORD1" />
</property>
<property name="email" type="java.lang.String">
<column name="EMAIL" />
</property>
<property name="phone" type="java.lang.String">
<column name="PHONE" />
</property>
<property name="city" type="java.lang.String">
<column name="CITY" />
</property>
</class>
</hibernate-mapping>
我的 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.jdbc.Driver</property>
<property name="hibernate.connection.url">jdbc:mysql://localhost:3306/test</property>
<property name="hibernate.connection.username">root</property>
<property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
<property name="current_session_context_class">thread</property>
<property name="hbm2ddl.auto">create-drop</property>
<property name="show_sql">true</property>
<mapping resource="/com/jwt/hibernate/bean/User.hbm.xml" />
</session-factory>
</hibernate-configuration>
如果我啟動我的代碼,控制台會執行以下操作:
Hibernate: drop table if exists USER
Hibernate: create table USER (USERID bigint not null, USERNAME varchar(255), PASSWORD1 varchar(255), EMAIL varchar(255), PHONE varchar(255), CITY varchar(255), primary key (USERID))
一切都很好,但我的 ID 不是auto_increment
,我不知道為什么。 我嘗試了很多注釋。 示例ManyToMany
或ManyToOne
其他注釋有效,但@GeneratedValue
用
<id name="userId" type="java.lang.Long">
<column name="USERID" />
<generator class="native" />
</id>
而不是以下行
<id name="userId" type="java.lang.Long">
<column name="USERID" />
<generator class="assigned" />
</id>
您可以在 getUserId 方法上使用此注釋:
@Id
@GenericGenerator(name = "id_generator", strategy = "increment")
@GeneratedValue(generator = "id_generator")
@Column(name = "id", unique = true, nullable = false)
public Long getUserId() {
return userId;
}
或者您也可以在當前代碼中執行此操作,只需在 getUserId 方法上指定 @Column
@Column(name = "id", unique = true, nullable = false)
public Long getUserId() {
return userId;
}
如果您將使用注釋,這就足夠了
@Id
@GeneratedValue
@Column(name = "id")
public Long getUserId() {
return userId;
}
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