我尝试使用jpa与spring-orm和hibernate一起使用。我有一个名为TRADES的mysql数据库表，我想使用jpa来操作它。我尝试使用persistence.xml测试EntityManager的创建，但是我收到了一个异常：“没有名为[persistence-unit-name from persistence.xml]的EntityManager的持久性提供程序”。根据我在类似问题中观察到的情况，这意味着我的情况下找不到persistence.xml文件。当我尝试测试此配置时，我收到了一个异常，我认为是因为找不到persistence.xml。
SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".
SLF4J: Defaulting to no-operation (NOP) logger implementation
SLF4J: See http://www.slf4j.org/codes.html#StaticLoggerBinder for further details.
Exception in thread "main" javax.persistence.PersistenceException: No Persistence provider for EntityManager named trade-mysql-pu
at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:54)
at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:32)
at com.madhusudhan.jsd.jpa.EntityManagerTest.init(EntityManagerTest.java:16)
at com.madhusudhan.jsd.jpa.EntityManagerTest.main(EntityManagerTest.java:29)
我弄不清楚为什么会出现这种情况。您能帮助我吗？ 谢谢。
表格：
create table TRADES (ID int NOT NULL,
ACCOUNT VARCHAR(20) NOT NULL,
SECURITY VARCHAR(10) NOT NULL,
QUANTITY INT NOT NULL,
STATUS VARCHAR(10),
DIRECTION VARCHAR(10)
);
这个表的实体类：
package com.madhusudhan.jsd.domain.jpa;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;
@Entity
@Table(name="trades")
public class Trade {
private int id;
private String direction;
private String account;
private String security;
private String status;
private int quantity;
@Column(nullable=false)
@Id
@GeneratedValue(strategy=GenerationType.AUTO)
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
@Column
public String getDirection() {
return direction;
}
public void setDirection(String direction) {
this.direction = direction;
}
@Column
public String getAccount() {
return account;
}
public void setAccount(String account) {
this.account = account;
}
@Column
public String getSecurity() {
return security;
}
public void setSecurity(String security) {
this.security = security;
}
@Column
public String getStatus() {
return status;
}
public void setStatus(String status) {
this.status = status;
}
@Column
public int getQuantity() {
return quantity;
}
public void setQuantity(int quantity) {
this.quantity = quantity;
}
@Override
public String toString() {
return "Trade [id=" + id + ", direction=" + direction + ", account="
+ account + ", security=" + security + ", status=" + status
+ "]";
}
}
在src/main/resources/META-INF中的persistence.xml文件
<persistence xmlns="http://java.sun.com/xml/ns/persistence"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd"
version="2.0">
<persistence-unit name="trade-mysql-pu" transaction-type="RESOURCE_LOCAL">
<provider>org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter</provider>
<class>com.madhusudhan.jsd.domain.jpa.Trade</class>
<properties>
<property name="hibernate.hbm2ddl.auto" value="validate" />
<property name="show_sql" value="true" />
<property name="hibernate.connection.url" value="jdbc:mysql://localhost:3306/JSDATA"/>
<property name="hibernate.connection.driver_class" value="com.mysql.jdbc.Driver"/>
<property name="hibernate.connection.username" value="prospring4"/>
<property name="hibernate.connection.password" value="prospring4"/>
<property name="hibernate.connection.pool_size" value="1"/>
<property name="hibernate.dialect" value="org.hibernate.dialect.MySQL5Dialect"/>
</properties>
</persistence-unit>
</persistence>
这是测试类：
package com.madhusudhan.jsd.jpa;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;
import com.madhusudhan.jsd.domain.jpa.Trade;
public class EntityManagerTest {
private EntityManagerFactory factory;
private EntityManager entityManager;
private void init() {
factory = Persistence.createEntityManagerFactory("trade-mysql-pu");
entityManager = factory.createEntityManager();
}
public void persistTrade(Trade t) {
entityManager.persist(t);
}
public static void main(String[] args) {
EntityManagerTest test = new EntityManagerTest();
test.init();
}
}
build.gradle中的依赖项：
dependencies {
compile 'org.springframework:spring-context:4.1.6.RELEASE'
compile 'org.springframework:spring-jdbc:4.1.6.RELEASE'
compile 'org.springframework:spring-orm:4.1.6.RELEASE'
compile 'commons-dbcp:commons-dbcp:1.4'
compile 'mysql:mysql-connector-java:5.1.18'
compile 'org.hibernate:hibernate-core:3.6.0.Final'
compile 'org.hibernate:hibernate-entitymanager:3.6.0.Final'
compile 'junit:junit:4.7'
compile 'log4j:log4j:1.2.14'
}